CD25 Transom 2005 Model

[tpbrady]

I have the luxury of being able to store my boat inside this winter and decided to check all the hull penetrations on the outside. I removed the transducer and trim tabs and found some water infiltration. I drilled out the holes just slightly past the depth of the screw and found that there was void just behind the layers of glass and epoxy until you reach the core along the bottom of the transom. It goes all the way from port to starboard. I was able to run an 8 inch tie wrap all the way up to the end down the inside of the transom. I don't think it represents a problem with strength, as it just is a void left when the core in the hull was joined to the core in the transom. My concern is now I have a bunch of holes I need to fill with epoxy and a lot of space in the the transom for the epoxy to flow into.

My thought was to drill one more hole at the very bottom of the transom below the plug to be sure there isn't any residual water at the lowest point, be sure things are dry, and then use a closed cell polyurethane foam to spray in the holes to seal up as much of the void as possible. Once that is cured, I would rout that out around the holes, and then inject the expoxy where the screws would be mounted.

Dr Bob, your counsel please and thanks.

[journey on]

Whilst you're waiting for Bob to answer, here's a couple of links to pictures of the transome of Journey On, like yours a 2005 25.

First, this shows the layup of the hull balsa, and you can see the structural foam they use in the transome (the green stuff): Hull Layup

The outer and inner layers that turn the corner don't appear to be filled with a seperating core, as you noted.

Next, for what it's worth, heres a shot of the transome, with the same comment: Transome

Journey On has done very well with that construction.

As for repair, yea, dry, seal and use epoxy. Actually I just use 5200 to seal the screws. Epoxy seems a little brittle for me. As to drilling a drain hole, my comment is that as the boat sits on the trailer not all the water drains out since the transom rises up from the location of the bilge pump. My fear is that there is some water down around the tank. Our driveway is quite steep and when we come home, I let it sit there untill water stops coming out. But then, rain puts some back in.

Sorry about the links instead of the pictures, but posting pics didn't work this thyme. That isn't a generic hull, cause Laura, a daughter, took them for us.

Boris

[tpbrady]

Boris,

Actually, the reason for the hole is to drain the void area since it is wholly enclosed. I drilled it a few hours ago and the water is dripping out after I raised the tongue of the trailer. There isn't much but enough that you want it out. After the water stops dripping, I am going to put a heat lamp under the center of the hull to warm things up a few degrees to help drive the moisture out. After that the rebuild starts.

[thataway]

Tom,
I am not sure that you will be able to get foam to fill all of that void, since it is being placed in a level area, vs an area where the foam going down into a horizontal void will flow down and fill it.

The other issue is how fast the foam will go off, and expand, vs the type of foam. I don't think that the "great stuff" foam in a can will flow enough to fill this void. Injecting the two part foam may work--but again, the issue of expansion and area. You will have to probably mix several small batches and inject with syringes.

There are some other alternatives, such as a foaming epoxy, which can be mixed with a slow cure hardener, and use some thickening as microballoons, and inject in multiple places--or even use thin epoxy, thickened with microballoons, fill each area, then tape over the hole.


A thickened epoxy should fill and adhere adequately. On our 2003- 25, we had a very small void, but above that had wood, so we ground out any area which had any moisture, and filled it with glass and resin.

My concern with just 5200, is its ability to fully adhere. 90% of the time it adheres very well. But a very small percent it does not adhere to a surface; Thus I prefer to over fill with epoxy, and then put the screw into new epoxy and then use the 5200 just as a sealant--with the epoxy as the primary barrier to further water intrusion.

Here is a quote from the web site on instructions on using the pour in place foam:
The next thing you must be aware of is the blinding speed with which the foam starts reacting when the two components are mixed. You only have about 45 seconds to thoroughly mix & empty the pot. The mixing ratio is 1:1 & must be completely done within 20 seconds, that only leaves you 25 seconds to pour...

The expansion stage takes about 5 minutes, but the the cure to hard is around 15 minutes. It's best to allow at least 10 minutes before making the next pour. If the temperature is below 80° F, the expansion will be less than complete & the cure to hard will be longer. If you have to work in temperatures less than 75°, use a space heater. Ideal temp is above 80°...

When pouring the foam into a confined space, there must be enough space to contain the entire batch being poured & also enough opening for any excess material to expand out of. Over filling without ample relief openings can severely damage your project.


Most likely any of the methods will work in a satisfactory manor.

[tpbrady]

Bob,

Thanks for the input. It's such a small space, I don't think I am going to try to fill the whole thing up. I"ll shoot some waterproof foam on either side of the holes to form a pocket for the epoxy "plug" formed with West System Six10. The rear of the epoxy plug will extend into the wood core. I'll drill it out and then seal the screws with 4200.

[thataway]

Tom,
That should work fine for you. You apparently have a wood transom and Boris has a foam core transom--so some time in the year, the core material was changed. It would be interesting to know if the laminate schedule was changed, since I found that on my boat (2003) it was a bit light on the splash well, which was susposed to take some of the thrust of the engine.