Advise needed for self draining deck

[teamplonker]

Hello everyone

Back again for some advise on self draining deck.
After finally deciding on a 40hp two stroke outboard for my still unnamed and unidentified rib, I took it for a test run in Aug down at teignmouth where it performed very well.
My only suprise was the deck did not drain when I removed the bung from the transom as we were motoring along.
I am wondering if the bung is in the wrong position on the transom,does any one have any idea's why it did not drain.

Thanks in advance
Lee

[PeterM]

Is hard for me to see on the pics, but is there a one way valve type bit of rubber in the hole, that could be installed backwards?....

[teamplonker]

No its just a plastic strainer.

[PeterM]

Originally Posted by teamplonker

No its just a plastic strainer.

In that case - maybe the boat needed to be going quicker to drop the water level on the outside of the transom ?

I've similar on one of my boats - I need to be doing about 10knts for it to work, and thats with just a clear hole and no plastic in the way .

[teamplonker]

When i pulled the plug I was doing about 30 mph and it did not draw the water out and as I slowed it let a hell of a lot in. At first I thought the strainer was blocked but it was'nt. I am thinking of either putting in a new larger bung or may be fitting a hand pump.
Another idea was to put the drain lower down in the bilge and cut hole in the back of the deck so it will drain both bilge and deck as I do not know if there is any water below the deck .

[Locozodiac]

If the plastic strainer has a small middle hole, you are missing the central round diaphragm. It's a one way thin diaphragm with central pin. If that's the case, buy a standard Zodiac type, should work well.

Once inserted on backward valve, central pin must be facing bow. Is there a round plug covering outside water valve ? Buy one if it's missing too.

Happy Boating

[Ribstore]

Looks like the diaphragm is missing...see here and here for examples.

[teamplonker]

That looks like it ,I guess the diaphragm is missing in mine.
That would explain the water coming back in but why did the water not drain away when i was under way.

[PeterM]

Originally Posted by teamplonker

That looks like it ,I guess the diaphragm is missing in mine.
That would explain the water coming back in but why did the water not drain away when i was under way.

Could just be the holes (through the strainer) are so small they slow the water so much its hardly noticable that it is infact going out ?

Its not under 'pressure' as such ...have you tried the trailer test - put some water on while its sat on the trailer and see how quick or slow it comes out ?...the slowness may surprise you.

[teamplonker]

Thanks for all the advise I will try it while its on the trailer tomorrow .

[teamplonker]

In the later of the two examples is that two parts that join together in the transom

[teamplonker]

Originally Posted by Ribstore

Looks like the diaphragm is missing...see here and here for examples.

In the later of the two examples is that two parts that join together in the transom

[Peter_C]

FWIW I have a Zodiac and when I replaced the diaphragm, of which you are missing, it had a larger stem which required I drill the hole out ever so slightly.

I put a 3" elephant trunk in to drain the deck and have nothing but good things to say about it. We drag a fair amount of water into the boat with our drysuits (Pockets mostly) and scuba gear, and it is nice to be able to drain gallons of water quickly. I also have a bilge pump to drain below the deck but that is mostly to lose weight for beach recovery.

If it were me I would like to know what is below that plug between the hull decks. If it is foam filled, then a drain isn't needed, but if not...maybe it should be foam filled, or at least have the capability to be drained.

[Locozodiac]

My rib exits water through diaphragm very poorly if rib is moving at plane, if throttling down to maintain bow rise while moving forward water exits much faster.

If water valve is in general good condition, just replace the middle diaphragm, if the stem fits thight in small middle hole much better, before inserting apply some grease to slide while pulling it from inside of rib. If stem has side play eventually will lose it while water flow exits diaphragm. The thinner the diaphragm, will seal the better.

Happy Boating

[teamplonker]

Originally Posted by Peter_C

FWIW I have a Zodiac and when I replaced the diaphragm, of which you are missing, it had a larger stem which required I drill the hole out ever so slightly.

I put a 3" elephant trunk in to drain the deck and have nothing but good things to say about it. We drag a fair amount of water into the boat with our drysuits (Pockets mostly) and scuba gear, and it is nice to be able to drain gallons of water quickly. I also have a bilge pump to drain below the deck but that is mostly to lose weight for beach recovery.

If it were me I would like to know what is below that plug between the hull decks. If it is foam filled, then a drain isn't needed, but if not...maybe it should be foam filled, or at least have the capaIbility to be drained.

I would also like to no know what is in the void between the hull and deck ,I think its time to get drilling.
Also what is snap elephant trunk.

[teamplonker]

Originally Posted by Locozodiac

My rib exits water through diaphragm very poorly if rib is moving at plane, if throttling down to maintain bow rise while moving forward water exits much faster.

If water valve is in general good condition, just replace the middle diaphragm, if the stem fits thight in small middle hole much better, before inserting apply some grease to slide while pulling it from inside of rib. If stem has side play eventually will lose it while water flow exits diaphragm. The thinner the diaphragm, will seal the better.

Happy Boating

I think I would like to fit a larger drain as no matter what speed i was going it seemed as though it was just not draining at all.

[nik]

These worked well on my boat, less messy than elephant trunks.

[Jizm]

Originally Posted by nik

These worked well on my boat, less messy than elephant trunks.

Just fitted those on mine but yet to see if they are ok. Saying that they've been fine on other boats I've seen them on.

[Peter_C]

Those scuppers above have been known to sink many a boat, if they are not well above the water level. In fact there was a post on here recently of someones, RIB putting the engine underwater from scupper failure. An elephant trunk is not very expensive, and much less likely to fail.

[Peter_C]

This is relevant to this thread. Inflatables are pretty much unsinkable, but still sinkable enough to cause damage.
How to Prevent Your Boat from Sinking: Boats and Yachts Maintenance and Troubleshooting :