Dual Pilot Design?

[UNCIVILIZED]

Dockhead,
I think that the idea which you're pursuing is a wise one. But, it's all been done many, many times before. By folks who get paid a LOT to both design, & to "test" (in RTW races) such systems. That & by professional designer/sailors like the Dashews.
So emulating what's worked under the utterly torturous conditions encountered by the solo, Non-Stop RTW racers. Who circle the globe via the capes, would be a pretty safe bet. Ditto on borrowing bits from folks like the Dashew's. Who's solutions run towards equipment & system designs, using Commercial Marine gear. As proven by professional mariners, in multi-layered, redundant setups.


Oh, also, BTW. Please refrain from freaking out the newbies by giving them ideas of death by over-helming. They can always heave too for a few hours... or days. Put out a drogue, etc., etc.
Hundreds, if not thousands of sailors have made it safely into port/home, post self-steering failures. Or without having a formal system of it to begin with.


Back to these high end racers, & their AP setups:
One of the key things which many (or rather almost all) of them do, is to have multiple copies of the (completely) same autopilot onboard. Thus, you have full compatibility of spares. As well as the ability to cannibalize from one, in order to rebuild another.

Also, when I say multiple, I mean in excess of 3 (copies). There are plenty of said sailors, who go so far as to have 5+ pilots, even. And given the $ figures you're throwing around... likely you could spring for 3 or 4. Along with some of the key spare parts (read electronic brains for the units) too.
Albeit some of them will also carry a stand alone AP or as well. Which uses the same "brain" as their other units. Again, for commonality, & cannibalization, etc.

Plus, with that many pilots onboard, then one or more complete AP. Plus the fragile, electrical bits. Can be stored in fully WT, Farady boxes. As I alluded to before.
And if you like, it's easy enough to build a two layered Farady cage storage device. IE: One within another, seperated by electrically isolative materials.
Ditto on sealing your spares in plastic, prior to putting them inside of WT cases... like Pelican Cases, if you want the top end in protection.

As if a lightning bolt can jump from the sky, all of the way down to the water, it'll have little trouble jumping the gap in any switch, in a system that you set to the Off position.
And were it me, I'd be a bit careful with vacuum packing everything. As vacuum pressures can exert quite a lot of force on things which were never designed to be pushed on hard. Such as compressing a chip a bit too far into a circut board, for example (hypothetically). But the sealing in plastic thing, along with dessicant packs isn't a bad idea (especially when they're inside of a Pelican Case, too).

And if you're full on paranoid about lightning. Then look to the aircraft industry for their data on equipment testing. As well as isolating systems from lightning strikes of various quantifiable levels.
For if you've done much flying, commercially, I can guarantee you that you've been on a plane when it's been hit by one of "Thor's bolts". Likely sans much effect (or to your knowledge), thanks to said industry's R&D on the topic.

Regarding the failures of mounting points of AP rams. Knock on wood, the specifications of such things aren't usually laid out by yacht designers unless/until:
- You start to talk about boats which are really more in the way of small ships, size & expense wise.
- You specifically hire an NA or Engineer to design the system for you. One who's designed many such, successful, systems/installations, before.
So that he can calculate all of the forces involved, add in the appropriate safety factors (and then some on top of that). Followed by his delineating (in text, & blue prints/drawings) the materials & construction of said installations. Just as he would for a rudder, or any other, critical, technical system comprising the vessel.

On Wind Vanes:
I'd reckon that they'd work on a boat that size (they have before). It's just that you'll need a custom/semi-custom unit. Designed to match the scale of the vessel. And her performance characteristics.
As there have been a good number of boats in that size range which have had them in the past (& now). So, odds are, a little research will turn up some leads... probably to include some drawings to work from too.
That, & I'm thinking that some of the manufacturers of the gear which is out there already, would be happy to work with you as well; in fitting the right gear to said boat.

Likely the biggest sticking points in boats that big, & vane gear would be;
- Loads on the system:
Which is something that can be dialed down to reasonable levels via proper hull design shape (ie; a balanced hull form as she heels over), rig design & balance (plus of course, proper sail trim), & proper foil design & placement.
- What kinds of speeds the vessel will sail at:
As on something sailing at normalish speeds, vane gear will work okay. But on boats which rarely drop into the single digit speed range, the gear may not be able to respond quickly enough to steer the boat properly, in order to compensate for the rapidly shifting apparent wind.

FYI, 90%+ of all of the above, is Fully laid out in the Dashew's Cruising Encyclopedia vol. II And the majority of it is also well covered in the video tape which they put out at the same time as Vol. I of the same book.
Yeah, it's a lot of info (to dig through in their book - Great Stuff!!!), but if you want to build your systems in a way which has already been well tested... Then for $15USD on Ebay, the book's a dirt cheap investment. Plus a damned good read (and reference).
Although IMO, were it me, I'd just go to SetSail » Products & pick up all of their books for $70.

