The NSO is Simrad's top-end black box chart plotter and multi-function device. These issues were all encountered in their V2 software. Here's what I ran into:
CPA and TCPA is not calculated and often blank for AIS targets. Sometimes no data shows at all. But if I go to Coastal Explorer and look at them, all the info there and CPA and TCPA are calculated fine, so the AIS device itself is working fine and putting all the data on the N2K bus. Simrad told me this is a known problem that is fixed in the next release. They just released version 3, so perhaps this has been fixed. The pictures below show the problem. These happen to be the radar screen, but if you drill down on any of the targets, you get the same results.
In the first picture you can see that the first target, "Destiny", shows SOG and COG which is info included in the ship's position report coming from the AIS receiver. But CPA, TCPA, RNG, and BRG are all missing. These values are calculated (or not in this case) by the NSO. The second two targets are fine.
|Missing critical AIS info|
The next picture shows the problem again, but now there is no data at all other than the ships name, and even that appears to be jibberish. Note that the first target is a MARPA target, and only the second two are AIS targets.
|Missing critical AIS info|
The next problem also relates to AIS processing and display. The targets are supposed to be sorted by either CPA or range. So the targets we see listed here should be the most dangerous. But these appear to be in a completely random order.
The NSO provides a way to change the instance number on N2K devices. It's a nice feature, and easy to use. But depending on how you work through the steps, when you finally give the OK to make the change, the NSO gets stuck forever "Configuring device". I worked out the exact procedural steps to reproduce this and gave them to Simrad. Fortunately, if you hit the Cancel button you can recover from this.
This issue will appear twice, once here under the NSO, and again under the Auto Pilot bug list since both products are party to the problem. The issue is that depending on the sequence in which you power up the NSO and the autopilot components, the AC12 auto pilot computer becomes forever un-discoverable. More particularly, if you start up the NSO first (turn on breaker and push the pwr button so it boots up) before you power up the AC12 (turn on it's breaker), the NSO will not discover teh AC12 and will alarm saying there is no auto pilot computer. Furthermore, if you power up the AP controllers by pressing their PWR button (they get power from the N2K bus, so there is no dedicated breaker) after they boot up they alarm as well saying there is no AP computer. At this point, you can power down again adn back up in any order and neither the NSO or the AP controllers will be able to find the AC12. It's like it's been disconnected. HOWEVER.... if you cycle power on the N2K bus, then turn on the breaker to the AC12 before turning on the NSO, it recovers. And as long as you power on the AC12 before the NSO, it will continue to work fine. But is at any point you forget and power on the NSO first, it again locks up.
OK, there you have it for the NSO EVO II.
You haven't told us how you kept your sanity and your cool throughout all this. I am quite certain I would have lost it by now if I had spent all that money and ended up with this pile of dangerous rubbish.
The lesson for me is that it could be better to buy stand-alone equipment that doesn't attempt to talk to any other equipment. My current boat has just a Raymarine C80 Plotter with radar overlay and a back-up Furuno GPS. They don't have to talk to each other; they are independent devices.
Anyway, I wish you luck with the next stage.
I have enjoyed reading your blog from start to finish. It almost reads like fiction where there is always something about to happen around the next corner - a real real page turner :-).
I appreciate your in depth technical descriptions. I wasn't aware that there is both a relative and true mode for the motion vectors using MARPA targets. I have used NN3D True vectors quite a bit to look for potential collision course vessels. The newly acquired targets always seem to start off pointing the wrong way, but eventually straighten out to a stable path at least with NN3D.
As a previous owner of a Grand Banks 47 very much like yours I am curious how you would compare and contrast the "ride quality" and other significant differences while out in some of the lumpy stuff, or even in calm waters. I would love to hear your thoughts ( I'm possibly thinking of a Nordhavn in the future sometime...)
Thanks for the compliments, and glad you are enjoying the blog.
I didn't know about relative and true motion vectors either. But when the ARPA vectors on the Simrad radar were so whackey, I started reading everything I could find and came across relative vs true motion vectors. For a while I thought that explained why the Simrad vectors generally point off at an angle different from the AIS vectors, but that turned out not to be the case. And it certainly didn't explain the vectors swinging around.
I noticed the problem initially because of my experience with the Furuno NN3D radar, which is just like yours. While it's acquiring the target it will be unstable, but once acquired it tracks really well. For a while I thought maybe I was miss-remembering how the Furuno radar worked, but then got back on my Grand Banks to take it up to Maine for the winter, and it worked just as I remembered.
In the next week or two I'll have the new radar operational and will take a few videos to show how radar is supposed to work.
There are lots of differences in the ride between the GB 47 and Nordhavn 60. Here are a few:
- The GB is a planing hull where the N60 is a displacement hull. On teh planing hull the bow rises as you go faster, where the displacement remains level at all speeds. The resulting interior comfort while underway goes hands down to the N60.
- Both boats are stabilized, so roll is almost non-existant on both.
- Heading into waves, their size and approach speed are key. The approach speed is a function of the wave's own time period, plus you speed and angle making way into them. If you are head into them you will have the fastest closing speed, and the more of an angle at which you approach, the lower the closing speed. Long, slow swells are not uncomfortable at all. Where things get uncomfortable is when the boat is going up and down rapidly, and that's a function of how frequently you encounter each wave, and how tall the wave is. One rule of thumb is to avoid waves where the time interval and wave height are the same. If the interval is lots longer than the wave height then you aren't getting thrashed around as much.
This is a really long way to get around to my point. With a faster boat you have more choices in how quickly you close on the waves. I have found many situations where going a bit faster turns an uncomfortable up and down motion into a more comfortable bump bump bump as you more quickly bridge each trough and cut into the top on the next crest.
But overall we prefer the ride of the full displacement boat.
Good point about being able to go faster and skim over the waves a bit more. I have been out on smaller boats where going faster is much better than slower into lumpy seas - the bump, bump bump is more comfortable as you say although I have wondered about overall hull integrity giving all the thumping. I am guessing that the N60 would just punch through smaller stuff that would cause some bumping on the GB
I think I saw mention on a trawler forum about building a Nordhavn and a link to your blog from there. I don't remember what I was searching when I found that link, probably something about Nordhavns.
Nice talking to you today. It is good to see an N60 in person. The extra cockpit area is really nice and the extra overall length seems to give the boat a more streamlined look.