Thursday, December 27, 2012

Electronic Chart Plotters

As part of planning out our boat, I need to decide on all the navigation electronics.  There are many different parts to the question, but the Chart Plotter is the best place to start.  It's the heart of the navigation system, and forces the answer to a number of follow-on questions.  Electronics vendors love to lock in their customers with systems of interoperable components.  Customers benefit from the integration and interoperability, but quickly find themselves locked into the vendor since changing one component to a different vendor causes a ripple effect of change that quickly becomes too expensive.  When products are really good, customers welcome the integration and do not object to the lock in since they would buy the good products anyway.  Apple is a good example.  But when products are marginal, customers quickly become resentful of the lock-in and a more adversarial relationship emerges between the vendor and customers.  Microsoft is a good example.  With Navigation systems, the primary lock-in is between chart plotters and radar.  Radar data is pretty uniformly transmitted over ethernet, but in a proprietary format so it can only be displayed by the same vendor's chart plotters.  Selecting a vendor for one means selecting the same vendor for both.

In my case, I'm going to let the chart plotter take the lead in the decision.  With one notable exception, I think all the big vendors' radar systems are comparable.  Radar has been around a long time and is no big secret, so everyone has good products.  The notable exception is Simrad who have developed a high-frequency (I think) radar that yields much higher resolution images.  It's a nice advance, but comes with some draw backs as well.  But I'm still going to let the chart plotter lead my decision since there are LOTS of differences between vendors.

Before diving in, I should also add some more background.  I spent my career building high tech products, almost all of which were a combination of hardware and software rolled together into a stand-alone product, much like all the components in our navigation gear.  As a result, I'm pretty demanding about tech products, and have very little tolerance for poor products.  I say this to warn you that I may be overly critical, so take all this in context.

I had Raymarine (E120, radar, AIS, Fishfinder, Autopilot) in my last boat.  Although my problems were small compared to other people's, I did have issues with devices dropping off the network.  Some reading revealed this to be a common problem, and some of my friends were seriously plagued by it.  Support from Ray was hit or miss, with a lot more misses reported than hits.  In nav gear, I'm looking for rock solid reliability, which seldom goes hand in hand with software, but I still want it.  Granted, all this was in the darkest hours for Raymarine.  The industry was in the tank and RM was in financial straights on the verge of bankruptcy and trying to find someone to buy them.  Their US headquarters were just down the road from me at the time and I indirectly knew a number of people who worked there and they were experiencing constant layoffs.  I've heard support is better now, but product breakages still seem to be high.  For these reasons, RM is currently below my cut line.

My current boat is set up with Furuno everything except AP which is Simrad.  I picked Furuno because I wanted something rock-solid, and Furuno had that reputation.  My Furuno NavNet 3D is 4 MDF12s networked together with AIS, Radar, Fishfinder, and Sat weather.  The AP and all other devices are on an N2K bus.  I also have MaxSea running on a PC which also connects to the NN3D network.  For those who might not know, the Furuno NN3D chart plotters all run MaxSea as well.  I think I have a straight forward configuration that does not push any limits.  The issues I have with it fall into 2 categories; usability, and reliability.  The usability issues can be worked around and lived with, but they grate on me every day.  Instead of being a daily pleasure, it's like I have a pebble in my shoe all the time.  If you are a Windows-turned-Mac-user, you know exactly what I'm talking about.  The reliability issues have not been hardware problems, but rather software problems.  Some are just poor design and implementation, and some are bugs that cause crashes.  Yesterday someone asked me what my complaints were with NN3D, and I'll post my response in a separate message a little later.

That said, and remembering that "the Grass is Always Greener" and the "devil you know...", Furuno  is at the top of my list, in pencil, teetering, for now.  Simrad and Garmin are the serious contenders to replace Furuno if I can convince myself that one is really better for my needs and desires.  And I'll emphasize this last part, because what matters to me may not matter to others.

I like Simrad for a number of reasons.  First, I think the stuff is well built.  All the AP gear that I have is well made, solid, with good fit and finish.  I also find it to be well thought out with clear menus, logical navigation, and well grouped commands.  The documentation is good, and everything has worked correctly.  All this extends to the plotters as well.  They appear to have all the requisite features, and the menus and controls are well organized and intuitive.  All the things that bug me about the NN3D work in a much more satisfactory way on the Simrad.  But there are still a number of things that I need to try first hand, and of course there are all the yet-to-be-discovered Simrad issues which I expect exist.

