How long would it take to fill up with rainwater?

James W

James W

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Evening all.

I've just bought a nice little Hurley 20 that had been left on it's mooring for a while (how long I don't know). What I do know it that it was full of water: the bilges were completely full, the cushions were like sodden wet sponges and the every possible locker had water in it. The boat was so full that it listed a bit on it's mooring and the yard even noticed that the extra weight she was carrying when she was lifted out.

The water is freshwater and I know we've had a huge amount of rain in the last six months, but how long do you think it would take to get this full?
 
If we are talking about an open boat - not that long. But yours is not open. I can't remember but I assume that the cockpit is not self draining? So think of the snow and rain we have had. Christmas had a lot of flooding on the roads in the Essex area so quite a volume has fallen. Cushions 'sodden' doesn't sound great. Deck or window leaks? I would suspect windows first assuming the deck is a one piece moulding which means it can only leak at the deck/hull joint or around fittings.
 
Could be days, weeks, or months depending on the scale of the deck leak.
If it is 1 drip per second, if the drip is just 1ml, that is nearly a gallon per hour.
 
tillergirl said:
If we are talking about an open boat - not that long. But yours is not open. I can't remember but I assume that the cockpit is not self draining? So think of the snow and rain we have had. Christmas had a lot of flooding on the roads in the Essex area so quite a volume has fallen. Cushions 'sodden' doesn't sound great. Deck or window leaks? I would suspect windows first assuming the deck is a one piece moulding which means it can only leak at the deck/hull joint or around fittings.
Click to expand...

Thanks Tiller Girl.

For all the water, she may as well have been an open boat.

I'm thinking windows, but the usual tell tales aren't there (water stains etc). The washboards are perspex and fit well enough and I know the cockpit doesn't leak as the drains weren't open and it was full of water too! The locker lids are pretty rotten but even if they leaked that wouldn't explain the soaked cushions. It's time to start looking seriously at holes I think.
 
ridgy said:
Could be days, weeks, or months depending on the scale of the deck leak.
If it is 1 drip per second, if the drip is just 1ml, that is nearly a gallon per hour.
Click to expand...

Good point, i've never thought of it like that. A gallon an hour is a huge amount in a small boat.
 
James W said:
Thanks Tiller Girl.

For all the water, she may as well have been an open boat.

I'm thinking windows, but the usual tell tales aren't there (water stains etc). The washboards are perspex and fit well enough and I know the cockpit doesn't leak as the drains weren't open and it was full of water too! The locker lids are pretty rotten but even if they leaked that wouldn't explain the soaked cushions. It's time to start looking seriously at holes I think.
Click to expand...

I have seen boats around here where the cockpit drains get clogged up. The cockpit fills with water which then runs over the bridge deck into the cabin. Usually this water gets past the washboards easily. My guess is that this is what caused the flooding. (unless the bridge deck is very high). How long. My guess is that 1 inch of rain will due to run off from cabin and side decks give 2 inches in the cockpit. So guess 6 inches of rain to fill cockpit then perhaps 2 inches of rain per inch of water in cabin/bilge. Depending on area of bilge/floor. But that is all very variable.
I can't imagine that much water inside from window or deck leaks alone.
I do suggest you dry it out ASAP and check for wood rot in internal fittings. good luck olewill
 
It may not be that long. First thing to do is dry her out completely and see how quickly rainwater now re-enters your boat and its means of ingress. Old cushions often need replacement so that in itself is not a big deal. Is she pointing into or away from prevailing wind and rain? Sometimes the washboards can let in quite an amount. Check your bilges regularly for the first while and become a leak detective!
 
James W said:
Thanks Tiller Girl.

For all the water, she may as well have been an open boat.

I'm thinking windows, but the usual tell tales aren't there (water stains etc). The washboards are perspex and fit well enough and I know the cockpit doesn't leak as the drains weren't open and it was full of water too! The locker lids are pretty rotten but even if they leaked that wouldn't explain the soaked cushions. It's time to start looking seriously at holes I think.
Click to expand...

