Raymarine St4000 with Trim Tab Problem

[atoll]

Originally Posted by Rustic Charm

Well, i took the day off work to go and test this new contraption. And I have some good news and some bad news.

The GOOD it works, in principle.

At least I can see its going to work. The problem is that it wonders up to 45 degrees. It helps with playing around with the rudder gain. 1 is nuts and its too slow to react. 5,6,7 and its starting to be quick enough in reacting but it then kicks the ram off the spigot. Ill post a video of this soon. But, i think it's just a case of playing around with a solid enough contraption, settings, and with distance out from the trim tab (what you guys called the positiveness i think) and also probably need to check the computers accuracy setting as it might be set on holding a strict course.

The BAD, is that making it out of ply on the trim tab end is simply not strong enough and kept bending in the wood. Then it just keeps falling out as you will see in the video.

But, i definately think this is going to work. The other thing I noticed is that if the boat is only going slow, it doesnt really work at all, but if im going at about 4 + knotts then it seems to work better, but again within about 45 degrees and then it swings back.

that's great ,it sounds like you need to up the response time ,if I remember correctly on the programmable raymarine AP'S there are 3 different settings you can adjust ie YAW,Rudder,and SEA STATE,sounds like you are just adjusting the RUDDER function,but need to be adjusting the YAW instead to stop it wandering.

once you have these 2 settings correct for your vessels idiosycracies ie RUDDER and YAW, then it is just a case of adjusting SEA STATE as waves get bigger.

as to it not steering when going slow,the trim tab works as a function of water flowing past its surface,so you either need to go faster or increase its surface area for more sensitivity/

[GILow]

Originally Posted by Rustic Charm

Yes it is Matt, this is Atoll's recommendation. And as it's moving with the ram, then the ram motion is the same as if i had it on the rudder, so I had to reverse the wires on the control head back to their origional direction.

Ah, OK, but that won't work with the little TP1000 if you go down that path later. The TP1000 has the compass built in.


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[Rustic Charm]

Originally Posted by atoll

that's great ,it sounds like you need to up the response time ,if I remember correctly on the programmable raymarine AP'S there are 3 different settings you can adjust ie YAW,Rudder,and SEA STATE,sounds like you are just adjusting the RUDDER function,but need to be adjusting the YAW instead to stop it wandering.

once you have these 2 settings correct for your vessels idiosycracies ie RUDDER and YAW, then it is just a case of adjusting SEA STATE as waves get bigger.

as to it not steering when going slow,the trim tab works as a function of water flowing past its surface,so you either need to go faster or increase its surface area for more sensitivity/

yep. Im pretty sure thats correct. I also need to program the rudder max stops. But, because im pretty sure this is going to work, ive ordered five new spigots and bushes for the ram end (they come in pks of 5). Im basically going to give it 4 different places. On both the ram and trim end to be placed. Because i kniw its going to work im going to go ahead and make a solid ss arm off the trim tab. Ill continue with the tiller thick ply end but ill aquadite the bushes in.

Then ill give it a good go at set up. Hopefully ill have a video up tonight.

[Snowpetrel]

Originally Posted by GILow

Ah, OK, but that won't work with the little TP1000 if you go down that path later. The TP1000 has the compass built in.


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Yep, your system is ideal for those all in one systems. But they dont tend to work well on a steel boat unless you can somehow raise them up high. Even then its hit and miss, depending on the magnetic signature of the boat. Ive also not had much luck keeping water out of them. Killed two units so far. The 4000 with its separate ram is much better.

RC, have you calibrated your unit yet by doing a few doughnuts? Also does it work if its fitted directly onto the tiller? Is it the 4000 or the newer 4000+?

Not a good day for testing down here, hope the weather is better up your way...

[Rustic Charm]

Originally Posted by GILow

Ah, OK, but that won't work with the little TP1000 if you go down that path later. The TP1000 has the compass built in.


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im going to go with a Pelagic as a backup actually

I did try a Simrad Auto Pilot for a while. It had the controls and gps built in. But as Ben suggested, the gps didnt seem to work very well on my steel boat, so i sold it just a few minths later and purcahsed a new TP4000Gp.

[Rustic Charm]

Originally Posted by Snowpetrel

Yep, your system is ideal for those all in one systems. But they dont tend to work well on a steel boat unless you can somehow raise them up high. Even then its hit and miss, depending on the magnetic signature of the boat. Ive also not had much luck keeping water out of them. Killed two units so far. The 4000 with its separate ram is much better.

RC, have you calibrated your unit yet by doing a few doughnuts? Also does it work if its fitted directly onto the tiller? Is it the 4000 or the newer 4000+?

Not a good day for testing down here, hope the weather is better up your way...

I havnt callibrated it yet no. I initially didnt think i needed too. But i clesrly do need to. And yes, it did work directly on the Tiller. I sailed it down from Adeliade with the same model and with my newest one been to Hastings, Wilson's Prom and Deal and back with it.