The down side of Simrad as I've discovered so far includes a few things.  First, there is no integrated companion PC nav software.  At a minimum I want a PC program where I can do route planning, create waypoints, etc. and easily transfer them to the plotter and back again.  I also want to have active nav data displayed on the PC when underway, including AIS.  Nav data is easy to interface over N2K, but AIS is more of a problem since there isn't a consistent standard for carrying it over N2K, so that part of integration may be an issue.  I also don't want to have to buy a different and separate set of charts for the PC and the plotters.  I know I would have to forgo radar overlay since every vendor's radar data is proprietary, but I can live with that.  This whole area needs much more investigation, and I'd welcome any tips from people who have done this with Simrad.  I have an older copy of Rose Point so I'll probably start there and see how far I can get.  Anyway, this is one aspect of Simrad where it's up to the owner to figure it all out.

Simrad uses stock Navionics cards, which I like.  Unfortunately, they only support Navionics, so I'd have to get comfortable that they provide best-in-class coverage for all the places I plan to go, including some pretty out of the way spots.  But if you have to be stuck with a single vendor, Navionics is one of, if not the best to be stuck with.

I'm also nervous about Simrad's support.  I bought a WR20 remote for my current boat and it was flakey from the get-go.  Support was OK, but very slow with a return for repair that took almost a month.  An in-warranty repair should be advance-replacement, and in fact I later read that Simrad advertises just that, but it wasn't offered to me when I had a repair need.  My other support incidents have been less than thrilling.  Not bad, but not confidence inspiring either.

As for Garmin, I know the least about them.  The couple of Garmin car GPSs that I have had I thought were garbage so I have a hard time taking them seriously, but owners seem to be thrilled and that can't be ignored.  They clearly are very serious about being a leader in Marine Electronics, and they have the resources to do it.  One down side that I will have to investigate very carefully is chart quality and coverage.  I think Garmin is the only vendor who locks you into their own charts.  Furuno has proprietary formatting and packaging of charts and you can only buy through them, but they are repackaged C-Map and Navionics so you know what you are getting, and you have two to choose from.  As far as I can tell, Garmins charts are all Garmin start to finish.  I need to be convinced that they can really support world-wide navigation.  For example, I want to see their charts of So. Georgia Is. and the antarctic peninsula.

Garmin also has no black-box plotter, but I'm not sure that's really a problem.  To me, the value of a BB is that you can use a big screen where the MFDs all top out at 12" or maybe 15".  But unlike others, Garmin has big MFDs so that might be just fine.  And I have no idea about companion PC software, etc.

So that's where my head is on all this.  Furuno is the default choice, but teetering.  Simrad is a very serious contender with Garmin a bit further behind, and Raymarine is currently below the cut line.

Monday, December 17, 2012

Boat Layout

And now for the less technical side of the boat decisions.... layout and other configuration options...

First, it's important to know how we use our boat since that drives many of the design decisions.  90% of the time, it's just the two of us on the boat.  Neither of our kids has inherited the boating bug, so they are only aboard on rare occurrences, mostly when we have a large gang aboard which is even rarer.  These usually take place around whale watch trips.  From time to time we will have another couples join us, and that makes up the other 10%.  With longer passages we expect the 10% time with guests to go up a bit, but we'll never be like a lot of people who always have a multitude of people on board.  The biggest manifestation of this is around the number and configuration of state rooms.

For our "normal" cruising, two staterooms is fine, just like on our current boat.  And a third is great for long passages where we may need to get some extra help on board.  Four we don't need.

Now let's talk a little about the N55/60/63 "family" of boats.  All three share a common hull, at least the forward 80% of it.  The N60 is a stretched version of the N55.  For the first few N60s that were built, the extra 5' was just an elongation of the hull section behind the rudder.  The keel was no longer, the prop position was unchanged, and the rudder position was unchanged.  In later models, the keel was lengthened and the running gear moved back in keeping with the longer hull.  If you look closely at the pictures on the Nordhavn web site, you can see examples of both the new and old underside.

On the N60, all the extra length appears in the cockpit and the boat deck.  The interior of the N55 and N60 are identical.  We really like the extra open space in the cockpit, and it includes room for a nice built-in seating area and table for outside dining and lounging.  On the boat deck, the N60 transforms a space cramped by a dinghy into a space for a larger dinghy with room to walk around and more easily carry kayaks and/or bikes.  This is what sold us on the N60, and it's a modest 5% cost increase over the N55.

Speaking of the boat deck, there is an additional extension that can be added that brings the boat deck almost completely over the cockpit.  As a sun non-worshiper, this was very appealing to me, and was the difference between an outside seating area that I would never use, and one that I would use regularly.  It also gains another 4 feet of boat deck up above, and that's a real prize.  With the boat deck extension, there is now room to stow the dinghy athwart ships on the extension, and open up the main boat deck as a lounge area even with kayaks and bikes.  It's another big bang for the buck.

