water seeping out of bottom transom - OK?

kdupreez · 16 November 2015, 04:48

I recently bought a used Zodiac Pro 470 (1991 year model)

its in fairly good shape and i was drilling small holes in the bottom of transom to install transducers and water started running out of the holes..

is that bad?

picture below of hole and water seeping out..

beerbelly · 16 November 2015, 05:44

do they have plywood inside the transom ? if so you might have problems if the plywood is soaking wet inside

kdupreez · 16 November 2015, 06:25

no idea if they do..

This is a fiberglass hulled 1991 Zodiac Hurricane Pro 470 RIB.

Does anyone know if it has wood down that low?

Sonar · 16 November 2015, 07:11

looks to me the holes you have drilled are below the level of the drain plug
Hence there may well be some water left in the hull..

gtflash · 16 November 2015, 07:18

What came out of the hole when you drilled it? Fibreglass? Wood? Quite often the lowest part of transom is solid glass. If you are not sure another hole will tell. As sonar says if you went right through it could just be bilge water

kdupreez · 16 November 2015, 07:41

I'll drill a little higher and check.

The smaller hole was about level with the bottom of the drain and another slightly above.

the drain in the pic is not a hull drain plug, its a hole through the transom that drains from the deck's lowest point int the back of the boat.

I'll drill a little bigger hole higher to check for rot.. i can plug it later with 5200 or something..

Phil M · 16 November 2015, 11:22

I have 1980's 530 Pro. The transom has an upper angled section, which solid ply (and thankfully is solid) and a lower vertical fiberglass only section which the hull void plug goes through. This section has no ply behind it and is purely fiberglass about 5-6mm thick. The area where the deck drain plug goes through is solid ply. I had the reverse problem when I forgot to fill the old transducer holes into the fiberglass section and filled the hull somewhat.

Chris · 16 November 2015, 14:14

Did you drill all the way through the transom, if you did (stick something through to check) then I am sure you will be fine as this will be water in the bottom of the hull, below the drain plug.

jyasaki · 16 November 2015, 15:08

Could drill the next larger size and see what comes out in the bit flutes (If it's composite, you should be OK. If it's wood, you may have a rot problem, now or later.)

In any case, it would be wise to seal the hole with a bit of marine caulk or 3M 4200 prior to reinstalling the transducer (squirt/tamp some sealant in, then insert screw.) Especially if the boat is exposed to hard freezing temps, as any residual water will try to split things when it freezes.

jky

office888 · 16 November 2015, 23:17

It has a wood core.

Your transom is probably shot. Smack it with a hammer in a couple spots. Good wood rebounds. Bad wood makes a thud and cracks the gel coat.

cgoing · 17 November 2015, 01:39

The appears to be the deck drain if I am looking at it correct? If so there should be a lower hull drain plug that can be removed and will drain the hull cavity. Can you post a photo that shows a larger area of the transom?

kdupreez · 17 November 2015, 04:43

Quote:

Originally Posted by cgoing

The appears to be the deck drain if I am looking at it correct? If so there should be a lower hull drain plug that can be removed and will drain the hull cavity. Can you post a photo that shows a larger area of the transom?

So this ended up being the lower hull cavity.

this specific transom has a left and right cavity thats somehow split and isolated and it has 2 drain plugs, one each side underneath the left and right tubes on the transom..

I blew compressed air into the drilled holes and i could feel all the compressed air escape through the drain plugs.. poured water into the drain plugs and it ran out of the drilled holes.. so seems OK and by design..

also drilled a larger hole further up, closer to the engine and hit solid balsa.. phew!!

bizarre hull / transom design..

jyasaki · 18 November 2015, 15:21

Could be 2 things happening:

Hopefully, the drilled hole, and the drain holes, go through the transom into the bilge. Blowing air into one hole ends up in the bilge, and comes back out the other hole.

Worst case, the wood (if there was wood) in the transom is gone, and the two holes are connected because there's not enough material left to support two holes, and the air blown in is making a U-turn inside the transom itself.

One question I've got (curiosity more than anything): Is the bilge cavity actually compartmentalised? Or did they drop a drain on either side of a raised keel structure to make sure you could drain stuff? Your air test would tell that by blowing air into one drain hole and seeing if it escapes the other one.

jky

cgoing · 18 November 2015, 16:47

The base of that transom does not have wood in it from what I recall when i removed the deck on mine. The wood in the transom started at about level with the deck.

kdupreez · 19 November 2015, 06:16

Quote:

Originally Posted by jyasaki

One question I've got (curiosity more than anything): Is the bilge cavity actually compartmentalised? Or did they drop a drain on either side of a raised keel structure to make sure you could drain stuff? Your air test would tell that by blowing air into one drain hole and seeing if it escapes the other one.

Yes, bilge cavity is compartmentalized, blowing air into one side does not let it come out the other.