Repairs and upgrades for Hammerhead

thataway · Posted: Fri Jan 01, 2021 1:23 am Post subject:

The water does not "leak" thru the laminates. I have seen a couple of boats where there was actually enough damage form osmosis to scrap the boat. I saw one high end yacht go form XXXXXX before survey go to XX after survey. This boat was in the Med.

I have owned boats with blistering/osmosis. But it is extremely rare. in the C Dory line. In Europe it was mostly boats laminated in the Baltic and brought to the warmer waters in the Med. Most of the cases I have followed were in S. Cal. and the boat laminated in S. Cal.

One of the worse cases of Blistering and core wetness was in a Kadey Krogen 42. It took almost 2 years to dry her foam core. Eventually the bottom was peeled about 1/4", then new layers of E glass and epoxy brought back that 1/4". The hull has been dry for over 10 years. I have seen boats which had no blistering--then 25 to 30 years old was sandblasted to remove bottom paint and the gel coat--when no epoxy coating-massive blistering.

This is why I always put an epoxy barrier coat on before painting the bottom, even if the boat is going to be mostly trailered. The Taiwan Built sailboat we took from Ca to Europe and back, had no blistering when we hauled out at about 4 years of age. We were in a yard with good compressed air and water. It only had pigmented laminating resin--no gel coat below the water, and no epoxy. We sanded the entire bottom, removing bottom paint, and then put on about 30 mils of epoxy. We lost track of the boat for over 30 years, but I did talk to the owner in about 2005, and no osmosis.

clayhubler · Posted: Fri Jan 01, 2021 1:33 am Post subject:

Dr. Bob, I'm going to sand the bottom of my boat and reapply bottom paint before it goes back on the trailer. Would an epoxy barrier coat be a good idea for the c-dory? I keep it on the trailer, but I do foresee the boat being in the water for up to a month at a time.
Thanks

thataway · Posted: Fri Jan 01, 2021 11:19 am Post subject:

A boat which already. has bottom paint is difficult to get rid of all of the paint. If the boat has not had bottom paint previously, then I would put the barrier coat of epoxy before the bottom paint.

Many use two colors of bottom paint, so that when the outer layer wears off, you know it is time to repaint. It also assures full coverage of the second coat.

clayhubler · Posted: Sat Jan 02, 2021 2:14 am Post subject:

Did some more cutting in the cockpit and did not yet find the end of the rot on the port side.

Also, got the rest of the foam out from under the v-berth and cut a circle for the 6 inch inspection hatch. There was a little standing water in the aft part of the compartment.

Then I set up the big heater to try to dry the core under the portapotti. I don't know if it will dry without drilling holes in it to let the moisture out, we'll see.

There was an area of sole under the galley that had really dark shavings when I drilled the holes, so I cut a small sample out to take a look. It is worse than I thought it would be and I can see a little delamination between the bottom skin and the balsa. I will need to cut out some more.

I'm starting to think that I may need to cut out the entire core...

Also, I used the moisture meter to check the forward deck coring and found one of my bow rail penetrations is leaking, but it isn't bad yet. I pulled the bow rail and all the other deck hardware up front so I could properly bed all the hardware. The factory didn't seal any of the core when they build the boat, and whoever put the windlass on didn't either. Luckily it doesn't appear to have leaked.

thataway · Posted: Sat Jan 02, 2021 1:15 pm Post subject:

Remember when you are next to metal that the moisture meter may read higher. I did some experiments quickly in. the house, and the amount was not great. I may try some larger metal objects to see what that meter will do.

The factory does not seal any part of the core. Unfortunately 90% of all boat builders do not seal the core. When I got my Cal 46, she was 18 years old, and for 10 years had been in charter service in the Caribbean. I pulled every deck penetration and sealed them. Fortunately no significant core issues.

When we were doing the studies on the hurricane damaged boats, we found some 30 year old sailboats which had been in Fl their entire life, and no issues with core. However, many sailboat builders, and larger yacht builders, put solid glass or solid wood or plywood, where they put high stress fittings, such as cleats or winches.

clayhubler · Posted: Mon Jan 04, 2021 2:06 am Post subject:

That is a good point about the metal, but in this case the reading is correct. The other bow rail penetrations were not leaking. This has also been confirmed when I overdrilled and reamed out the core. Here is a different flange:

clayhubler · Posted: Mon Jan 04, 2021 2:30 am Post subject:

I decided to remove all fittings and wiring that remained in the boat. I started with the rub rail; it had already started coming off in the back on the starboard side:

I also pulled the lazarette hatches. More bad news:

And where the downrigger pads and fuel fills were:

And also a flush mount rod holder:

The gunnel has me a little worried. I don't see how I will be able to get the rotten core out of there. Maybe I will get lucky and the rot will not go very far, and I will somehow be able to dry the remaining core. I am not going to put the flush mount rod holders back in, and I don't believe I will be able to make an acceptable patch over that hole with the non skid there. The best thing I can think of is to grind the nonskid off, and then maybe put a piece of aluminum diamond plate on the top of the gunnel there in its place. Might look kind of cool. Not sure.
Maybe replacing that core from underneath might not be as hard as I think. But then I still need to patch the nonskid...