On the interior, there are two layouts, and the only difference is in the forward stateroom and head.  For both, the master stateroom is midships.  Forward in the standard layout, there is a hall/study with a guest stateroom off to the side and a head forward.  The stateroom is on the small side and has a somewhat V-shaped berth - fine from one person, but two will be playing footsie.  And unless you value an office, it's a waste of space.    The alternate layout has a fully forward guest stateroom with a more conventional bed shape and head off to the side.  The office in an integral part of the guest stateroom affording more space to the stateroom, but requiring invasion of the stateroom to use the office space.

We went with the standard layout.  I value the office space, and need a place where I can work or be on a phone call without bothering others.  There is a sliding door which opens the guest room onto the office, so when the office isn't in use, the guests can enjoy that extra space like it was always theirs.  As for playing footsie, we figure if two people are sharing the bed then footsie shouldn't be a problem, and perhaps a benefit.

This explains why we picked the N60 and how we have set it up, but what about the N63?  The N60 and N63 share exactly the same hull, but have different above deck and interior layouts.  The N60 is a forward pilot house (FPH) design with the pilot house slightly forward of ship's center, and an aft boat deck.  The N63 is an aft pilot house (AFP?) with the pilot house about 70% aft of the bow and the boat deck forward.  On the N63 interior, everything flows forward on a single level (maybe a step here or there) with the same forward stateroom setup that's optional on the N60.  The big difference is that you can access the forward stateroom via a hall, where on the N60 you need to either go through the master, or go up to the pilot house then back down to the hall/study.  If stairs are a problem then the N63 starts looking pretty good.  There also is an argument (a valid one, I think) that the ride is better in the aft pilot house compared to the forward pilot house.  In general, the further aft in the boat, the better the ride in rough seas.  The N63 also forgoes the fly bridge.  We have gotten to a point where we only use our fly bridge in spectacular weather, so I don't place huge value on it, but when the weather is nice and you are whale watching or otherwise enjoying the sights, it's a pretty nice place to be.  The other thing the N63 has is a mini-cabin down in the laundry room, presumably for crew or kids.  Storage space is more important to us.  The forward boat deck has some advantages, in particular the ability to carry a larger dinghy, but it's not large enough to carry our 1965 17' Boston Whaler (which would be really cool, but isn't realistic), and the dinghy blocks one or more of the hatches.  Bottom line - we prefer the N60.

Other than picking from the standard option list, we have made what I gather are very few customizations.  I doubt it's more than a 1/2 dozen things.  I've learned that it's not uncommon for buyers to hire designers who specialize in boat interiors to set up the boat to their ideals.  And others hire marine consultants to help specify the equipment and machinery.  I don't know if this is the norm or the exception, but we have done neither.  Hopefully we won't regret it.  We have renovated a number of houses and become pretty good at spelling out what we want.  We are also fortunate that Laurie has a really good sense of space and visual appeal, and I have a good understanding of the systems and machinery, so we have the Ying and Yang covered and are not running blind.  We are by no means experts, but have a pretty good idea what we like and want.

One funny story serves as an example.  Selecting granite for the counters, etc. can be a time consuming, flip-flopping process.  When the time came, the PAE crew hauled out a container of samples for us to go through.  I pulled one off the top of the pile and said "There it is.  This is the one we want", and Laurie agreed.  They were dumbfounded.  What they didn't realize is that we had picked that same granite for two other houses and had already agreed we wanted to do the same thing on the boat.  The one we wanted just happened to be on the top of the pile, but even if it hadn't, we would have found it in a matter of minutes.  Call us boring, but we can pick out granite quickly.  The same goes for fabric, etc.  When in doubt, I defer to Laurie, and except for the Christmas-vomit sofa, she has never failed.

Back to the customizations, here's what we changed, or at least what comes to mind right now.  Most of these were inspired by changes made by the owner of the boat we toured.
  • We shrank a cabinet in the salon to make more room
  • We shrank the dining table in the salon to make more space
  • We shrank the galley sink to make space for larger drawers 
  • We added commercial-style door handles/locks to the fridge and freezer
  • We made the master bed a bit larger (we are both bigger than average)
As far as accommodations and living space is concerned, I think that's it.  It does, however bring up a tricky problem.  When looking at these boats, you have no idea what's standard and what has been modified by the person who commissioned the build.  Hopefully we won't get any surprises.

Oh, one other thing.  The standard boat comes with a bath tub in the master head.  A tub would only be usable  at dock or in an extremely calm anchorage without sloshing water all over the place, and the rest of the time it's in the way.  Plus, what a strain a tub would put on the water supply and hot water.   So we went with just a shower.

