Tuesday, March 29, 2011

System Design

This next installment of the back story will cover the system design.

There are a bunch of things that have to be sorted out when planning an installation. They include:

- Actuator location
- Fin size
- Hull reinforcement
- Hydraulic power (pump)
- Electrical power
- Transmission interlock
- Speed sensor/pickup
- Hydraulic cooling
- Location of control unit, valve blocks, diverter valves, control display, and hydraulic tank.

Actuator location: This was the starting point. For planing hulls, the fins should be within the center 20% of the water line. The location also needs to be accessible for installation and maintenance. On the 47' EU, there really is only one possible place which is all the way against the forward firewall in the engine room. The location is 1.5' forward of the LWL center, so it's a nearly perfect spot. It can't go further aft because the fuel tanks are outboard against the hull. So that locates the actuator for/aft, and is one stake in the ground. How far outboard the actuator goes depends on the fins, so we'll skip ahead to that

Fin Selection: Fin selection also impacts actuator location, so selecting the fin is required to finalize the actuator inboard/outboard location. The bigger the fin, the more effective the stabilizers are at lower speeds. The 47 EU can cruise at 20 kts, and has a top speed of 24 kts, but I want stabilization at a more efficient displacement speed of 6-9 kts. This drove the selection to a 6.0 sq ft fin rather than 4.5 sq ft. Both are fine at the higher speed, and in practice are expected to lower cruise speed by no more than 1/2 kt. 7.0 sq ft fins would have been an option, but the bigger the fin, the more the actuators need to be moved inboard, and the less effective they become. The key is to keep the fin inside the limits of the hull when they are centered. In other words, the fin can't protrude wider than the boat's beam at the water line so if you are against a warf, the hull is making contact, not the fins. And they can't drop lower than the draft of the boat. The 6' fins fit with bringing the actuators about 6" in from their most outboard possible location - not a bad tradeoff. The 7' fins were more problematic and forced the actuators much more inboard with possible interference with the engine stringers on the inside.

For reference, the past installations that I was able to track down on this model boat all used 4.5' fins. Part of the challenge was sorting out the impact of using larger fins, and whether there was a problem that I didn't know about. Luck has been with me, and it turns out Grand Banks is doing an TRAC installation now using larger fins, in fact their project includes stabilization at rest (STAR) which uses an even bigger fin than mine. It's the engineering for this new project that I'm shadowing which includes placing the actuators more inboard that jobs they have done in the past.

The other challenge with fin selection is making sure they clear the hull across their full swing. My boat has a chine at the outer edge of the hull, and the fins need to be trimmed to clear the chine. A side benefit of the more inboard actuator location is that less trimming of the fins is required. I'll lose about 1/4 sq ft off each. I'll be templating the fin, and TRAC will built it with the required notch.

So that nails down the fins, and finalizes the actuator location.

Hull Reinforcement: As I've mentioned previously, the reinforcement schedule is borrowed directly from Grand Banks on a nearly identical installation they are doing, and that one is based on several past installations that they have done. It involves relocating the stringer and building up the hull thickness between the new stringer, the ribs fore and aft, and up the side of the hull. This is the part I know I shouldn't do. I just stink at doing this type of work, and this is not the project to learn/practice on, so I'm hiring it out through my yard.

Hydraulic Power: The fins are run off hydraulics, and there are two ways to power it. A pump off one of the main engines, or an electric pump run off the genset. I'm not a run-the-genset-all-the-time kinda guy, so electric is out. Besides, the stabilizers only work when the boat is moving, and the main engines need to be running to make the boat move, so that's the obvious answer. Then the question is how to attach the pump. In my case the answer is easy. My ZF transmissions have provisions for a direct drive PTO. I've ordered the PTO kit from my local dealer, and the pump mounts to the PTO kit. One more stake in the ground.

Electric Power: The stabilizers run of 24V, so my package from TRAC includes a 12V to 24V power converter. I've got a spare 30A breaker and am ready to go.

Transmission Interlock: The stabilizers have a safety interlock that centers and physically locks the fins when either engine is placed in reverse. This requires picking up some signal when the gears are in reverse. My ZFs are electro-hydraulically controlled, and TRAC offers pressure switches as one interlock method, so that's what I opted for. I still haven't figured out what plug ot remove and replace with the pressure switches on the ZFs, but I'm confident I'll sort it out somehow. If anyone happens to know the ZF hydraulics, I'd welcome any help I can get. My backup plan is to tap into the electric control and use relays.

