Raymarine St4000 with Trim Tab Problem

[Snowpetrel]

Ha, wrote a long post that said a similar thing to atoll, but the CF gremiln ate it... all sounds like a good plan. I'd be inclined to make the trim tab tiller a little longer than needed (maybe even out to 250mm or so), on the basis that it easy to shorten and hard to lengthen. If you curved the arm on a 620mm radius it could use the same base hole for any length of tiller arm. Ive used a 6mm bolt with a bit of tape over the threads as a pin in the past. That might be an easy way to get a number of pins that you can hook the ram onto so you can quickly trial a few lengths to find the best setting.

Id just bugle screw a hunk of timber onto that crusty old tiller you have and drill a couple of holes in it for the base pin of the ram to drop into.

I wouldnt glue the fancy raymarine bronze bush in until you know it all works. And you can build that fancy new tiller to suit it perfectly.

[atoll]

Originally Posted by Snowpetrel

Ha, wrote a long post that said a similar thing to atoll, but the CF gremiln ate it... all sounds like a good plan. I'd be inclined to make the trim tab tiller a little longer than needed (maybe even out to 250mm or so), on the basis that it easy to shorten and hard to lengthen. If you curved the arm on a 620mm radius it could use the same base hole for any length of tiller arm. Ive used a 6mm bolt with a bit of tape over the threads as a pin in the past. That might be an easy way to get a number of pins that you can hook the ram onto so you can quickly trial a few lengths to find the best setting.

Id just bugle screw a hunk of timber onto that crusty old tiller you have and drill a couple of holes in it for the base pin of the ram to drop into.

I wouldnt glue the fancy raymarine bronze bush in until you know it all works. And you can build that fancy new tiller to suit it perfectly.

yes +2 on making lever a bit longer,and 6mm bolts work fine for the pin,and hate it when the gremlin strikes

[Rustic Charm]

Well, today I managed to briefly test the system with the rudder gain turned down to one and it made no difference at all. So, on Tuesday I'll take the top of the trim tab tiller off and the rudder off and bring them home and set it up as Atoll has suggested. I need this sorted out in the next couple of weeks as I'm heading off to Melbourne around the 14th and I certainly don't want to be hand steering all night.

[atoll]

Originally Posted by Rustic Charm

Well, today I managed to briefly test the system with the rudder gain turned down to one and it made no difference at all. So, on Tuesday I'll take the top of the trim tab tiller off and the rudder off and bring them home and set it up as Atoll has suggested. I need this sorted out in the next couple of weeks as I'm heading off to Melbourne around the 14th and I certainly don't want to be hand steering all night.

don't forget to take the ram!
also you might want to leave the ram in its halfway extended position for easy measurement when you set everything up.

[Snowpetrel]

Rc, issume the system worked properly attached directly to the tiller? Just checking you dont have a magnetic problem due to steel near the fluxgate? I am supprised turning the rudder down from 5 to 1 didnt make any improvement, but then you do have some pretty nasty negitive feedback at the moment.

[Rustic Charm]

Originally Posted by Snowpetrel

Rc, issume the system worked properly attached directly to the tiller? Just checking you dont have a magnetic problem due to steel near the fluxgate? I am supprised turning the rudder down from 5 to 1 didnt make any improvement, but then you do have some pretty nasty negitive feedback at the moment.

I don't believe so no. Last week it worked as it should with the ram directly onto the main rudder. I would think that wouldnt work either if it was the fluxgate compass.

I moved the FG up onto the mizzen a couple years ago improve the compass.

[Snowpetrel]

^^ :thumbup: thought it was worth checking since Ive had them do weird things due to something magnetic nearby. Sounds like thats not the issue then.

[Rustic Charm]

I'm making a rough plywood (20mm thick) mount for the ram end. It won't last long, but hopefully long enough to test it and to do a crossing to Victoria in three weeks. Ill make a whole new rudder on my return once i know its going to work.

The trim tab end ill add a permament piece of 316 stainless, something like 20mm wide by 5mm thick. Ill have three holes in it for three different positions. I have a nipple for the ram that bolts on, so ill use that one on the trim tab end.

I sure hope this works Atoll

[Snowpetrel]

Thats the spirit, crude is good, now dont go spoiling that awesome waterworld effect by painting it!

I love the tex screws. A masterfull touch...

And just in case you think I am taking the micky, anybody who has seen my various boats will know I am being actually being half serious. I love crude makeshift solutions that work. Its a great way to mock the yachting establishments fettish for shiny fancy expensive bling. Kind of like how Bernard Motessier used to say life is too short for splicing wire, so he used a bunch of big crude bulldog grips on his rigging wire instead.

The flip side is that the joke only works, if it works. The steampunk lashup has to be at least be a seamanlike solution to a problem, ideally its much better than the equivalent shiny bling.