Luckily the coring in the gunnel has a break at the bulkhead, and everything in front of the cabin is bone dry except that one bow rail penetration which was not really that bad.

clayhubler · Posted: Mon Jan 04, 2021 2:37 am Post subject:

On a positive note, the cabin sole does appear to be drying out. I do still need to enlarge the area I cut out in there, but I now think that I might be okay inside with just the area under the galley needing replaced.

Here are some pics of the meter and the original readings are written on the floor. I did some experimenting with the meter, and it doesn't seem to matter if the floor is hot or cold. In this case though, I hadn't run the heater for a few days. I wanted to give any moisture in there time to 'settle'.

Brewkid · Posted: Mon Jan 04, 2021 8:23 am Post subject:

Clay,

Check out this video on making your own non skid. https://youtu.be/UpsRljqBH0o

R/
John
Scallywag

san juanderer · Posted: Mon Jan 04, 2021 8:35 am Post subject:

ClayHubler, Sorry to see what you are experiencing. I have done the rebuild you are experiencing I think five times. In the end you will have personal satisfaction that the boat was rebuilt better than the factory. It is very sad that the factories have a out of sight - out of mind attitude. The chain locker fitting is so typical, I have seen it everytime ! The only saving grace is, most boats have these failures yet do not have a total failure. In one of your pics it is clearly seen that the kerf is open on the down side, this is typical as the binding fabric is on the topside. Once that water gets in there, it travels through those kerf channels. Even the high end boats have issues. In the end you will have satisfaction that you have sealed it all up better than the factory. Then enjoy your lovely boat.

clayhubler · Posted: Mon Jan 04, 2021 1:32 pm Post subject:

John, thanks for that video link. That looks like something I could do! I have watched many of Andy's videos in the past. Really good stuff.

San Juanderer, thanks for the kind words. Like you say, I am consoled by the fact that I would not be able to buy the boat I will have when I'm done for any price. It should be better than new, completely bulletproofed, and fully customized. Makes me want to repower it, too, but these Hondas only have 400 hours.

clayhubler · Posted: Mon Jan 04, 2021 4:41 pm Post subject:

Just cut out a little more in the port side in the cockpit. You can see that there was an area of coring that didn't really adhere to the bottom skin because it dips down a little. I think the balsa wasn't able to conform well enough. That's why I'm having so much trouble on the port side. The starboard side doesn't seem to have this 'channel' that the water was able to run. I have cut it back far enough that the wood is still very wet there, but it doesn't appear to be soft.

I'm going to drill a bunch of holes and try to dry this out. I may remove a bunch of the core from the around the holes and then pour in epoxy and then thickened epoxy and try to fill this void. I think it will end up better than it started, as the boat seems to have held up well structurally even with this void.

thataway · Posted: Mon Jan 04, 2021 11:33 pm Post subject:

You are continuing to go great work--what energy!!!

You will find all of the hatches--and the forward deck hatch while you are at it. Even the only new boat (255 Tom Cat) had wet core from just the wash down around the forward hatch. I pulled it--and found that half of the screws didn't go into the deck--the cut out was too large! I had to dry out the core, cut it back, seal it, and then add about 3/16" of glass all around the cutout!

All of the back hatches leak--there is a hatch which will fit the cutouts which is water tight--and that is what you will want to put back on. I don't have the number right at hand, but if someone doesn't, I'll look it up, and put a photo from my album.

For small areas of non skid, I have gel coated very thick, then used a Dremel tool to cut new non skid after laying out the pattern with pencil. Most areas you cannot see the difference. For larger areas, the areas as in the link are the way to go. You can roll or brush on the PVA, it does not have to be sprayed. That technique works particularly well if you are molding a new part. You can make a panel, and then cut out what you need also...

I would just cut back any obviously rotten core on the gunnel and then seal, fill and finish as you wish. A wooden plug for where the rod holders will work, put wax paper under with either a support, duct tape or even hot glue to hold until it has set up--then circles of mat and cloth to build to where you want to start the gel coat. There is no real structural strength there, so you don't need to feather in the edges on the 12/1 ratio. Another possibility is to put teak step plates over where the holes were. There are also framed rubber step plates which were used more in wooden boats, but would work to cover a defect where the rod holder was.

clayhubler · Posted: Sat Jan 09, 2021 6:30 am Post subject:

I am all done cutting! I did have to remove more from the transom, but I got all the soft core out, and now everything needs to dry.

And the mystery about the patch in the corner is solved. This boat took a hit sometime and was repaired, there was some foam coring in the very corner.

I also made this tool from 1/4 aluminum for removing core and it worked really well when used in the drill.

Cleaned out the lazarette hatch openings:

I also took some time to organize my photo album and there are more pictures there.

thataway · Posted: Sat Jan 09, 2021 11:44 am Post subject:

Outstanding documentation and a Job well done. It would appear that there was a very substantial hit in that transom corner. It would be unusual to have that happen in the water in the lower corner of the transom. Perhaps happened on the trailer, or when being transferred from one solid place to another (as in a storage rack)...