That is interesting. Why were the cockpit drains closed? Perhaps the hose from cockpit to seacock is perished and the seacock was closed resulting in some seepage through the hose or the the hose/cockpit sole join? Just a possibility for you to check.
 
Definitely suspect windows. The water may drain down behind lining trims if fitted. Any boat of that age is likely to have perished window seals. Otherwise just get someone to run a hose all over the deck/coach house and watch from the inside with a torch. Possibly spread talc about to capture the water stream.
 
If one drip is just a ml?
If one drip were a ml, you'd be concussed every time it rained. 0.1ml, at most.

To the question:
Burnham on Crouch has had 92mm of rain this year. Average annual rainfall is around 500mm. The last 12 months have been wetter than average by an amount I can't find numerically, but at most +50% = 750mm.

How long would that take to sink the boat if every drop of that found its way below?
You'd need to calculate the area of the decks versus the effect below, which is easiest done empirically. (The alternative is lots of measurement and calculus I've long since forgotten.) So -- sorry James W -- we're going to dry the boat then fill it via a water meter until it sinks.

Or guess. How many tonnes of water would it take to sink her? Well, her displacement is around 1 tonne, I think (?). As she settles lower in the water the volume per cm of sink increases (because the hull footprint is greater higher up). So let's say an extra two tonnes would send her to the fishes. L X B is 6 x 2m, so area is, say, 9sq.m. (it's probably less). 500ml of rain over 9sq.m = 4.5 tonnes. 750ml of rain over 9 sq.m = 6.75 tonnes. So she'd sink in about six months with average rainfall, four months with last year's deluge. But there are lots of guesses in there (and it's early so I'm not at my best). And besides, in reality by no means every drop will be finding its way below.

William H's point about back-filling is well-made, particularly in yachts who's deck and cockpit drains share a common skin fitting. A yacht, a Nicholson, I think, sank at her pontoon here in Levkas in precisely that way a few years ago. As soon as I heard about it I filled in the deck drains on my Rival 32 and cut scuppers in each gunwhale.

Good luck drying her out. Sounds an awful mess.
 
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Many thanks to all who have replied, you've been really helpful as ever.

I've attached some pictures of the cabin before and after the bail out and i'm hoping that she'll dry out without too many problems. The cushions are in a sorry state but i'll try and dry and them out before deciding whether or not to bin them.

As to the cause, i'm pretty sure that the cockpit drains (they were blocked as well as closed) might have had a lot to do with it. I'd emptied out the cockpit by hand three weeks previous, but when she was lifted into the yard the cockpit was full again and I think there's every chance that back filling could have occurred. The yard crane showed her to be a tonne over weight, so that's a tonne of water, as well as the many buckets that had already been taken out on her mooring before she came in. That's a lot of water and, as macd said, it probably wouldn't have been long been she'd have been sent to the fishes!

The cockpit drain pipes though seem to have been replaced quiet recently and are in very good condition so that's not the cause. Maybe a washboard had been left at some time? Anyway, plenty to think about.....and clean up. Thanks everyone!
 
My motorsailer was delivered to Milford Haven and chocked up ashore last April while we were in Greece. We first saw her there in August, when the deep bilge was seen to be full of water. On pumping out we measured 20 gallons, which all seemed to have leaked through windows, doors, holes in the deck, etc., which we have spent most of our time since trying to fix.

We have twice partly flooded a boat due to cockpit drains blocked by leaves - a speciality of Port Dinorwic.
 
You probably have a number of small areas to look at.

The worst I had was a tiny self tapping screw at the lowest point of the deck. A vast amount of water came through it, as it was draining a large area of deck directly into the accommodation.
 
That amount of water is not surprising. My Foxcub 18 leaked up to the cabin sole within about a month if I didn't pump her out. It was entirely window leaking.
 
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