Autopilot connecting pin

[daletournier]

Hi all, on my recent passage I had some quite heavy beam on seas for a while. Snapped the pin that connects the linear drive to the tiller attached to the rudder post.

I have the St7000+ type 2 Raymarine linear drive.

The pin I can buy from Raymarine is different from the one I have. The photo below I lifted of the net. My pin is the same as the bigger broken one.

Are these pins inter changerable? The thread above the tiller that the nut is on is smaller but I don't believe this matters as it purely serves to hold the nut nothing more (I think).

Have only just started enquiring, anyone have experience in this area?

BTW Hydrovane is made by God, steered perfectly for 800nm passage, wish I never engaged the Raymarine briefly.

Thanks in advance.

Cheers Dale.

[sailah]

That pin would take any machinist 30 minutes to make. Pretty simple turn and thread, drill for cotter. Just bring in the old one and walk out with a new one.

Just an option if the one available doesn't work for you.

[Paul L]

If the thread diameter is smaller than the previous hole, then I think it will be significantly weaker and not a good replacement.
If it's any conciliation I've heard numerous tales of the Ray bolts breaking on passage.

[daletournier]

Originally Posted by sailah

That pin would take any machinist 30 minutes to make. Pretty simple turn and thread, drill for cotter. Just bring in the old one and walk out with a new one.

Just an option if the one available doesn't work for you.

This is true UNLESS your in a foreign country where you don't speak the language and you give it to a local mechanic at the yacht club 3 days ago who happens to be a massive pot smoker that has since disappeared. Apparently he goes into dope smoking hypernation at times, something I find out after would... Lol. All part of the adventure!!

[RaymondR]

I would say that the reason the broken one broke is that it's poorly designed. If you need to get a new one machined up I would make the upset section as short as possible and the thread as short as possible commensurate with being able to properly tighten down the nut. I would not use one with a smaller bolt as the bigger one has already fatigued and failed in service.

[Jim Cate]

If you get one machined up, you might consider using something other than 300 series stainless for the material. 2205 duplex s/s is quite a bit stronger than any 300 series, and has far better corrosion resistance as well. Or one could consider using non-stainless steel and using grease or other coatings to keep rust away. Have the machinist make carefully radiused corner roots to avoid stress risers.

REmember that Ray marine hasn't designed for longest life... more to the maximum profit so you shouldn't try to follow their lead exactly.

Jim

[daletournier]

Originally Posted by Jim Cate

If you get one machined up, you might consider using something other than 300 series stainless for the material. 2205 duplex s/s is quite a bit stronger than any 300 series, and has far better corrosion resistance as well. Or one could consider using non-stainless steel and using grease or other coatings to keep rust away. Have the machinist make carefully radiused corner roots to avoid stress risers.

REmember that Ray marine hasn't designed for longest life... more to the maximum profit so you shouldn't try to follow their lead exactly.

Jim

Hi Jim, I agree, this is my plan BUT at the moment I'll settle for what ever they can do it in, I'd prefer it not be ss.

It's 180nm to Madagascar, I'm then there for four mths, I'll work on the best solution then.

My guy has emerged from his pot smoking coma and is now on the job.. [emoji3]

[Suijin]

It should be fine if it's the same diameter. Looks slightly improved over the old one as it's a bit shorter and so subject to less sheering force.

I'd go with it, but I'd buy two

[Time2Go]

On a recent passage to Cartagena Columbia
the same thing happened to us.
Except we were on a big cat
The pin on port side sheared off
leaving the port side rudder free
The AP ram was also on port side.
The connecting rod with the sheared pin
was still tied to the ram but completely free
from the quadrant , driving the starboard rudder.
We stopped the boat and drilled a 1/4” hole
in the sheared pin and a corresponding hole
in the bit still in the quadrant.
We then stuck a 1/4 “ bolt (head off)
into both holes and hammered the thing together
We then lashed and tie wrapped it vertically.
The next 200 were interesting to say the least.
In Cartagena we found a local machine shop
and had a new part fabricated
Drilled and tapped the quadrant and all was good
New part was bigger
See pictures

[Time2Go]

Oops
Forgot pics

[Time2Go]

I also want to note that this was not cheap
Good machinists with good equipment
know what they are worth, especially to
foreign flagged 45’ cruising catamarans.
There was also a bit of hydraulic pressing
to be done on the tie rod fitting.
We also had to buy the proper drill bit
and tap. We did manage to borrow a proper
corded drill
Cheers
Neil

[Time2Go]

If any here are interested in
Machining parts and machining in general
check out
Abom79
on youtube, you will learn a lot more
than watching sailing blogs
This guy actually makes stuff
and explains it well
i have no affiliation
Cheers
Neil