Cherubini rudder support question

[kito]

I removed a stack of rotted plywood on my H30 that I am not sure if it was a PO rigged job or a factory install. It was on the top of the rudder post where the emergency tiller would be connected. The rudder post comes up to the bottom of the stern seat within an inch to the access port. It looks like they made 4 12" square pieces of 3/4" plywood with a hole in the middle for the rudder post and slid in one at a time and screwed one to another.....the first piece screwed into the fiberglass seat. The hole has clearance around the rudder post. Just wonder what the heck is this for? That post seems fairly sturdy plus the drilled holes in the plywood had a good amount of clearance around the post.

 

[GorillaToast]

Unless there is a plastic ring with a bolt thrus the diameter and the rudder post underneath the plywood squares, those are what are holding your rudder to your boat. I have a 27' and this is what holds my rudder in. After 35yrs service, it fell to pieces in my hands when I removed it.


I had a replacement made by a local plastics supplier for about $180.



There are no suppliers for this part. You have to have it custom made.

 

[ggrizzard]

Your description matches mine as factory installed. I guess it was the cheapest way to stabilize the rudder post at its head. Mine suffered some water ingress through the access plate which was caused by the rubber gasket losing seal over time. You can replace the gasket or the entire assembly. But you may want to reinstall your current plate with new sealant. I recommend butyl tape from Compass Marine, Maine Sail's site.

You might consider resealing the binnacle with butyl tape as well, as the seal is probably gone as well.

 

[kito]

Thanks GGrizzard. I will replace the wood and the access plate seal. I have 2 rolls of MS's butyl tape GT, thank you for the pictures. It looks like the 27 had a much better design than the 30 did in this area.

 

[SailormanDan]

There are no suppliers for this part. You have to have it custom made.

I had a whole bunch of work done on the drive train, so I can't tell you the exact cost, but the guy doing the work also had to fabricate one of these to replace the old cracked one.

 

[DianaOfBurlington]

I wouldn't replace that plywood but would make it out of G-10 or even koosa. In this way you eliminate the rot problem, which is primarily a problem of builders (like Hunter) and owners painting exterior-grade plywood with fiberglass resin and considering it 'saturated'. If they'd used WEST epoxy, that might have been something; but note that many of our Cherubini-designed Hunters were made before saturation epoxy was a big thing. My dad was the one who introduced WEST epoxy to Hunter as he had been using it to build ultralight-airplane spars.

My H25 rudder comes up through the seat (tiller-only boat) and the corresponding part on mine was bad too. Without even removing the rudder I lifted the old fiberglass plate and screwed it down on 5200. I then went underneath and tabbed the rudder tube to the underside of the seat. The only reason this wasn't done at the factory was in the interests of time. The rudder tube was 'glassed into the hull and the hole cut into the seat (part of the deck) prior to the deck's going on. The fiberglass plate on top of the seat, and the little blocks other people have observed, were added to 'trim off' the imperfect hole chopped into the seat (and my money is on no two boats' holes and plates being exactly alike). A seaworthy boat would definitely have this tabbed-in with only 'glass-- no plywood at all. There should be no opportunity for rot or leaks between the bottom of the rudder tube (in seawater) and the top of it, where either the tiller head or the quadrant goes, which should be as high as possible and heavily supported to the hull. Resolve this and the problem goes away for good.

That said, beefing-up the rudder tube itself with more 'glass, especially tabbing that spreads down onto the hull in all directions, is pretty much a no-brainer if you expect any serious sea time in any originally-cheap production fiberglass boat. My blog shows how I improved this on Diana.

BTW-- use of butyl tape for keeping out water or holding things down is not, by definition, in the interests of making a boat truly seaworthy. Sorry.

 

[Alctel]

I think the 36 sounds like the same arrangement - I also need to remove that piece.

 

[kito]

I wanted to make my new support from g10 but got kind of pricey. I decided to just use 3/4" plywood again. Each piece (4)was coated in polyester resin. No need for epoxy resin imo. The original lasted 36 years so let the next owner deal with it in 2052

 

[DianaOfBurlington]

Koosa is cheap, easy to work with in fiberglass, and sufficiently strong. Best of all it doesn't rot at all. I have a friend building a whole boat out of it. Compared to resin-saturated plywood, the weight is about the same or maybe even a little lighter.

My prediction for the industry is that koosa is going to replace wetted-out plywood for structural and laminating applications in which grain (unidirectional tensile strength) is not a factor, such as in decks and things like your rudder supports (especially in outboard-boat transoms!). And it will finally shut up all the noodniks who think Starboard is the answer for these things.

Get ahead of the curve-- do it now.