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Bottom of boat hole

Flieger

Member
Hi all,
i'm attempting to replace the old-style rudder with a new one. In the bottom of the hull, where the bottom plate was attached, is a hole. What would be the best way to patch this up?

Thanks
 

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L&VW

Well-Known Member
West Systems "Six-10" is an epoxy-in-a-cartridge that is viscous enough to repair that hole with a minimum of sanding/preparation. (Hope that's a coin to show scale, and not a hole). :(

"Thixo" is another cartridge product with similar characteristics.

Just mix some up, drip into the hole, and sand fair with the hull when set.
 

Webfoot1

Active Member
If you're going with a new style you will be installing a inspection port in the deck to mount the rudder bracket? Glassing over the hole from the inside using the inspection hole is usually standard.
 

Flieger

Member
West Systems "Six-10" is an epoxy-in-a-cartridge that is viscous enough to repair that hole with a minimum of sanding/preparation. (Hope that's a coin to show scale, and not a hole). :(

"Thixo" is another cartridge product with similar characteristics.

Just mix some up, drip into the hole, and sand fair with the hull when set.
That's a quarter for scale reference. I'll take a look at the 610.
 

Webfoot1

Active Member
Use a tapered grinding stone to counter-sink the hole from the outside. Clean up the inside
and apply a strip of glass matt and cloth. When dry apply fiberglass filler to the hole on the
outside. Easier than when you next try to put the aluminum backing plate in. Due to excess
epoxy and junk on the inside you will probably have to cut the backing plate a little shorter.
Well worth it for the newer rudder system. It's a 100% improvement.
 

signal charlie

Well-Known Member
Staff member
So it depends on what is going on inside and how much work you plan to do? If the old wooden backer block for the latch plate inside the hull is in good shape you can leave it there and use it as a backer for the thickened epoxy, injected from the outside. In the photo below you can see the fiberglass strip that covers the wooden block and holds it in place. If the backer is mushy or gone then you need to cut or pry away the old fiberglass block cover and apply a strip of fiberglass cloth inside to act as a backer for the materials listed above. Make sure to buy the proper gudgeon backer, the one with the hump in it.

backer plate.jpg

We have not had to trim the internal gudgeon plate but I can see how that is a possibility. It might be easier to trim leftover fiberglass bits inside the hull to get the right fit. Leave the port off until the work is finished and tape over the raw fiberglass edge of the hole to save you skin.

image.jpg

Rudder Conversion steps

IMG_4076.JPG
 

Flieger

Member
Use a tapered grinding stone to counter-sink the hole from the outside. Clean up the inside
and apply a strip of glass matt and cloth. When dry apply fiberglass filler to the hole on the
outside. Easier than when you next try to put the aluminum backing plate in. Due to excess
epoxy and junk on the inside you will probably have to cut the backing plate a little shorter.
Well worth it for the newer rudder system. It's a 100% improvement.
Which fiberglass filler do you recommend?
 

Flieger

Member
If you're going with a new style you will be installing a inspection port in the deck to mount the rudder bracket? Glassing over the hole from the inside using the inspection hole is usually standard.
So it depends on what is going on inside and how much work you plan to do? If the old wooden backer block for the latch plate inside the hull is in good shape you can leave it there and use it as a backer for the thickened epoxy, injected from the outside. In the photo below you can see the fiberglass strip that covers the wooden block and holds it in place. If the backer is mushy or gone then you need to cut or pry away the old fiberglass block cover and apply a strip of fiberglass cloth inside to act as a backer for the materials listed above. Make sure to buy the proper gudgeon backer, the one with the hump in it.
Would the 3M Bondo 422 be a good rapair kit?
 

Sailflow

Active Member
I would clean out as recommend. Clean with acetone and fill with marine tex. That is a non stress area. Marine tex sands nicely.
 

wjejr

Active Member
Hi Flieger, I would use epoxy resin rather than Bondo which is a polyester resin. Epoxy is better for repair work.

I use MAS which uses 2:1 proportions making it easier to mix small amounts. I’ve also used System 3 and West and they are both fine, although West epoxy can get VERY hot when it kicks off. I believe Jamestown Distributor also sells epoxy under their own name, and that likely it is good. All of the epoxies just mentioned have been used to build boats that have sailed across oceans or boats that go 100+ around buoys, so the choice is yours.

Hope that helps.
 

Flieger

Member
Hi Flieger, I would use epoxy resin rather than Bondo which is a polyester resin. Epoxy is better for repair work.

I use MAS which uses 2:1 proportions making it easier to mix small amounts. I’ve also used System 3 and West and they are both fine, although West epoxy can get VERY hot when it kicks off. I believe Jamestown Distributor also sells epoxy under their own name, and that likely it is good. All of the epoxies just mentioned have been used to build boats that have sailed across oceans or boats that go 100+ around buoys, so the choice is yours.

Hope that helps.
Would this kit be sufficient for the small repair? Jamestown Distributors
 

Wavedancer

Upside down?
Staff member
Yes, MarineTex is your friend (around $20). I have used it a lot to repair daggerboards. Your repair will be 'plenty' strong.
 

Flieger

Member
So I finally patched that hole. After some brainstorming, I decided to cut a small piece of aluminum, and glue it into the hole with marine tex. From the underside I made sure that the marine tex squeezed out evenly, and then I leveled it off.

I haven't done a bona fide leak test, but visually it looks sound.

BTW: What was odd, is that the wood block that held the old rudder bottom plate was completely gone. Before I got a hold of the boat, there were no inspection ports, so I have no idea what could have happened to it.
 

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