Thursday, December 13, 2012

Shore Power Conversion

Boats all have the ability to be plugged into shore power to run everything when at dock.  For boats that only travel in one part of the world, their shore power is set up for that particular region.  In North America, that would be 120/240V 60hz.  In Europe, 230V 50hz is the norm.  Other parts of the world follow one of these two standards, or variations on each.  The challenge for a boat that will travel all over the world is that it needs to be able to run on all the different forms of shore power, or at least some reasonable subset of them.  The question is, how?

If you really want to go all-out, there are companies that make universal shore power converters.  They take in whatever you give them, and put out exactly what you want.  But they come at a high price in $$, space consumption, heat dissipation, and complexity.  If for no other reason, the cost eliminates them as a possibility for me.

The other approach is to use boost/reduce transformers to match up the voltage.  This is a much more cost-effective approach, but it only matches voltage, not frequency.  60hz power will remain 60hz, as 50hz will remain 50hz.  As a result it's a partial solution, but for me, it will have to be close enough.  After all, firing up the generator is always an option to get exactly the power we want.  At a minimum, I want to be able to leave the boat in a foreign marina on shore power for extended time while we are away.  To do that, the bare minimum is to be able to run the HVAC so the boat doesn't become a Petri dish, keep batteries charged up, and run whatever alarm and monitoring equipment is on the boat.  Anything beyond that is icing on the cake.

Given all this, here's what I think we need to be able to handle for shore power, and what it needs to be converted into on board.

  • 120/240V 60hz shore -> 120/240V 60hz ship
This one is easy since it's the power that the boat is designed to use.
  • 120/208V 60hz shore -> 120/240V 60hz ship
This one is a bit trickier, and represents a 15% voltage boost.  For a variety of reason that I'll skip over, some marinas only have 120/208 shore voltage.  Given the way the N60 is wired, this turns into 104/208V on board.  Many appliances will work fine on this, but the lower voltage means that those appliances will draw more current than normal, and that means more internal heating, and possibly shorter life.  A 15% boost fixes this.

The cases above can be handled with a boost transformer.  Several different companies make them, and the transformer used on the N60 can be adapted to do this as well.  We have elected to make this feature part of our build so we can run on 208V shore power without stressing any of our electrical appliances.

50hz operation is a lot trickier.  Not only is there a voltage difference to deal with, but some 60hz devices can handle 50hz, where others can't.  This means that when plugged into 50hz power, we will only be able to run selective devices, and the list is short.
  • Hot water heater
  • Battery charger
  • HVAC
That's it.  All other 240V appliances like the washer, dryer, watermaker, and oven can't be used unless we run the generator.  120V appliances are fine because they all run off the inverter which will continue to operate at 60hz.  They key is to be sure the battery charger can keep up supplying all the DC power needed to run the inverter.  As a side note, the charger-feeding-inverter combination is a mini version of the bigger universal power converters that I talked about earlier on.

The above appliances will run at 50hz, but there is some fine print involved, including one little tid bit that was completely new to me.  The first bit of fine print is on the HVAC components.  They warn that when run on 50hz, their output is reduced by 17%.  OK, that's not a bad price to pay, and something I can live with.  But there is another more subtle part to the fine print.  It says they can be run at 200V 50hz.  Not 230V, not 240V, but 200V.  What's with that?  I started hunting around and found this article which explains it in more depth  The key is that if you reduce the frequency, you need to correspondingly lower the voltage or you risk overheating and burning out the motor.  Running the HVAC directly off 230V 50hz would appear to be really bad for the compressors and fans.

The solution to this obscure problem is to apply a voltage REDUCTION when operating at 50hz, intentionally bringing the voltage down to 200V - at least for the HVAC.  That will make it happy, and be operating it completely within manufacturers specs.

Although the HVAC wants to see 200V 50hz, the water heater and battery charger will actually be happier with the native 230V 50hz power, so ideally it would be nice to have both.

After a bunch of back and forth with PAE, their transformer manufacturer, and the HVAC manufacturer, we now have both a Boost and Reduce setting on our shore power transformer, and we have added a second transformer on the dedicated HVAC shore power connection so we can independently Boost/Reduce that power source too.  Operationally, here's how it works:

Rotary Switch 1 selects which ship's shore power inlet to use:
  1. Off
  2. 240V FWD
  3. 240V AFT
  4. 120V FWD
Rotary Switch 2 selects the Ships power:
  1. Off
  2. 20KW Generator
  3. Shore (Normal)
  4. Shore (Boost)
  5. Shore (Reduce)
Rotary Switch 3 selects the HVAC power:
  1. Off
  2. Ship's Power
  3. HVAC Shore (Normal)
  4. HVAC Shore (Boost)
  5. HVAC Shore (Reduce)
This lets us run off any combination of shore connections with Normal/Boost/Reduce, including different settings for the Ships power and HVAC if desired.  It's not prefect, but is a very affordable approach that gives us a lot of flexibility and I think will allow for use of most shore power sources around the world.

