It is confusing. In your example, the water will go away through the drain
holes until the water inside the cockpit is at the same level as the water
outside.
I have just such a hole in my boat's cockpit. I installed a 1-1/2-inch
drain hole in the transom that is just below the waterline. I have a
transparent hose connecting the transom fitting with a fitting in the
cockpit floor, which is just above the waterline. The transparent hose
crosses the inside of the lazarette so I can see the water in the hose. It
is always at the same level as the water outside the boat.
I once had three men in the cockpit so that the stern was lower in the
water and the cockpit floor was then slightly below the outside water
level. Some water then flowed into the cockpit from the drain hole so I had
to put the stopper in.
Harry
P14 #234, Manatee
Mountain View, CA
>Thanks a lot Harry!
>
>I have been very confused when I have been thinking these "flotation &
>drain holes"-things. They are quite simple but anyway it is easy to get
>confused.
>
>Am I right if I say it this way:
>"Let's assume that I have boat. In the boat's cockpit there are big
>drain holes. Let's also assume that cockpit floor is above waterline
>(when there is no water in cockpit). We can also assume that cabin is
>closed so we can examine only cockpit. Ok, here comes my question: What
>happens if cockpit gets full of water? Let's assume also that there is
>flotation materia in cockpit so boat will float about 5 inches high even
>when cockpit is full of water.
>
>I hope you get the idea!
>
>So what happens? Do water go away though drain holes or what happens?
>
>Please help me folks, I am confused ;-)!
>
>Regards,
>Oskari
>
>> The drain holes will still work underwater if there is enough flotation in
>> the boat. Imagine a wooden bucket with a hole in the bottom. If you
>> submerge the bucket so that it is full of water, then release it, but don't
>> let it tip over, it will rise up and water will escape through the hole in
>> the bottom until the bucket reaches equilibrium (the point at which the
>> bucket displaces its own weight of water).
>>
>> Harry