Need replacement Rudder...

[Jamiem]

This was my experience too, Jamiem, with a '69 rudder I cut open about ten years ago. It looked like hell on the outside, and while the foam was saturated and the metal was a bit rusty, it was really quite solid nonetheless. Not sure I would have crossed the Atlantic with it but it certainly would have had many more years of service had I not replaced (and destroyed) it.

The connection to the shaft is the concern now. If that is satisfactory I should be good to go. I do want to sail the Pacific and never glance aty rudder again. Any suggestions on weight of foam and source for reshaping the rudder?

 

[Jamiem]

The connection to the shaft is the concern now. If that is satisfactory I should be good to go. I do want to sail the Pacific and never glance aty rudder again. Any suggestions on weight of foam and source for reshaping the rudder?

I was guessing that 8lb epoxy foam would do the trick, but not sure on source in NW

 

[tenders]

Sorry, I have no game here - Foss Foam in CA sent me a nearly drop-in replacement for my rudder (with an up-to-date NACRA wing profile) so I didn’t spec anything out myself.

 

[Jerry VB]

Mads on Sailing Athena used Sicomin 250 (YouTube) with a density of 250 Kg/m^3.

 

[Nick J]

I was guessing that 8lb epoxy foam would do the trick, but not sure on source in NW

I used this stuff when I rebuilt the rudder on my 25+: https://fiberglasssupply.com/pour-foam/8lb-density-pour-foam/

 

[Martin King]

The connection to the shaft is the concern now. If that is satisfactory I should be good to go. I do want to sail the Pacific and never glance aty rudder again. Any suggestions on weight of foam and source for reshaping the rudder?

Well, when I owned a 39, I had Foss Foam (the one in California) build a new rudder. The OEM rudder is undersized for the boat. Foss foam had the original mold and they were able to extend it 12 inches. The deeper rudder made a big difference in how the boat handles and was a project well worth spending on. If you go this route, make sure you mike the bearings carefully and have them turn the new shaft on a lathe before the welding and subsequent glasswork.

 

[Christian Williams]

Jamiem, if you're heading offshore, a new rudder is one of the many upgrades for peace of mind. Strong forces out there. Worth the money.

 

[Mr. Scarlett]

Well, when I owned a 39, I had Foss Foam (the one in California) build a new rudder. The OEM rudder is undersized for the boat. Foss foam had the original mold and they were able to extend it 12 inches. The deeper rudder made a big difference in how the boat handles and was a project well worth spending on. If you go this route, make sure you mike the bearings carefully and have them turn the new shaft on a lathe before the welding and subsequent glasswork.

Martin, what kind of clearance are you looking for inside? I assume outside is snug - tapped in with a dead blow mallet.

 

[Martin King]

Martin, what kind of clearance are you looking for inside? I assume outside is snug - tapped in with a dead blow mallet.

Well in the case of the 39 there are upper and lower metal bushings glassed in to the hull/rudder tube. At this point, they may be egged out which is why I mentioned taking multiple inside readings with a micrometer. Usually these figures are then averaged and used as a starting point. As for clearances, I would leave that to the manufacturer to determine. You want it snug with no binding and no play.

 

[Jamiem]

Well, when I owned a 39, I had Foss Foam (the one in California) build a new rudder. The OEM rudder is undersized for the boat. Foss foam had the original mold and they were able to extend it 12 inches. The deeper rudder made a big difference in how the boat handles and was a project well worth spending on. If you go this route, make sure you mike the bearings carefully and have them turn the new shaft on a lathe before the welding and subsequent glasswork.

I was thinking about extending it, thanks for the info. Reverse has always been challenging so maybe this will help. Now I have a source for foam, approximate dimensions, all that is left is to get out there and do the job. Now if I can just get my work schedule to co-operate

 

[Jamiem]

Jamiem, if you're heading offshore, a new rudder is one of the many upgrades for peace of mind. Strong forces out there. Worth the money.

Totally agree. Also, knowing what is in the rudder and it's condition will allow me to make informed decisions. I have to say, whoever built this was not afraid to add steel. I really think the majority of my work will be cleaning, inspection and re-sealing. I think I got lucky that the boat was in Oregon, on freshwater, for the last 15 odd years.

 

[Mark F]

Hi Jamiem, Boatworks Today has a series on rebuilding a foam core rudder, https://www.youtube.com/playlist?list=PLV97GZkHhpHMfaW24ZBR-xitL-TN2si9A
Watching this gave me the confidence to rebuild/modify an old rudder I had for my 1976 E27. A big part of my confidence came from the fact that the rudder was a spare and if I ruined it, no big deal ;-). In the video Andy talks about using 18lb foam. I couldn't find that so I used 8lb.

 

[Jamiem]

I get the 18lb foam concept as it provides stiffness and also ensures the density of the overall rudder is somewhere around 1.0. In my case the steel core on the rudder is part of my justification to go to the 8lb foam. I did a quick calc and between that and the fiberglass the overall weight to volume ratio should be around 1. the challenge will be to ensure the extended rudder mentioned above (approx 12 inches) is bonded to the steel part properly. I will likely add steel to that section as well to ensure adequate bonding and strength across the rudder. The markup below will add approx 20% to the rudder area and reduce the torque required for steering as well. I still need to determine exact dimensions next time I am at the boat.