As there's hundreds of pages of stuff on ~ both boat design; big picture. And boat design; systems, in said tome. On all manner of the things you mention desiring in a vessel. And IIRC, there's even a dozen or two, pages on design/build contracts, etc.
Given that it sounds as if you're heading down that road.

Finally => RE; Hydraulic system ruptures. On any boat which has any hydraulic systems aboard (or just plain old diesel for that matter), you simply carry several bags of absorbent cat litter, or buckets of sand onboard. Well, that & a gallon or three of Simple Green (for de-greasing/cleanup).

As blowing a seal or hose on above deck hydraulics, turns things into a true horror show nightmare of a skating rink. The likes of which, you'll never forget if you've experienced it (such fun on 12m's, sans lifelines, in 25kts of breeze).
And even with one belowdecks, the oil has a nasty habit of migrating everywhere, including topsides. Ugh!


PS: Can we all please switch to decaf now ;-)

[Dockhead]

Originally Posted by Paul L

Dockhead
I don't think putting switches on the wires on the backup controller inside the Faraday cage is going to accomplish protection. You would need to disconnect the wires and not have them hanging out of the cage.

OK, thanks. I guess I will forget about lightning protection for the installed pilots, then, and just be sure to have a complete spare black box in spares.

[Dockhead]

Originally Posted by UNCIVILIZED

Dockhead,
I think that the idea which you're pursuing is a wise one. But, it's all been done many, many times before. By folks who get paid a LOT to both design, & to "test" (in RTW races) such systems. That & by professional designer/sailors like the Dashews.
So emulating what's worked under the utterly torturous conditions encountered by the solo, Non-Stop RTW racers. Who circle the globe via the capes, would be a pretty safe bet. Ditto on borrowing bits from folks like the Dashew's. Who's solutions run towards equipment & system designs, using Commercial Marine gear. As proven by professional mariners, in multi-layered, redundant setups.


Oh, also, BTW. Please refrain from freaking out the newbies by giving them ideas of death by over-helming. They can always heave too for a few hours... or days. Put out a drogue, etc., etc.
Hundreds, if not thousands of sailors have made it safely into port/home, post self-steering failures. Or without having a formal system of it to begin with.


Back to these high end racers, & their AP setups:
One of the key things which many (or rather almost all) of them do, is to have multiple copies of the (completely) same autopilot onboard. Thus, you have full compatibility of spares. As well as the ability to cannibalize from one, in order to rebuild another.

Also, when I say multiple, I mean in excess of 3 (copies). There are plenty of said sailors, who go so far as to have 5+ pilots, even. And given the $ figures you're throwing around... likely you could spring for 3 or 4. Along with some of the key spare parts (read electronic brains for the units) too.
Albeit some of them will also carry a stand alone AP or as well. Which uses the same "brain" as their other units. Again, for commonality, & cannibalization, etc.

Plus, with that many pilots onboard, then one or more complete AP. Plus the fragile, electrical bits. Can be stored in fully WT, Farady boxes. As I alluded to before.
And if you like, it's easy enough to build a two layered Farady cage storage device. IE: One within another, seperated by electrically isolative materials.
Ditto on sealing your spares in plastic, prior to putting them inside of WT cases... like Pelican Cases, if you want the top end in protection.

As if a lightning bolt can jump from the sky, all of the way down to the water, it'll have little trouble jumping the gap in any switch, in a system that you set to the Off position.
And were it me, I'd be a bit careful with vacuum packing everything. As vacuum pressures can exert quite a lot of force on things which were never designed to be pushed on hard. Such as compressing a chip a bit too far into a circut board, for example (hypothetically). But the sealing in plastic thing, along with dessicant packs isn't a bad idea (especially when they're inside of a Pelican Case, too).

And if you're full on paranoid about lightning. Then look to the aircraft industry for their data on equipment testing. As well as isolating systems from lightning strikes of various quantifiable levels.
For if you've done much flying, commercially, I can guarantee you that you've been on a plane when it's been hit by one of "Thor's bolts". Likely sans much effect (or to your knowledge), thanks to said industry's R&D on the topic.

Regarding the failures of mounting points of AP rams. Knock on wood, the specifications of such things aren't usually laid out by yacht designers unless/until:
- You start to talk about boats which are really more in the way of small ships, size & expense wise.
- You specifically hire an NA or Engineer to design the system for you. One who's designed many such, successful, systems/installations, before.
So that he can calculate all of the forces involved, add in the appropriate safety factors (and then some on top of that). Followed by his delineating (in text, & blue prints/drawings) the materials & construction of said installations. Just as he would for a rudder, or any other, critical, technical system comprising the vessel.

