One way Drain valve at back of boat?

[Rappey]

are many small motorboats self draining?

The majority are not self draining.. Ones that fit an elephants trunk draining system that live out on moorings tend to sink...
I have a ryds 4.85 and it is self draining. The deck is completely sealed from the void in the hull and has a drain hole either side at the rear..
There is an external drain plug at the bottom of the V hull.
It is rare to have a small boat that has a self draining interior when its afloat.

 

[eve1]

I hear people joking about sinking boats but do moored up boats that are left really sink sometimes?
I never heard of this Ryds make, but I googled some photos and the boats look nice, which country are these made in?

About my boat, If there was someway I could put 4or 5cm of foam everywhere on the deck, then a false floor above it, then a small hole above that would drain out by gravity.
Has this sort of thing ever been done as a modification. It would make it self bailing

 

[Rappey]

I hear people joking about sinking boats but do moored up boats that are left really sink sometimes?

Certainly! Open ones are left to fill with rain. It reaches the transom and in comes the sea.
They usually flip over with an air pocket in the upturned bow stopping it from completely sinking while the weight of the outboard holds the stern down.
Awkward to recover.
Yachts and motorboats sink in marinas. Usually skin fitting/hose failure.

Other boats leak. Once the bilge pump battery goes flat the boat starts sinking.

 

[Rappey]

About my boat, If there was someway I could put 4or 5cm of foam everywhere on the deck, then a false floor above it, then a small hole above that would drain out by gravity.
Has this sort of thing ever been done as a modification. It would make it self bailing

Perfectly feasible. My drains are on the sides of the hull at the rear of the cockpit floor.
If I stand in that corner sea comes in a little as the holes are only about 1" above the sea .
Both have plugs to close them.
The new deck really does need to be 100% watertight .If not the hull will also fill up.

 

[girlofwight]

I bought a 3.3m rib tender earlier this year which had a flapper valve or similar . If there was too much weight at stern, eg during engine maintenance or sitting on rear bench seat when not underway, it back filled.

I soon became fed up with this and had sparky put a sump pump in.