How to repair/reset fittings on Hunter 140

[sailorandpilot]

How do I repair/reset fittings on Hunter 140?

I just bought a Hunter 140 and the gudgeon plate needs to be remounted to the transom as well as a cam cleat on the stbd. side of the cb trunk. I am not sure of the construction of this boat, i.e. what is under the outer ACP skin. I was reading in the documents in the download library about fixing cracks with Devcon Plastic Weld. The six holes the screws go in in the transom are relatively intact, but aren't tight enough to hold the plate on. How do I re-do the holes and is that layer of caulk still stuck to the transom where the plate was, 3M 5200?

 

[mark2]

This looks similar to the construction of the H170 rudder mount. If so, behind the ACP is a layer of plywood embedded in structural foam, and behind that a layer of fiberglass. The screws are supposed to hold in the plywood, but if water has intruded the wood fibers are degraded and will not hold the screws securely.

If the plywood is not rotted you might be able to drill out the plate for a larger size screw and/or fill the holes with epoxy and re-drill them.

On our H170 none of that worked and we had to take more extreme measures by adding a backing plate inside the hull and using stainless steel bolts, washers, and nuts to secure the rudder bracket (see http://forums.hunter.sailboatowners.com/showthread.php?t=165887). I don't know if you can gain access to the backside of the mount area on the 140.

And yes, we used 3M 5200 to seal the bracket to the hull. After a full season our repair is working perfectly, but it was perhaps a bit on the extreme side!

Good luck!
-Mark

 

[Crazy Dave Condon]

Mark2

did your 170 come the dealer in Zebulon. If so, I closed the business and moved to Virginia. Good advice.

 

[sailorandpilot]

Mark,

I have looked over the repair to the Hunter 170 rudder you posted. That series of photos and the documentation of that job was very helpful. I also downloaded the repairing ACP document in the document repository at this site. One of those docs addresses repairing cracks to ACP with Plexus/Devcon Plastic Welder.

Would filling those holes with Devcon, re-drilling them, and re-installing the rudder plate as originally done be a good fix? Alternately, I thought of making a 1/8" SS plate to go on the cockpit side of the transom and drilling through and using 2 1/2" SS bolts and applying 5200 behind both plates. The transom wall is only 2" thick so getting inside is probably not an option.

Another suggestion is to drill the holes to about double the current size to use the rubber device in the picture. This rubber piece has a brass nut in the end that is inserted in the hole and when the bolt catches the brass nut, it compresses the rubber inside the hull and expands it. This would also create a space between the gudgeon plate and the boat by the width of that flange. I don't really like this idea, but would be willing to try it if the larger holes could be filled in with Devcon and re-drilled in the event it does not work well.

Please advise,

Jim

 

[mark2]

Hi Jim, I don't know if devcon is the right material to fill the holes. It is good for hull surface repairs because it bonds with the ACP skin but I don't know how well it would do bonding to the foam/plywood inside the holes. The prior owner of my 170 used some kind of epoxy but the repair did not last (and hence it became my problem!).

If you have only 2" to reach the other side I would recommend the backing plate solution. I am not sure if the plywood will ever give the strength needed once it has been compromised. If the hull is foam-core like the 170 there will not be any airspace in those 2 inches anyway, so through-bolts are the best option. If the backing surface is not very rigid then make sure the backing plate is large enough to spread the load and don't over-tighten the bolts or you may crack the ACP skin.

Good luck!
-Mark

 

[mark2]

Mark2

did your 170 come the dealer in Zebulon. If so, I closed the business and moved to Virginia. Good advice.

Hi Dave, I am not sure where the boat was originally purchased. We bought it in Raleigh from an individual via craigslist.

 

[Crazy Dave Condon]

Gents;

oringinally a block of wood or thick plywood was encapsulated into the hull or transom wall. I was not a fan of that at all. Why? When it got wet, that destroyed the wood. In addition the wood screws should not be used in attaching to the plastic or ACP hull material. In fact any bolts or screws going thru the white plastic as I call it with a thickness of 1/4 inch or less, those holes should be the same size of the bolt or wood screw to prevent cracking.

The only way is to put an inspection port and add backing plates once the inside is dry. I did suggest an alternative is to put injection foam in between the two walls and then thru bolt onto the outside or in the cockpit with a large aluminum plate. Use 5200 but lightly sand the exterior where it would go on to give good adhesion for caulking in this case.

He asked about injecting goop into the wood but the thing unknown is the condition of the wood but even then it will happen again down the road with the rudder. Been there as a dealer and done it.

 

[Sternstern]

Has anybody taken this project to a professional, if so who/where?

 

[Shorefun]

Some thoughts, I have a 170 and needed to deal with the motor mount.

First off a bit about the 2 part glue. It is methacrylate which is able to chemically get into the plastic to make a bond. The plastic they used on the hulls is smooth at the molecular level and does not bond with many glues. Even the 5200 has significantly less adhesion to it and 5200 can really stick to stuff. Plexus MA300 with mixing tubes and an applicator is a better purchase if you need to do any significant work. Plexus, Loctite and Devcon are 3 branches of the same company so they offer the same product in different packages.

So with my boat I went to put the motor mount back in place and found the screws just kept turning. If you look around the 170 section you will find people that have rebuilt the motor and rudder mounts. This will give you ideas on how to deal with the problem.

For me I decided to try GitRot epoxy. This can soak into 'dry' wood and make it stronger. I drilled a bunch of holes and poked in the epoxy. I also used wood dust I took from my miter saw catcher to fill the screw holes. I did this several times of the winter. I had to finish up last week when it got warm enough that the epoxy could cure. It seems I have fixed the problem as the screws came down tight. Really, only time will tell if any of the fixes really worked.

The reason I decided to try the epoxy and drill lots of holes was because I could poke a scribe in the holes and found some resistance telling me the wood was kind of still there (but not in the best shape). I also did some test drills to see what kind of wood came out. This may or may not work for you. My thought was try it and see. I could always cut it out and put in new wood.

One comment on the motor mount repair. The poster used 5200 to hold and seal the plastic down. I think I might have tried laying in some fiberglass using the MA300 to bond it all together. Keep in mind I can see nothing wrong with what was done. After seeing how the MA300 bonds I can see glassed backed and MA300 would be really strong structurally.

If you are going to pay someone to work on it be sure they know they MUST use the MA300 to bond the plastic.