Wednesday, December 12, 2012


First, a little aside - we signed the contract today to build N6062.  Decoding that number, it means we are building a Nordhavn N60, hull number 62.  And now, back to hydraulics....

After having active fin stabilizers in our Grand Banks, I'll never consider a boat without them.  In fact, I don't know anyone who has had them who doesn't feel the same way.  N6062 will be no exception, and once again we are going with ABT/Trac.  Fortunately, ABT is the standard option for Nordhavns, so it was an easy choice.  I've had nothing but excellent experience with ABT and wouldn't consider anything else.

But this time, we are going one step further and including Stabilization at Rest, or STAR.  Historically, fin stabilizers only work when the boat is moving.  The fins work against the flowing water to counteract roll and hold the boat steady.  The slower the boat is moving, the less effective the fins are.  Once the boat comes to a stop, the stabilizers lose their effectiveness.  At anchor, they do nothing.  If you are in a rolling bay, you are in a rolling boat.  This situation is where gyro stabilizer manufacturers tout the advantage of a gyro - they help stabilize when the boat isn't moving.

However, a few years ago ABT got clever and figured out how to make the fins doggie-paddle while the boat is at rest in such a way to counteract roll.  Pretty cool, eh?  From owners I've talked to, it works pretty well, and we've decided to include it as an add-on to our stabilizers. Most of the equipment is already there with the basic stabilizers.  To add STAR, you need some extra brains in the control unit and some extra hydraulic controls.  And perhaps the biggest - you need hydraulic power while at anchor - which brings us back around to the hydraulic system as a whole...

Looking back at the basic stabilizers, they need to be powered, and the sensible way to power them is via a pump connected to the main engine.  Anytime you are underway the engine is running, so it's  a sensible place to get the hydraulic power.  But what if the engine fails and you have to run off the wing engine?  It sure would be nice to still have stabilizers, right?  From what I've seen, the most common solution is to put a second pump on the wing engine.  For the most part, it's a sensible solution, but there are a  few complications.  First, running the hydraulics takes power, and that's power that's not available to propel the boat.  Wing engines can only move the boat 5 kts or so, and robbing power for hydraulics will only slow things down more.  Often the solution is to up-size the wing engine, which is certainly an approach.  Remembering back to the previous post, the other gotcha with a wing engine is that it only has a puny alternator on it - about 40 amps - which isn't enough to run the electric power on the boat.  Remember, the main engine has a 175 amp alternator for house power.  If you are going to be on the wing for more than a short time, you need to run the generator for electric power.  With the generator running, it becomes another candidate power source for backup hydraulic power should the main engine fail.  With that, let's go back to hydraulic power for the STAR system.

Sitting at anchor, you will have occasion to run the generator, but no reason to run the wing engine.  And the generator is quieter with it's sound shield.  Putting all this together, we've decided to put the second hydraulic pump on the generator, not the wing.  This will give us both electric power and STAR when anchored.  Now keep in mind that we don't expect to run the STAR all the time we are anchored, but rather only when conditions demand.  But there is a price to running the hydraulics off the generator.  Just as it draws power from the wing engine, it draws power from the generator engine resulting in a de-rating of the AC power available.  Instead of 20KW we will only have about 12KW available to us.  For the most part that won't be a problem, but under some circumstances it will require management of the larger electric loads like AC, the oven, and dryer.

That covers stabilization, both underway and at rest, and power to keep it all going in a sensible way.  But on bigger boats, there are several other candidate devices for hydraulic power.  These are the bow thruster, stern thruster, and windlass.  The big advantages to hydraulic power for these devices is two fold;

  1. More power.  Hydraulic thrusters are 20-25hp where electrics are 15hp.
  2. 100% duty cycle.  Electric thrusters work well, but if you run them for more than a few minutes, they overheat and shut down.
This last point is the big concern.  If you are using your electric thrusters so much that they overheat, it's because you need them.  So by definition, when you need them most, they are most likely to thermal-out on you.