On Wind Vanes:
I'd reckon that they'd work on a boat that size (they have before). It's just that you'll need a custom/semi-custom unit. Designed to match the scale of the vessel. And her performance characteristics.
As there have been a good number of boats in that size range which have had them in the past (& now). So, odds are, a little research will turn up some leads... probably to include some drawings to work from too.
That, & I'm thinking that some of the manufacturers of the gear which is out there already, would be happy to work with you as well; in fitting the right gear to said boat.

Likely the biggest sticking points in boats that big, & vane gear would be;
- Loads on the system:
Which is something that can be dialed down to reasonable levels via proper hull design shape (ie; a balanced hull form as she heels over), rig design & balance (plus of course, proper sail trim), & proper foil design & placement.
- What kinds of speeds the vessel will sail at:
As on something sailing at normalish speeds, vane gear will work okay. But on boats which rarely drop into the single digit speed range, the gear may not be able to respond quickly enough to steer the boat properly, in order to compensate for the rapidly shifting apparent wind.

FYI, 90%+ of all of the above, is Fully laid out in the Dashew's Cruising Encyclopedia vol. II And the majority of it is also well covered in the video tape which they put out at the same time as Vol. I of the same book.
Yeah, it's a lot of info (to dig through in their book - Great Stuff!!!), but if you want to build your systems in a way which has already been well tested... Then for $15USD on Ebay, the book's a dirt cheap investment. Plus a damned good read (and reference).
Although IMO, were it me, I'd just go to SetSail » Products & pick up all of their books for $70.

As there's hundreds of pages of stuff on ~ both boat design; big picture. And boat design; systems, in said tome. On all manner of the things you mention desiring in a vessel. And IIRC, there's even a dozen or two, pages on design/build contracts, etc.
Given that it sounds as if you're heading down that road.

Finally => RE; Hydraulic system ruptures. On any boat which has any hydraulic systems aboard (or just plain old diesel for that matter), you simply carry several bags of absorbent cat litter, or buckets of sand onboard. Well, that & a gallon or three of Simple Green (for de-greasing/cleanup).

As blowing a seal or hose on above deck hydraulics, turns things into a true horror show nightmare of a skating rink. The likes of which, you'll never forget if you've experienced it (such fun on 12m's, sans lifelines, in 25kts of breeze).
And even with one belowdecks, the oil has a nasty habit of migrating everywhere, including topsides. Ugh!


PS: Can we all please switch to decaf now ;-)

OK, thanks for all of that.

What I take away from this is:

1. RTW racers do much the same thing as Evans and others have talked about, except that they keep a larger number of backups, and everything is the same for the sake of interchangeability.

That's useful, but it seems to me that this sort of confirms the design brief in my previous post, considering my requirements will probably not be quite as severe as a solo RTW racer, even if they are much more severe than the average coastal cruiser. Two fully operational, commissioned pilots, plus full set of spares. Check.

2. Hydraulic failures. What you write corresponds to my EXISTING practice -- I have a bag of cat litter and a few jugs of hydraulic fluid, and a complete set of spare hoses, on board my present boat. Just what I will plan for the next boat. I removed the hydraulic system which used to raise and lower my transom platform, so the only hydraulic system I now have is the pilot. Ditto for the new boat. I don't really like hydraulics and the potential for leaks, air in the system, etc., despite the many advantages. I spent time crewing a short handed (three sailors) Swan 90 which had extensive hydraulic systems, all driven by a single hydraulic pump on the generator. It seemed like bad system architecture to have such a significant single potential point of failure. Everything worked fine while I was on board, but it made me somewhat nervous. There was just no way in hell to get the anchor up or down, for example, if for some reason you couldn't start the generator, and I'm not even sure you could raise the fully battened mainsail of that size with a hand-cranked winch. Not only would you lose the windlass, but all powered winches would be down, if the generator doesn't start -- nightmare on such a large vessel. So for winches, furlers, windlass, thrusters, etc. I plan to do 24v electric systems like what I have now. I have multiple sources of electrical power -- it's a very robust architecture, and better than that Swan, I think.

3. Dashew's "Cruising Encylopedia" -- I bought this recently (they had a blow-out sale). I don't have it with me, but as soon as I get back to the boat, I will refer to it on these points. Thanks for the tip.

4. Lightning. I'm not really paranoid about it -- should I be? I thought to have key electronics spares in metal boxes -- is that not enough? I wonder if Evans has ever been hit by lightning in high latitudes?

