Delta RIB hull filling with water

[Paul Beaurain]

Hi

My 1991 Delta 6.5 RIB fills with water on a time basis. The longer it is in the more water enters. The Transom has 3 drain plugs and only the middle one is effected. (new o rings have been tried - nothing that simple)
Ie when the boat is lifted out the centre drain plug allows alot of water to come out. port and starboard drain plug OK.

The port side bung appears connected to the bow anchor locker. filling this it drains through and out (port bung)

Does anyone know the internal below deck layout for the compartments and how they are interconnected?
Any other ideas?
Thanks

[Ribochet]

Do you know if it is fresh water or salt water? - assuming it is moored in the sea - that might help narrow down the source of the leak.

What about the seal between the drain plug fitting itself and the transom?
Reseal it with Sikaflex to see if that makes any difference.

Are there elephant trunks fitted? - check them for any deterioration.

[Simon B]

Has it had any items secured to the floor? We had exactly the same thing with a badly sealed cylinder rack, the bow hatch on ours had a lip around it and sealed quite well with the cover over lapping this. Delta do have construction drawings but I never asked them for them so do not know if they give them out.

[Dry Run]

Hi Paul,

We lift ribs in and out of the water on a daily basis and we always take bungs out, elephant trunks down etc before they are put in the Dry Stack and you would be amazed at how many ribs appear not to be entirely watertight. Water gets in through all manner of ways including through deck and skin fittings (through dreck and through hull "A" fame bolts and wiring/steering fittings being the favourite).

Also you would expect that all non-watertight compartments would have some drainage into the bilges? But no that's not allways the case and even varies with the same manufacturer? In fact I only have 1 rib (out of over 100) that never has any water in the bilges.

If the water coming into your rib is salt water, then you obviously have a leak somewhere below the waterline. Unfotunately finding it can be difficult even with the boat out of the water. We've identified leaks before that let water in, but become watertight when you take the boat out???

I'm sure you'll check all the obvious possibilities first, but providing the leak isn't too serious and you have good bilge pumps and batteries, maybe it's something you could live with?

Hope you find the answer.

[Pete7]

Paul, I have only seen the deck out of one Delta which was about the same time yours was made. Under the deck was a series of light weight square ply box shapes dividing up the hull. Can't remember if they were connected.

Perhaps a call the Charles Dyas with the hull number.

I also think its a deck fitting. How about connecting an air line on the centre bung and wander around the deck listening for the escaping air. The alternative is to pressurise it with water.

We found that launching the club rib in the heat of the summer once in cold water the deck would hiss as air was drawn in via the bottle rack screws.

Pete

[gohelm]

paul, hi

I go with Pete on this one - i only saw the part underneath the console and there seem to be several compartments in the hull and this would also explain the triple drainplug setup. Since my boat (a Delta as well) originally was fitted with an inboard and waterjet i reckon the layout of compartments will be different than yours, so afraid cannot be of much help with that.

However, I have been looking in the original setup of my boat for a leakage problem with similar indicators as you mentioned, which turned out to be water ingress via the hinges of the engine bay. once inside, the water went over the air intakes all the way to the stern. It took a while before we found it, however the water ingress over the period of a couple of weeks was significant. With the inboard/engine bay gone there is no water remaining in the hull whatsoever...

I found (until now) very few badly attached items on the hull of our boat (a big compliment for how Delta's are built!) and only some 'aftermarket' items were badly done (top of the list was a 'repair' on on the console with silicon goo)

The way the console and the pods are attached are close to 'foolproof' and reckon this is not the cause, however if remember correctly your boat has the triple pod setup (1 driver pod + 2 behind) where there are rather large hatches on the front of the 2 pods in the back. They would be my first suspects for your problem.
Next to that all items which are glued to the boat after it left the yard (including fuelfilters, pumps, hatches, cupholders) are likely to be subject to 'lesser craftmanship' and care attaching it.. If it isnt the hatches, these would be 2nd on the list of suspects. The water ingress caused by them, if done badly, is significant.

good luck!

best regards,
Gabor

[Daibheid]

I found a particularly elusive leak in a friends RIB a few years ago by filling the deck with a few inches of water and then pumping some air in to the hull via the bung-hole. Some noisy bubbles revealed a deck/hull joint leak that was hidden under the tubes and would never have been found visually.
Worth a try?