My pet peeve is yachties who put up with crap systems and layouts because it looks good.

[Rustic Charm]

Originally Posted by Snowpetrel

Thats the spirit, crude is good, now dont go spoiling that awesome waterworld effect by painting it!

I love the tex screws. A masterfull touch...

And just in case you think I am taking the micky, anybody who has seen my various boats will know I am being actually being half serious. I love crude makeshift solutions that work. Its a great way to mock the yachting establishments fettish for shiny fancy expensive bling. Kind of like how Bernard Motessier used to say life is too short for splicing wire, so he used a bunch of big crude bulldog grips on his rigging wire instead.

Well the roofing screws are just temp holding it down as i arodited it on to the post. I'll put a couple of botts through it for my trip.

But im contrmplating making a new pretty rudder out of marine ply glued together and then shapped. I think the ply would look nice once i sanded it and varnished it. I suspect it woukd be strong wouldnt it?

[Snowpetrel]

I assume you mean tiller? If so plywood isnt really the right material due to half the fibres running across rather than along the tiller making it very weak. Better to grab a nice chunk of knot free tas oak or any other durable and strong straight grained timber from the a hardware store and plane it down to shape.

If you get a severe affliction of yachties disease you can laminate a couple of different timbers together to get a fancy two tone look or nice curved shape, but the grains should all run along the tiller.

Or just get a nice chunk of gavanised pipe

My ultimate tiller would be a section of stainless pipe with a telescoping section so it can be shortened or lengthened. Ideally in its longest length you could sit under the dodger. But in good weather with a full crew you could shorten it right up to free up space in the cockpit.

[Rustic Charm]

Originally Posted by Snowpetrel

I assume you mean tiller? If so plywood isnt really the right material due to half the fibres running across rather than along the tiller making it very weak. Better to grab a nice chunk of knot free tas oak or any other durable and strong straight grained timber from the a hardware store and plane it down to shape.

If you get a severe affliction of yachties disease you can laminate a couple of different timbers together to get a fancy two tone look or nice curved shape, but the grains should all run along the tiller.

Or just get a nice chunk of gavanised pipe

My ultimate tiller would be a section of stainless pipe with a telescoping section so it can be shortened or lengthened. Ideally in its longest length you could sit under the dodger. But in good weather with a full crew you could shorten it right up to free up space in the cockpit.

Yes tiller, wasn't thinking.

I thought laminated would was exceptionally strong? Thats why you can purchase building beams now that are laminated and the specs for size is much smaller than a solid beam. Though, marine wise, i have no idea if its the same thing.

A stainless one was my preferred option . Not sure how strong it would be telescopic? . I like the idea of operating it from under a dodger

[Snowpetrel]

The laminated beams that kind of look like plywood are all laminiated with the wood grain running the same (or nearly the same) direction along the beam, unlike pkywood that has the grain running (normally) at 90 degrees to each other.

The engineered wood beams normally get the extra strength from not having any major flaws such as knots, and not having the same possibility of the grain splitting. They are also much more stable and less likely to warp, bow or check. But they use potentially mildly toxic glues, so it isnt all perfect.

I dont think there is a good reason why a telecopic tiller needs to be any weaker. I guess the end portion might be a bit weaker, but thats not where they are highly loaded. If they were built and designed right I think it could work fine, but its not as yachtie as a nicely varnished tiller.

[Rustic Charm]

Originally Posted by Snowpetrel

The laminated beams that kind of look like plywood are all laminiated with the wood grain running the same (or nearly the same) direction along the beam, unlike pkywood that has the grain running (normally) at 90 degrees to each other.

The engineered wood beams normally get the extra strength from not having any major flaws such as knots, and not having the same possibility of the grain splitting. They are also much more stable and less likely to warp, bow or check. But they use potentially mildly toxic glues, so it isnt all perfect.

I dont think there is a good reason why a telecopic tiller needs to be any weaker. I guess the end portion might be a bit weaker, but thats not where they are highly loaded. If they were built and designed right I think it could work fine, but its not as yachtie as a nicely varnished tiller.

cheers. I guess if i make a Tas hardwood one it will match my cowling around the cockpit.

[atoll]

Originally Posted by Rustic Charm

I'm making a rough plywood (20mm thick) mount for the ram end. It won't last long, but hopefully long enough to test it and to do a crossing to Victoria in three weeks. Ill make a whole new rudder on my return once i know its going to work.

The trim tab end ill add a permament piece of 316 stainless, something like 20mm wide by 5mm thick. Ill have three holes in it for three different positions. I have a nipple for the ram that bolts on, so ill use that one on the trim tab end.

I sure hope this works Atoll

no reason why it should not work,as long as the ram is in the middle stroke length,and port/stb sense is correct.

probably want the AP on its lowest response setting,and trim tab at 15 cm to start with