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Siamese 05-23-2013 08:39 PM

Build Fiberglass Rudder
I have on order from Stuart Marine, a Mariner 19. This is the boat previously built and marketed by O'day. Definitely looking forward to it getting here so I can put it in my slip.

Because I'll be slipping it, I think I'll be wanting to replace the stock rudder sometime in the near future. The Mariner has the typical transom hung rudder for a boat this size. Wooden tiller connected to a sandwich of aluminum plates, gripping a mahogany rudder.

I'm thinking most Mariner owners who slip their boats, remove the tiller and rudder when not in use. What I'd like to do is replace the mahogany rudder with a rudder made of fiberglass, and coat it with the prevailing anti-fouling paint here on Lake Michigan, VC17, so I can just leave it on the transom all the time.

What do you think would be the handiest/best way to duplicate the rudder in glass, or should it be thinned down where it's sandwiched between the aluminum plates, and then covered with a layer of glass and resin?

paulk 05-23-2013 09:19 PM

Re: Build Fiberglass Rudder
To keep the new rudder from being overly heavy and still be strong enough, you will probably need to build it with a foam core. Unless you can live with a "barn door", shaping it to be hydrodynamic could be interesting without a female mould. All this to say that making a fiberglass rudder can be a hassle, and that's why they're so much more expensive than you think they should be. Using the mahogany rudder and replacing the wood when the time comes - five years from now, perhaps, if you keep it varnished and painted well, or maybe in ten years if (as you suggest) you fiberglass it - might be the simplest, cheapest, and easiest solution. K.I.S.S.

Jeff_H 05-23-2013 09:36 PM

Re: Build Fiberglass Rudder
I would think that it would be easier to carefully grind the wooden rudder and then glass it with epoxy and glass. Plan B would be to make female molds for each half using the wood rudder as a pattern, then glass the halves together. Plan C would be to make a blade from foam core material that you hot knife to shape then sheath with epoxy and glass.

Faster 05-23-2013 10:28 PM

Re: Build Fiberglass Rudder
Not sure of the overall cost but another option might be to talk to these guys or someone like them: Ľ Standard Rudders

Depending on your DIY 'gene' strain this could be an option...

rivorsaylor 05-24-2013 08:56 AM

Re: Build Fiberglass Rudder
Last year I built a new rudder for my Catalina 25. The old one was in bad shape and not a balanced rudder. I found dimensions for a balanced rudder and decided to try it. I started with 2 pieces of 3/4" marine plywood epoxied together. Then I laid out the profile and cut it out. I used a router and wood planer to shape the foil. Then came 4 layers of fiberglass cloth (more in the high wear areas). A few more coats of epoxy and some fairing, she was ready for paint. The whole project took me a few months to complete (working on it here and there when I could), but the rudder works great. The balanced design is like having power steering. I learned some new skills and bought a few new tools for future projects.

FirstCandC 05-24-2013 11:08 AM

Re: Build Fiberglass Rudder
Is that a Mariner 2+2? Nice looking boat!

rhr1956 05-24-2013 12:55 PM

Re: Build Fiberglass Rudder
Apply 3 or 4 coats of epoxy and then paint on the VC17

Alex W 05-24-2013 01:17 PM

Re: Build Fiberglass Rudder
It looks like RudderCraft (used to be IdaSailor) sells a kick-up rudder for this boat for $599, including a tiller.

They CNC their rudders out of HDPE plastic. Splitting is never an issue and they are fairly light and have a nice profile.

If you don't need the kickup feature it would be worth asking them for a price quote on a fixed rudder. I'm guessing it would get inexpensive enough that I personally would look for other projects (but I don't especially like working with fiberglass).

Siamese 05-24-2013 09:05 PM

Re: Build Fiberglass Rudder
Thanks for the replies. Coating the existing rudder would be the simplest alternative, especially if the saturation type of epoxy was used. Probably last a good long time.

I had thought about the the mold approach. Would make a nice rudder albeit at greater effort, but still possible.

The HDPE plastic idea is interesting, and I'd also wondered about Starboard (maybe not strong enough?). With a plastic rudder, I wonder whether VC17 bottom paint would stick...or even eat it up. I emailed Rudder Craft and inquired. Seems like it couldn't be too hard to make a plastic rudder with jig saw, grinder, and belt sander. Or, what the heck, if paint won't stick to it, maybe the stuff that grow in lake michigan won't either.

Siamese 05-25-2013 09:38 AM

Re: Build Fiberglass Rudder
Rudder Craft said:

Yes, we recommend VC17 and Interlux CSC as two paints that work well with our rudders."

That makes the HDPE an interesting option.

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