Sensor/Speed Pickup: The stabilizer control unit needs to know how fast the boat is going. If I could wave my magic wand, the control unit would take an N2K input and pickup the speed from the ships GPS, or if you want to be old-school, use NEMA 0183 to get the GPS speed. But my magic wand isn't working, so I have to install a rev pickup on one of the prop shafts. It's OK, I'll get over it.

Hydraulic Cooling: This one isn't 100% nailed down yet, but the current plan is to install an oil cooler in line with the engine raw water intake. TRAC wants the water temp to be 90 deg or less. My engine generates a 10 deg rise in the raw water, so in any kind of tropical water, outlet water temp will be too high, so I plan to use the intake water. TRAC is supplying a cooler with a 3" water aperture. Cummins (engine manufacturer) specifies a max intake restriction of 5 in Hg, and at sea trial they measures 1.2 in Hg. The specs on the cooler indicate it will add about 1 in Hg of additional restriction, leaving the total well below 5, so I think this will be fine. That said, I'm trying to get Cummins to give it the thumbs up, but haven't been able to corner them yet.

Location of Equipment: All the other "stuff" needs to have a home. I've gone through and put post-it's up where everything will go, and I'm pretty sure it will all work, but I want to have the equipment in hand to be sure. Once I have the locations finalized, I need to figure out all the cable lengths, and TRAC will make them all to length. Same with the hydraulic lines, except I'll have them made up locally.

So, I think that covers the system design.

Comments and discussion on this post:

lorenzo_b: Just put paravane stabilizers on my boat, all manual, built the swinging booms and fins myself with 2K worth of steel delivered from Miami. The winches were lots of fun to make. About two weeks of welding, 4 hrs a day. Total cost 3K.
That's one good reason to go with paravanes.

drpohl: I appreciate your preparation and plan but did you ask your previous surveyor for recommendations? Did you ask your insurance company regarding these major changes if they will require a re-survey and/or incline test/stability booklet by a NA? Whenever making major changes get it signed off from all the major players - before proceeding and after its done - sea trial and demonstrate to your and the surveyor's satisfaction.
Keep us advised on your progress and additional steps taken

askaer: Dear all Grand Banks folks out there!
What a wonderful and comprehensive sharing of observations and research on the stabilizer project at owner's own hand. I learned a lot. Currently I am having the very same work done on our 1year old GB 47 EU "ALMA" - hull #88 - read more about her at www.askaer.com. On recommendation by GB yard in Malaysia, I went for Trac 220 -6 with STAR using port engine as hydraulic pump PTO under way and electrical pump (generator on) during anchor, if needed. The procedure stated by you seems similar to mine and for the reasons of the many risks stated, and the fact that we keep the vessel in Singapore, we were grateful to GB that they offered to take the vessel back to the factory for the refit. It is currently at it's completion phase and next month we are going to try it all out. We are happy to report further at that time.
Super with this forum. All our best wishes and good luck.

Tanglewood: Glad the hear from you , Heine.

For others on the forum, it's Heine's installation at the Grand Banks factory that I am shadowing, so I'm very grateful that he's one step ahead of me and that Grand Banks has so generously shared their plans.

Back Story

Here's a little more of the back story.

I started investigating stabilizers right after buying the boat this past fall. As mentioned earlier, it's a 2009 Grand Banks 47' Europa with a 27 ton displacement. I considered Naiad, TRAC, Wesmar, and Quantum. Quantum said they had nothing for a smaller boat like mine, so that ruled them out. I placed initial calls to the other three and confirmed they could support the boat. Then I started looking for owner's reports to assess product quality, reliability, and company support. I also started getting quotes from yards and installers recommended by the manufacturers.

Although I didn't come across anything negative, I couldn't find many people using Wesmar. Naiad had mixed reviews. Mostly positive, but not all. For TRAC, I couldn't find anyone who wasn't completely satisfied. Given this, my first choice was TRAC, then Naiad, then Wesmar.

Then the fun began with the quotes. My thinking was to pick who would do the install, and keep the boat with them for the winter to give them a good winter job. People I had spoken to who had installed stabilizers in the past 5 years of so all said to expect an installed cost of $35k to $45k. All three vendors' equipment was about the same cost - $30k give or take.

I contacted Wesmar and they passed the lead to a yard in Maine, and they were prompt at getting back to me and providing a quote, but it was a jaw-dropper. $50k plus $13k for winter storage.

Naiad was helpful on the phone, and referred me to an installer, but I never heard boo from the installer so I concluded my job wasn't of interest to them.