Given this, you would think hydraulic thrusters would be a no-brainer, but guess what?  They cost a small fortune - probably 2-3x the cost of electric thrusters.  After some initial back and forth, and to contain costs, I decided on electric thrusters and windlass.  My current and previous boats both have electric thrusters, and I've never timed them out.  In fact, I use then so little that they accumulate growth and by the end of the season up here in New England, they are nearly inoperative because of the crud on them.  This thinking lasted a few weeks, until I talked to a couple of owners who convinced me otherwise. One described a couple of situations where they really needed the thrusters, and sure enough, they thermaled-out.  The other consideration is that some things on a boat can be easily changed, added, or upgraded in the future, and some things can only be decided at build time.  Hydraulic thrusters fall more into the later category than the former, and is what finally tipped the scales in favor of a full hydraulic package.  In addition to the thrusters and windlass, the system also includes an anchor washdown and a high-capacity crash pump.  It's a painful hit financially, but I don't think I'll regret it.

With this last addition, it's worth looking back one more time at how the whole package is powered.  Thrusters use a LOT of hydraulic power.  As a first step, the pump on the main engine needs to be increased from 28cc to 75cc.  That's almost 3x the fluid flow.  But when you are operating thrusters, the engine will typically be at idle, yielding minimal flow from the pump.  That's one of the reasons the displacement needs to be increased so much, but it's still not enough.  Just the main engine can deliver enough power to run either thruster at full power, but not both at the same time.  To get the extra power, we will once again be turning to our generator, which will also get a more modest pump upgrade from 28cc to 45cc.  As a side note, this is where many boats choose to draw the extra hydraulic power from the wing engine.  When entering or leaving port, you fire up the wing and rev it up to 2000 RPM or so, and it provides the extra hydraulic power.  It's also a great way to ensure the wing gets regular exercise.  But given the need to power the STAR system, coupled with the need to run the generator anyway to supplement electric power when using the wing, we think the generator is the more sensible source for supplemental hydraulic power.

Another consideration in selecting electric or hydraulic thrusters and windlass, is fault resilience.  There is a good argument in favor or electric devices.  Each thruster and the windlass are separate devices, and a failure in one won't impact the other.  With hydraulics, if you lose hydraulic power, it takes out several important devices.  I spent a fair amount of time looking over the hydraulic schematics and discussing them with ABT, and ultimately concluded that it's a manageable issue.  In a later post I'll go through the whole failure analysis that I did on the boat, but focusing on the hydraulics, there are a few key points.  First, there are valves that segment off parts of the system.  This allows for containment of failures in a variety of ways.  Second, there are redundant sources of hydraulic power, so a pump failure is not the end of the world.  Third, the main hydraulic loop where a failure would take out everything, is entirely within the engine room and laz.  This means it's accessible for repairs.  My plan right now is to identify the hoses that would kill the whole system if they were to rupture, and carry spares.

So that's one more piece of the puzzle sorted out.

Monday, December 3, 2012

Engine Selection

I've been accused of writing a "guy" blog.  Well, yah, have you looked at me lately?  I'm a guy.  So to all my guy-friends, read on, this one's for you....

For a while I expect to be writing about the thought process and decisions that go into building a boat.  We have accumulated a bunch of experience over the years and have become clearer and clearer on what we like and don't like, but we've never built a boat before, so much of this is new to us.  Even on a "production" boat, there are still hundreds of decisions to be made.  Nordhavns are production boats, but they are built-to-order which means all boats are built for a specific owner, customized to their wishes.  I think it's safe to say that no two boats are the same.  I won't go through all the detailed decisions, but I think it will be both interesting and useful to others looking at different boats with different systems to hear about the tradeoffs and selections we are making.  But keep in mind that our decisions are only right for us (hopefully), and others will make different decisions.  Boats are an amazing exercise in trade-offs.  Nothing is free, either figuratively or literally (especially on a boat).  The trick is to find the right balance for your needs.

The first installment will be engines.  The actual choice of engines is easy because there is only one.  A large percentage of Nordhavns are powered by John Deere engines.  Many carry the name Lugger, but it's still a Deere at its core.  Lugger is a company that adapts them to marine use, and more recently Deere has started doing it themselves.  Deeres are widely used in commercial fishing boats and have a great reputation.  You don't hear a lot about them because they just keep on working.

The big question is whether to go with a single engine or twins?  Most Nordhavns have singles.  They yield a bit better fuel economy (order 10% in theory), represent one engine to maintain rather than two, and costs less.  The argument for twins is two-fold; better maneuvering in tight quarters like docking, and redundancy in case on engine fails.  The penalty is two engines to maintain and slightly worse mileage.

All the boats I've had prior to our Grand Banks have been singles, and I have to admit that I really like the meneuverability of the twins.  If you have been following this blog, you will recall this little incident where twins really saved us st-anne-de-bellevue.

