JEM Watercraft

what are their purposes? do we need them? pros/cons?? i don't quite see why or how they are used.

They are what allow a SOT kayak (or other boat) to be self-draining. They are used in conjunction with a subfloor.

draining for if water gets inside, you can get it out through them? or for while it's in the water? i understand that they have to higher than the waterline, right? but then, if water does get in, it will have that much water sloshing around in there. or is that the intended goal?

The top of the scuppers... the same height of the subfloor... is/are designed to be above a certain waterline.

Let's say your boat displace 400 pounds at a 4" waterline and that the top of your scupper height(s) is also 4".

Long as you don't have a total displacement of 400 pounds or more, the water will generally stay out of the cockpit area. If you did get some water in from a wave, the water would drain out the scuppers.

i must be missing something then. if the scupper was, say, 2" tall. wouldn't you have the possibility of having 2" of water in the boat before it could go over the scupper and drain? even more if the hull was a vee hull and the scuppers were high toward the chine? please forgive my ignorance here, i'm trying to wrap my mind around how these work. i'm missing something, i just can't seem to figure out what. maybe this is why kayakers carry a siphon pump? to suck out the water below the scuppers? i'm a mechanical engineer, and this should be basic for me to understand, but embarassingly enough, it goes over my head for some reason. this is going to be one of those "smack my forehead" moments when i get it, i'm sure.

Scuppers are only in Sit on Top kayaks.
The scupper would sit between the hull and the cockpit like this picture. Thats really the tank well and not the cockpit.

Another look from the cockpit.


Water that would get in the cockpit would drain out thru the scupper.

DM

The top of the scuppers are above the waterline (as long as the boat is not overloaded) yet at a low point in the cockpit. Therefore, water is drained out via gravity. If you look at the drawings and photos of the Sabalo SOT Kayak in the products menu, you can visualize how they work.

AHHHH!! thank you for the pics. that clears it up for me. i thought the blocks i kept seeing were all that was the scupper, i didn't realize the top of the blocks would end up being under or flush with a cockpit (or well). i thought it was just a block with a hole throught it.. i see now how they work. thank you guys! much appreciated!