It was 'new' but obsolete model. TP4000GP.

[Snowpetrel]

Ahh, nice units, and a should be more than strong enough for your boat, being the GP model. How did the trip north go? Deal is sure is a lovely place isnt it.

[Rustic Charm]

Originally Posted by Snowpetrel

Ahh, nice units, and a should be more than strong enough for your boat, being the GP model. How did the trip north go? Deal is sure is a lovely place isnt it.

Wonderful trip that time. Cut short on the way back at Deal due to weather changing. We arrived back in the Tamar in 45knotts gusting 58. And it stayed that way for another five days, so it was just as well we called it quits at Deal. Deal is lovely, but on a nice blue day those islands across to Wilson's Prom are magical.

[atoll]

Originally Posted by GILow

Ah, OK, but that won't work with the little TP1000 if you go down that path later. The TP1000 has the compass built in.


Sent from my iPad using Cruisers Sailing Forum

here is how you get TP1000 with built in compass to work on a boat without a tiller,or with magnetic problems,by mounting the tiller pilot remotely.

[Snowpetrel]

Originally Posted by atoll

here is how you get TP1000 with built in compass to work on a boat without a tiller,or with magnetic problems,by mounting the tiller pilot remotely.

Thats a great system atoll, and it might solve the magnetic problems of a steel boat if you could mount it on the ceiling if a dodger or high on a targa bar.

One question I have with thise units though is that they must allow for the angle of the unit to change slightly as the tiller swings. Maybe they aren't that clever, but maybe they are? Still they seem to work ok when hooked up to a windvane so it obvously isnt a big issue either way.

What I do really like about this system is the way you can mount it out of the weather and somewhere handy.

The times ive used them hooked up to windvanes it was always awkward having to reach over the stern to tweak the course or set them up.

[atoll]

Originally Posted by Snowpetrel

Thats a great system atoll, and it might solve the magnetic problems of a steel boat if you could mount it on the ceiling if a dodger or high on a targa bar.

One question I have with thise units though is that they must allow for the angle of the unit to change slightly as the tiller swings. Maybe they aren't that clever, but maybe they are? Still they seem to work ok when hooked up to a windvane so it obvously isnt a big issue either way.

What I do really like about this system is the way you can mount it out of the weather and somewhere handy.

The times ive used them hooked up to windvanes it was always awkward having to reach over the stern to tweak the course or set them up.

here is another "Heath Robinson" system I built for a friend on her meta alu 40,which has a massive tiller,so not realty suited to using a small tiller pilot,though one the same as rustic charms probably would have worked,but the simrad WP100(wheel pilot) was what she had

wheel pilot was mounted on one side of the cockpit to its tensioning lever.
the drive belt was cut and a 6mm Kevlar line attached to the ends with a 50cm bit of 6mm chain at one end ,and led to a block on the other side of the cockpit,all roughly in line with the axis of the tiller and pulled tight and secured to the chain.

when in use you just centered the chain and belt and applied tension with the lever,set the coarse and slotted the chain into its bracket on the tiller.
worked a treat,and got her across the atlantic

rough sketch,as camera had run out of batteries as usual when I built it

[Snowpetrel]

^^ very nice Atoll, I love these sort of heath robinson setups. Might be able to resuse my old Wheel Pilot like that onto my windvane...

I also wonder if instead of using morse cable to attach an autopilot to a trim tab or servo rudder, you could use a single bit of 2mm spectra line with a bit of bungy cord on the other side to keep it tensioned? It might save some friction on some long runs. But probably no cheaper when you factor in good quality blocks.

[atoll]

Originally Posted by Snowpetrel

^^ very nice Atoll, I love these sort of heath robinson setups. Might be able to resuse my old Wheel Pilot like that onto my windvane...

I also wonder if instead of using morse cable to attach an autopilot to a trim tab or servo rudder, you could use a single bit of 2mm spectra line with a bit of bungy cord on the other side to keep it tensioned? It might save some friction on some long runs. But probably no cheaper when you factor in good quality blocks.

it would depend on where your trim tab is!
mine is 6ft down the transom about 10cm under the waterline

[GILow]

As suggested by Snowpetrel, here is a video of the version I suggest would be easier to build and install, while taking advantage of any A.I. programmed into the autopilot system.

My thanks to my son Ben for being the extra pair of hands needed for the demo. He got a bit of a buzz out of it, as being a trainee pilot and aeronautical engineer, he liked the idea of playing around with trim tab systems, very much a part of aviation engineering.

I have squashed the file down to 6MB, wmv format, apologies to those on limited bandwidth.

Matt

[Snowpetrel]

Damn GI. Cant seem to get android to recognize that compressed file. Even VLC viewer for andriod just goes blank on me... any tips?