But priorities on this boat are different.  Range matters, which means mileage matters, and for some reason the penalty for twins on this boat is much more than 10%.  It's more like 25%-30%, if not more.  That's a big price to pay, and has a big impact on range.  You can always slow down to regain range (fuel mileage is all about how fast you go), but the reverse is true too - the better mileage you get, the faster you can run on a long passage and still have the range to make it.  That last part I like!

But what about redundancy?  If an engine craps out, with twins you have another one to keep you going and get you home.  That seems pretty important, right?  Yes, it is important, but it's not that simple, and there are other ways to gain redundancy.  I like to break engine failures into three groups:

1) Fuel problems:  Many, maybe even most experts will tell you that fuel problems are the most common cause of engine failure.  You can take on a load of contaminated fuel, and a little time after you get underway, your engine dies.  Or you can be in rough seas and the inevitable accumulation of crud that has settled to the bottom of your tanks get stirred up and sucked into your engines and kills them.  There is a sound argument that a fuel-related failure will take out both engines, not just one, so having twins doesn't buy you any protection against this class of failures.

2) Accessory failures:  These are things like drive belts, alternators, pumps, impellers, etc.  If one fails, then it will indeed stop on engine, and only one engine.  A second engine will get you home.  Your other choice is to repair the problem at sea, which for many failures is very doable, and for others it's more difficult.

3) Core engine problems.  Here we are talking about major problem.  A shot injection pump, burned valve, broken mechanisms, etc.  Even McGiver isn't going to fix these problems at sea, so they make that second engine look pretty good.  But this sort of problem is VERY rare.

These are pretty compelling reasons for twin engines, until you consider another way to solve the problem; a wing engine.  A wing engine is a small, second engine who's sole purpose is to keep the boat moving when the main engine is off.  They can only move the boat at 5kts or so, but that's enough to keep the boat stable and heading in the right direction while you carry out a repair, and it can get you home if the main engine is unrepairable.  For this reason, wing engines are often referred to as get-home engines.  In addition, to protect against fuel-related problem, a wing engine is typically equipped with its own dedicated fuel tank that is filled through a filter to prevent contamination.  If you pick up a load of bad fuel, it gets filtered before going into the wing tank, and filtered again two more times before being consumed by the engine.  Wings are also equipped with folding propellers typically used on sail boats to minimize drag when not in use.  A wing adds cost, but not nearly as much as twin mains.

There is also a little gotcha with twins running on one engine.  If you lock the prop shaft on the failed engine, the stationary prop creates a lot of drag.  And if you let it freewheel, some transmissions will overheat and risk damage, and some shaft seals will overheat and risk failure.  On many boats you must lock the shaft, and how the heck are you going to do that?

But lets not forget maneuverability.  Twins give you quite a bit, especially after you get the hang of them.  You can spin the boat around in a circle in place, and with a little practice and the right rudder action, you can walk the stern to one side or the other.  Add in the bow thruster, and you can move the boat sideways in either direction.

With a single and the right rudder action, you can kick the stern to either side when powering forward.  But in reverse, the stern always pulls to one, and only one side - the rudder does nothing.  This is known as prop walk, and the direction it pulls depends on the rotation of the prop.  On Nordhavns, it pulls to starboard.  Our last boat was a single engine with bow and stern thrusters, which serves to compensate for the reduced maneuverability of a single.  But after I got used to it, I seldom used the thrusters at all - so little that by the end of the season they were completely ineffective due to marine growth on the props.  The key, though, is that thrusters can make a single just as maneuverable as twins as long as they stay clean and are powerful enough.  Stay tuned until another post for a discussion about what "powerful enough" means.

Can you guess what configuration we picked?  We are going with a single 325hp main engine, an 80hp wing engine, and both bow and stern thrusters.  It's worth noting that a bow thruster is standard equipment on pretty much all boats these days, including the N60.

Coming up next - stabilizers and other hydraulics

Saturday, December 1, 2012

A New Boat?

What's that you said?  A new boat?

Yes, despite postponing our trip south, our cruising appetite has grown considerably.  Not just our desire to cruise, but where we want to visit.  Over the past year or two we have been coming up with places we'd like to go, but 9 out of ten times they are unreachable in out current boat.  The Grand Banks is a really nice coastal cruising boat, but "coastal" is the key word there.  It has a range of 250 to about 600nm, which precludes getting to a lot of places.  It's also set up for daytime cruising, not 7x24 operation which is essential for any long passages.  The nav station, salon, and galley are one in the same.  Night operation requires heavily dimmed lights to preserve night vision, and given the way the boat is configured, that precludes any activity in the salon or galley.