5. Wind Vane. I have always heard that these just won't work on boats of more than about 50'. If that's not true, I'd like to know that. I wouldn't mind paying for a custom job if that's needed -- IF it would work. A wind vane is superb backup to an electro-hydraulic pilot, as it will work even if you have no power and no electronics of any kind. Even better, you get a complete backup rudder in the bargain (with the right design). If it would work on a vessel like this, I would do it in a heartbeat -- solving a couple of serious problems in a really robust way, in one shot.

[Dockhead]

Originally Posted by estarzinger

I had a handheld remote in addition to control head, which could continue to control the autopilot after the control head quit, but with less functionality (compass steering only, not wind or NEMA, for instance). When single handing I used the handheld 95% of the time. When Beth was on board we used the control head more.

The Robertson black box on Silk was mounted in a 'moist' place - not ideal. The B&G box on Hawk was in a very dry location (I do learn ) - but we did cruise to places where the 'environment' cycled quite hard - in chile the air would be cold and damp one moment and then we fire up the diesel heater and it would be warm and dry.

BTW on compasses - today - I would try to get two different solid state devices - a solid state inertial compass and a (3 antenna) gps compass - rather than the typical mechanical fluxgate.

Thanks, really useful!


Concerning compasses -- I haven't used fluxgate compasses in four or five years and never plan to go back. The new boat will have a satellite compass with Airmar H2183 (solid state, three axis stabilized) as backup, and a second Airmar H2183 in spares in a metal box. Good heading data is extremely important for not just pilot performance.

I don't know if I'm going to be far enough North for magnetic compasses to stop working, probably not, but that's another advantage of satellite compasses.

For spares storage, by the way, I plan to use gasketed steel military surplus foot lockers. Good Faraday cage plus rugged, waterproof storage.

[estarzinger]

The 2813 is a nice unit.

DARPA funded the development of a range of extremely small solid state intertial navigation systems. They wanted inertial systems, so that enemies could not "spoof" them, but the navigation speed and accuracy specs that Darpa set are significantly higher than in units like the 2813. These chips all really only became available for commercial use in 2013.. I think they now move the state of the art beyond the 2813.

This is not the best, but of the ones I have seen is currently the most plug and play for marine use . . . https://www.advancednavigation.com.a...specifications. It is a rapidly evolving area and marine applications are not where the money is.

I don't know anything about what is practically required for a real working Friday cage. Would not heavy tin foil, shrink wrapped, with decicant work for each part?

[Dockhead]

Originally Posted by estarzinger

The 2813 is a nice unit.

DARPA funded the development of a range of extremely small solid state intertial navigation systems. They wanted inertial systems, so that enemies could not "spoof" them, but the navigation speed and accuracy specs that Darpa set are significantly higher than in units like the 2813. These chips all really only became available for commercial use in 2013.. I think they now move the state of the art beyond the 2813.

This is not the best, but of the ones I have seen is currently the most plug and play for marine use . . . https://www.advancednavigation.com.a...specifications. It is a rapidly evolving area and marine applications are not where the money is.

I don't know anything about what is practically required for a real working Friday cage. Would not heavy tin foil, shrink wrapped, with decicant work for each part?

That looks pretty cool -- very compact and very good specs.

Among commercial marine products, I like these:

VECTOR LITE MKII - GPS Compass/Satellite Compass - True Heading AB

About $2300 in Sweden and doubtless cheaper somewhere else. 0.3 degrees dynamic heading accuracy, and 60cm (!) position accuracy.

No doubt there will be more, better, and cheaper satellite compasses on the market in the near future.

[darylat8750]

If the backup/second AP has a hyd cylinder I would want it installed and moving regularly. On 2 occasions I have had a cylinder drip at the seal after sitting unused for several months. I like to see the seals lubed by use myself. Airliners with mission critical components tend to use system A heading East and system B heading West or something like that.

[catmer]

Dockhead,

You mentioned you don't use fluxgate for 5 years,you know RM use Evolution Sensor very similar to ones mentioned here,I used in my new vessel though haven't tried yet,I wonder what you think about EV1

[olaf hart]

Great thread, thought I was the only person with an autopilot obsession.

Had a few pack up on me at sea and had to hand steer all night through a gale more than once, so my mind is pretty focussed on autopilot redundancy.

On a six ton 36' Joe Adams cutter, wheel cable steering with an emergency tiller, we have a

. Raymarine computer controlled wheelpilot, we are at close to the upper end of the size range but have had no issues with this boat which steers like a dream in all sorts of conditions.

. Raymarine linear drive system connected to the rudder shaft.

. Aries windvane

. Simrad tillerpilot for the windvane, actually two if I carry my spare

All systems are stand alone, and I carry a spare gyro.

I also have a seabrake which sort of steers on a bridle.