Catamaran filling with water!

[piratesbooty]

Hi all,

I have a 1976 31' Prout sailing cat. I am a liveaboard. I have finally found the source of my "leak" in my upper deck (where the settee is, as opposed to the lower pontoon walkways). I came home to a familiar but much worse sight two days ago. 3-4 inches of standing water in this upper deck area. For once, this happened when it was not raining and I was able to determine that I was not leaking as much as filling up with water, as the wave action was quite intense that day. The area filled during the 3 hours I was off the boat.

So I ripped up the carpet and the board underneath and I found 2 2.5 inch diameter holes cut through the glass (possibly for a previous table mounting?) and the whole area below filled with water. I wet dry/vac'd I don't even know how many gallons (3-4 garbage cans worth). I temporarily plugged the holes with rubber roof vent seals that can be stuffed in and create some suction.

I am planning on hauling the boat in the spring to do the yearly scraping/painting and now to fix this problem. So, two questions:

1. What is this area called?? It is the "V" that sits (usually) above the water, while the pontoons are in the water all the time. The keel??

2. How is it possible that this area is filling with water? The boat was surveyed last April and the hull was intact (or so I was told).

and 3. Any other solutions until it can get fixed permanently?

We wet/dry vac'd all the water out of that V area but I have no doubt it will fill back up this winter, as the waves pick up again. Any thoughts would be greatly appreciated.

[bacampbe]

That's interesting. If the area (I assume you are talking about the bridge deck (between the hulls on a catamaran, as opposed to aft of the the companion way of a mono), but I don't know the layout of the Prout).

You say that area is normally above the water. If wave action was entering through a breach, I'd sort of expect the water to run back out. Unless it's splashing over something and getting trapped. Or coming in from above, and getting trapped. I gather your hulls (pontoons) are dry?

Assuming you are in salt water, have you confirmed the water is salt? (as opposed to stored fresh water, rain water, etc).

Do you have anything running that pumps water on board? (i.e. engine, generator, a/c, heat pump, water-cooled fridge?). Could it be leaking? Any through hull fixtures on the bridge deck? Do you have a single engine on the bridge deck or twin engines in the hulls?

Can you inspect the underside of the bridge deck while the boat is in the water?

If the problem persists and you can't find the source, I'd personally be concerned about waiting until spring to haul it.

[piratesbooty]

The answers to all your questions are all pretty much "No's". Pontoons are dry. One outboard in the back. All other areas of boat are dry. No leaking coming from anything. It was salt water. It was very clear that the "V" area was filling up with water in these heavy waves (area remained dry while it is calm), then leaking into bridge deck. Also the bridge deck only fills about 3-4 inches up--as in, it wasn't like the boat was about to sink with a continual flow coming up through the holes. It stayed steady. No thru hulls in this area that i know of and water was compartmentalized to this area. No bilge in this area, but 4 in the pontoons.

It would be fairly difficult to get underneath there to look without pulling her.