In contrast, ocean-going boats carry significantly more fuel - 2400 gal vs 600 gal on the GB.  And they have a dedicated pilot house which is a separate room from which you operate the boat.  You can dim everything down in the pilot house for night vision, and not restrict activities in other parts of the boat.  Plus, they are build to take a lickin' and keep on tickin'.  Not that the Grand Banks isn't - it's an exceptionally well built, sturdy boat, but it has low sides, a low bow, and is meant to stay in port if it's going to be really nasty out.  In an ocean going boat, you are at sea longer than the weather forecast, so you need to be able to take whatever comes along.

Enter the Nordhavn, which is designed exactly for ocean going cruising.  The other thing that's really nice is that they are designed to be operated by a couple, with provisions for guest and crew as needed.  Almost all other boats over 50' are designed assuming they have a professional crew.  This means dedicate space for separate crew quarters, and a layout that allows them to move about the boat unseen by the owners and quests.  Nobody wants to see the house elves, or the seedy underbelly of the boat's workings, do they?  Egalitarian-me finds that quite distasteful.  Plus, I'm a geek.  I'm the first person in the engine room, every time.  The Nordhavns are set up assuming that 90% of the time they are operated by a couple.  And for the 10% where a hired crew is desired, there is room to accommodate everyone without compromise or imposition.

When I look back at our early exploration of boats, two stood out at the time.  Nordhavn and Grand Banks.  You might ask, "why didn't you get a Nordhavn to begin with?"  Good question.  The answer is "speed".  The Nordhavns are what's know as displacement hulls.  They push the water aside and flow along, but can only do so up to a certain speed.  If you have ever wiped out at high speed while water skiing, you know that water turns into concrete when you encounter it at high speed.  The same is true for boats as they move faster and faster through the water.  Pretty quickly the resistance of the water is like plowing through concrete.  It just doesn't work.  There are formulas that describe all this, and the bottom line is that a boats speed in "displacement mode" is a function of the square root of it's length at the water line.  The longer a boat is, the faster it can practically move through the water, but the length has to get longer a LOT faster than the speed goes up.  For a 50' boat, the top speed ends up being around 8kts.  That's not very fast.

In contrast, boats like the Grand Banks are built with planing hulls.  This means that as the boat goes faster and faster, it lifts up and starts to skim across the water, not just plow through it.  Once a boat is planing, it can go almost any speed as long as it can remain stable and not shake apart.  Our GB will do 22kts which is a LOT faster than 8kts.

Coastal cruising is typically hub-and-spoke cruising.  You keep the boat in some location (the hub), and each weekend (or longer vacation period) you hop on the boat and head out (the spoke) to make use of your finite time.  A fast boat makes a HUGE difference in how far you can venture from your hub, and can be the difference between new adventures and repeating the same old thing.  This is why we selected the Grand Banks over a Nordhavn.

However, our trip this past summer taught us about "linear" cruising versus hub-and-spoke cruising.  When you are on a linear voyage, it's all about the voyage, not about how far you can get in a day.   You are not trying to get somewhere and back in a limited time, you are on a quest.  And on longer cruises, you WANT to slow down, so speed capability is no longer a big deal.  On our nearly 3000 mile trip, I can count on one hand the number of days where we went fast.  Our conclusion?  Fast only matters if you are doing hub-and-spoke, and we are not doing hub-and-spoke.  And, we need ocean-going, long range to visit the places where we want to go.

What all this means is that we are in the process of contracting to build a Nordhavn N60.  As you can see from the picture below, it's as much a small ship as it is a boat, and the picture below that shows our current Grand Banks is comparison.

The N60 can travel well over 3000nm without refueling, can run 7x24, and has been proven over and over again as a go-anywhere boat.

Stay tuned for a number of posts about the whole process of detailing the boat, selecting options, trading off various things, and hopefully creating a boat that best fits our needs.

Cruising, Part Deux All Over Again

Most of you probably already know that we pulled the plug on our hasty plan to head south for the winter.  After a mad rush to get all sorts of things fixed on the boat in preparation for the trip, it became clear that we really didn't have enough time either to get the boat down, or to get it back in any civilized way.  We already had several fall commitments, the holidays, as well as commitments in February and May.  The trip down was either going to be a mad rush, or have to be broken into several segments with gaps in between to go home for other things.  Both options take all the fun out of cruising.  And the trip back wasn't looking too much better.  So we've decided to wait until next year where we can better plan around it.

The best part about this change of plans is that all the big boat projects are already done!  I've got a few little things to do over the winter, but for once there are no major projects.  The bright work is all spiffed up, another filer has been added to the water maker, we replaced the guest mattresses, did all the oil changes and other maintenance, installed prop cutters, etc.  It's nice to have all that behind me.  Tanglewood is out of the water and wrapped up for the winter.