rudder, glass or wood?

[jbarros]

Hi agian,

I''m afraid my rudder is starting to go, and it''s time for a replacement. Now, I''ve seen the issues with glass over wood, so I''m thinking either painted wood, or solid glass. What disadvantages are there to glassing a solid rudder with no wood core?
What would you guys do?

Thanks.

-- James

[Irwin32]

Wow. I would start by checking the Good Old Boat web site for past issues where this may have been done. Modern rudders are not solid glass, but built with a stainless frame that is built off the post, with a foam core, and then a fiberglass skin. I am not sure how to make one, but this is the construction that seems to be the standard one.

[Jeff_H]

With all due respect nothing you are suggesting makes sense to me. There just about is no such thing as a ''solid glass rudder''. Most are foam rudders with glass skins and a stainless steel or composite rudder post and internal structure. If weight is not important, it is pretty easy to build a plywood outboard rudder and if you sheath it in a laminate of epoxy and fiberglass it will last for an extremely long time.

Painted wood will not be as strong or as durable as either of the above and solid glass would be obscenely heavy with no real gain in strength.
Jeff

[jbanta]

It would also help to know how your rudder is hung. Wood might work well if it''s hung over the transon out the stern of the boat. If it''s under well....Why again do you need to replace it? Can''t you refinish it? I am a great one for singing the praises of Apoxy. I don''t believe there isn''t too much on a boats wetted surfaces can''t be repaired with a bit of fiberglass and apoxy to get a smooth surface.

[Jeff_H]

JBanta is right. Assuming that the rudder post and internal structure is still in intact, it is not all that difficult to reskin a rudder with epoxy resin and fiberglass cloth. Essentially you either ground down a layer or so through the existing cloth or else peel off the existing cloth if it is delaminated and fair the core and then reglass. That is by far the easiest way to go if the existing rudder is still intact.

Jeff

[phunter]

Keep in mind the goal of nuetral bouyancy.

[Jeff_H]

Actually you want to be heavier than neutral buoyancy so that the rudder won''t float up.

Jeff

[phunter]

Actually, Jeff neutral bouyancy means exactly that. It does not float up (that would be called positive bouyancy) and does not sink (that would be called negative bouyancy). It just stays at whatevever level it happens to be.

Paul

[Jeff_H]

You actually want the rudder to sink. With neutral bouyancy wave action will cause a neutral buoyancy rudder to float up. The convention when I was designing boats was that the rudder clearly wanted to be heavier than water. At least that was how it how the textbooks and boat building traditions recommended designing rudders.

Jeff