TRAC was also very helpful on the phone and gave me a list of several installers. I found one marina on their list who was also a Grand Banks service yard, so I figured I'd try them. Getting a quote was like pulling teeth, which I consider to be a red flag. But I finally got it - $58k plus winter storage. Ouch.

At this point it was late October and winter storage was more important so I brought the boat to a local yard for the winter. This yard is fine with owners working on their boats, so it was a good match for me. In addition to the stabilizers, I had a full electronics refit to do, and having the boat 15 minutes from my house was pretty darn appealing.

In January, I got going again, and contacted Naiad again. This time they said they could do the install, which sounded pretty good. I got a quote for the equipment ($30K again), and arranged for them to come inspect the boat and quote on the installation. It took about 6 weeks to get them to see the boat, and a quote followed shortly behind. $56k plus I have to get someone else to do the glass work.

None of this was making sense. Everyone was saying it was about a weeks work for two guys, which is 80 hours. That's $8k @ $100/hr. Throw in some more for travel, hydraulic hoses, supplies, and I figure $15k should do it.

At this point, frustration kicked in. I would have to separately hire someone to do the glass work, and then pay $30k for someone to hang equipment, run hydraulic hoses, and wire things up. So I decided just do it myself, hiring a glass person, and handling everything else myself. I liked the design of the TRAC system better than Naiad's, and the installation process is very well documented and more forgiving than Naiad's. Also, every step of the way TRAC had been the most responsive with information, specs, drawing, etc. It was the most complete, detailed, and descriptive. I asked them if they could support me acting as the GC (general contractor) for the project, and they were fine with it. I also asked Naiad the same question, and never got a response.

The next day I placed the order with TRAC, and started working with my local yard to line up a glass guy.

Fiberglass Work Begins

The glass work is underway. A big chunk of initial work was masking off the engine room. All the cutting is done with a vacuum right at the cutting point, but this stuff still goes everywhere, so protection is critical.

Both stringers are now cut out, and have surfaced the first problem. You can see old putty oozing out of the joint. It was presumably used to set the stringer prior to tabbing it in. Getting all that cleaned out will be the next step and will add some time and $$.

Also below are a couple of shots of the equipment itself. The white castled disks are the base mounting plates, and the flat stainless disks are the outside backing plates. They are through-bolted together to form a sandwich around the hull. The main actuator then mounts to the castled plate. I'll try to get a picture of that later today.
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Comments and discussion on this post:

Osirissail: I think you are doing it correctly. Nautical Architects are no different than Marine Surveyors and other Marine "specialists". There are a few that know what they are doing and a lot that are politely put - less than knowledgeable and sometimes so full of themselves that they are a hazard.
- - Following what the actual boat manufacturer has done in similar installations is as close to the best way as you can get. And a reputable, knowledgeable MA would simply do the same thing - follow the manufacturer's installation - and charge you a great deal of money to tell you that.

capn_billl: I would focus on the reinforcement also. That will be key. On another note, did you look at the gyro stabilizers? Will you also be using paravanes? Are you planning any crossings?

Tanglewood: Yes, I have several reference boats including shop drawings from their engineering department.

My theory is that you get to choose the beating to get, but you don't get to avoid it. Maybe it's just me, but all too often I find that having work done by "experts" ends up being more work for me and/or results in a crappy job than doing it myself. More work because I have to go back to get them to correct mistakes and/or fix the other things they broke, and crappy job because too often "expert" shops have people doing the work who are not so expert.

We've probably all experienced this having our cars worked on, and it's been the story of this boat since I bought it used last fall. I'll spare you all the details, but all the "expert" work done on the boat after it was delivered from the factory, and that I inherited when I bought the boat, was a nightmare. Poorly designed electronics setup, bimini almost completely blocking forward radar visibility, grossly undersized autopilot, inadequate gauge wiring including a couple of distinct fire hazards, a washer/dryer installation that blocked closure of a seacock, etc. I've been fixing all that over the past month while finalizing the stabilizer plans and getting the fiberglass guy lined up.

Speaking of which, I've learned over the years what things I'm good at and what I'm not good at. Anything electrical or mechanical I can do - no problem. But fiber glass work, fine woodworking, car body repairs - forget it. I totally suck at it. I know this as the result of the aforementioned beatings, and realize it's better to give my wallet a beating on those projects.

Anyway, I'm going on. Everyone will have different risk tolerances and different appetites for taking on projects themselves. And this is a big project. I tried to hire it out initially, but the beating to my wallet relative to the work being done, and relative to my skills, combined to set me off in this direction. It will be interesting to see how I feel about it when I get to the end......

