Achilles Heal Found ( transom ice box/ hatch )

[abl1111]

I had recently posted about my 1975 23' Tsunami having water in an area that I could not fathom how it got there " stringer weep hole leaking water ".

A lot of discussion w/ some good ideas. Thx. But today I found the reason and it is definitely a design issue ( and a sure reason for a lot of failed transoms over time )

It's the garboard tube drains that drain the (2) transom mounted ice boxes. A hull, no matter what, flexes - new, old it does not matter it just does. And the top cap of a boat, if not glassed in place, a rarity - will flex a bit on the actual hull.

So, where these ice boxes drain out, through a garboard tube, out through the transom - there is a hell of a lot of flex going on - even if it is a small amount. Those tubes are under a lot of force. They are not built to withstand it so they move a little.

Just $ years ago I did a transom - plus a lot more, and I replaced those garboard tubes, sealed the new, exposed transom in that area w/ epoxy ( around the hole) and used Life Caulk to seal the garboard tube in place.

Note: The transom rot from those tubes failing the first time was quite severe.

Anyway - this is where my mystery water is coming from. The sealant failed around the garboard tube and without me knowing, rainwater or washdown water was filling the ice box, and leaked around the garboard tube - down the inside of the transom ( as opposed to through the garboard tube and out, where it's supposed to drain ) and was pooling on the outside side of the stringer.

This has answered a few questions for me and created an area that I want to repair:

1) repair the garboard w/ sealant ( for now ).

2) figure out a better mousetrap to avoid the effects of hull flex ( without having to run the drain through the side )

3) repair the weep hole through the stringer, so if water does pool in this area again - it will go through the actual hole for that purpose and not around it, through the foam and out that way - thus wetting the foam.

Just one of the many issues we have to deal with when keeping classic boats alive for another 30 years !

Hope this helps someone out.

[strick]

Thats a good find thanks for posting it.

strick

[JW-Tex]

Would the solution be to use a drain fitting with a hose barb fitting and route the hose into your scupper or its own barbed transom fitting so the flex is absorbed by the hose? Is there enough room to do this?

Would this same problem occur where long brass/pvc scupper tubes are being used running from the deck cap through the transom?

[oldfielder]

I don't know why I didn't think of it when you originally posted, but I had the exact same problem on my cc last year. It drove me crazy because I spent so much time thinking about where the water could be coming from in the front of the boat. One day I was on the boat in some rain, took a look in there by chance, and saw the water sheeting down the inside of the transom. That little molded in depression under the tube doesn't help when you lose the seal because the water gathers under the lip of the tube and wicks right down the outside of the tube to the transom.
I'm not ambitious enough to do anything other than seal it up good and keep an eye on it.
Speaking of flex, this was the same time I decided to take a closer look at the forward fish box drain tube, which also takes a lot because it goes between the liner and the hull. Sure enough, the old tube had a decent crack in it. That one came out and in wnet a threaded thru hull. Everyone on the board who has an older boat should make it their work to check that forward tube carefully-seems like it could definitely be a boat killer if your boat was heavy enough.

[Capt Chuck]

Would the solution be to use a drain fitting with a hose barb fitting and route the hose into your scupper or its own barbed transom fitting so the flex is absorbed by the hose? Is there enough room to do this?

Good idea Chris. My transom also was rotted by these plastic drains. When I enclosed the transom I filled these in. I then drilled new drains thru the bottom or the lowest point of the boxes. I routed flex tubing and "T" them into the livewell drain tube which flows out the side.

I think everyone who has the original set up should check the integrety of these drains

New drain thru the center


Barbed drain to flex hose "T" to the livewell drain

[nestorpr]

That's probably one of the reasons my boat's previous owner eliminated ALL the transom thruhulls except for the bilge drain, he drained everything into the bilge and depended on the 2 LARGE bilge pumps to drain it out. I understand this is not the best solution but he thought that with these boats, the fewer holes you have thru the transom, the longer it will last.

Something else that may help is to make a larger hole thru the transom, fiberglass it thru and thru, and then install the fitting and seal it with epoxy or silicone (same as when you make a hole thru composite materials, you never leave it exposed to possible water intrusion). That way, even if the seal fails, it won't seep into the transom ruining it. I've seen it on older Bertrams and other high-end boats and apparently it works for many years, those older transoms were still dry as a bone 30 and 40 years later. Just a thought.

[abl1111]

The more I think about it, this same problem exists w/ the floor scuppers - a lot of flex breaks the seal of the garboard tube between the floor and the bottom of the hull.

That's why a lot of those wood blocks are soaked or rotted making the problem even worse.

The ice box problem is a definite transom killer. And the fix of going through to the bilge - as someone mentioned; the idea of draining into the bilge, I think, is a bad one.

The only idea I do like is capping the exisiting holes (in the ice box and uugghh, the transom ! ) and running through the bottom of the ice box and out through the sides of the boat.

If I could install something w/ the existing set-up that is 'bullet-proof', I would do that. would epoxying a PVC tube through do it.

Either way, it's a bitchy spot to work in , so I would recommend if you're doing a transom, think this part out, as well as the through-the-floor-scuppers, now to avoid the hassle later.

Both of these areas, in original design, are very suspect for failure...