Tanglewood:  I looked at gyros, but rejected them pretty early on. The up-side with them is that they provide stabilization when at anchor. Fin stabilizers now have this capability too, but I did not go for it. My primary reason for passing on both is the need to run a generator all the time to power them. I've got a big stink-pot of a power boat, but when the end of the day rolls around, the sailor in me comes out. It's all batteries, inverters, LED lights, and a quiet night at anchor. A genset running all the time just isn't going to happen, so that ruled out any form of stabilization at rest.

The other issue with a gyro is the size. It would have completely filled my laz, and I need the space. My take is that they are a good fit for larger boats that have the space, and boats that have 24x7 genset operation anyway.

I don't have paravanes. Fitting them probably would have been just as much of a structural engineering project, and I get real nervous with large objects swinging around. Fin stabilizers of course operate on the same principal, but are active and not swinging from chains.

As for crossings, I guess it's all relative. Most of our cruising is in the north east US where 4-6 ft seas are quite common. We don't want to be stuck in port waiting for perfect weather. A "crossing" for us would be 40nm across Mass Bay, or 70nm from Gloucester to Portland. In both cases you can be 10+nm off shore with nothing in the way for 3000nm depending on wind direction.

Monday, March 28, 2011

Making Room for Actuators

This picture shows the work required on the hull. This is looking at the location of the starboard actuator, and the stringer is in the way. It needs to be cut out and rebuilt inboard about 10" or so where the hull is marked. The hull outboard of the new stringer will be built up with almost 1" of additional glass giving a total hull thickness of 1-1/2". The new glass will tie into the ribs and stringers on all sides for a real solid mounting location.

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Comments on this post:

dacust:  This will be interesting to follow.

drpohl: I always worry when I see a DIY project without the professional services of a naval architect - especially when vessel stability is involved.

Tanglewood: Me too. To address that, I've been working with Grand Banks, the boat designer and builder. They have done both pre-sales and post-sales installation of this exact stabilizer, and others, on this model boat. I'm shadowing exactly what they have done on these other installs, including the layup schedule for reinforcement, relocation of the stringer, buildup schedule for the new stringer, etc. The location etc also meets all of TRAC's requirements, in fact the actuators are almost exactly in their theoretically ideal location.

My bottom line thinking is that the manufacturer knows the boat better than anyone, and if I follow the engineering that they've done for an installation where they warrant the hull, then I should be in good shape. Is it risk free? No, but I feel pretty comfortable.

I'm curious how others see it? Too much risk

delfin: You'll find the ABT folks to be the best there are to work with, or at least that was my experience.

If you haven't had a NA specify the buildup for support, you should. Even though GB has opined, I would get an independent opinion. It won't cost much, and you'll know you have the hull properly reinforced, which on a glass boat is a survival issue on grounding.

kenny_chaos: Nice project.
I appreciate you sharing for the benefit of others but the benefit is usually
a beating for you. Good luck with that.
Anyways, do you have any reference boats?

Installing Stabilzers on a 47' Grand Banks

[Editor's note:  Sorry, the pictures for the posts on this project seem to be the wrong pictures, but if you click on them you will get the correct photo.   I'll try to get ti fixed shortly.]

Some time back I posted an inquiry about adding stabilizers to a 2009 Europa 47'. The project is now underway and I though others could benefit from seeing it in progress.

After several months of discussions with different stabilizer manufacturers, Grand Banks, and various prospective installers, I've settled on ABT TRAC 220 stabilizers with 6 sq ft fins. For installation, I'll be acting as general contractor myself, and working with my local yard to carry out the installation. Sorting out the installation was the most difficult part, with seemingly few people in the northeast who have any first hand experience with such a project, and project proposals that were over the top expensive, at least in my view. Finally, partly out of frustration, I decided to do it myself, contracting out the pieces where I need help. I'm in the middle of a complete electronics refit, so I already have things opened up and am pulling wires. Electrical work is no problem for me (I'm an electrical engineering by training), and I have lots of mechanical and hydraulic experience too, so much of the work is pretty straight forward. Grand Banks has been a great help in sharing drawings and specs for past installations that they have done, so that covers the structural engineering challenge, and does so with a reliable source. ABT has been a great help in specifying the product and working through various trade-offs, so about a month ago I pulled the trigger and ordered the equipment. While waiting for the first installment of equipment to arrive, I've been working through the final details for placement of the equipment, and working with my yard to get the fiberglass reinforcement work underway.

The next post will focus on the hull prep and reinforcement work that's required.