I used to use a small 5 quid ebay oil syphon to pump out water from the sib.
After the third one broke last year I decided to buy something a bit more robust.
Most Sibs are wet boats - particularly if you try to make headway against a chop.
My Honwave gathers water from rain, spray and breaking waves and stores it beneath the floor sections.
There it runs back and lies at the transom.
Trouble is once there is a sizeable amount of water under the floor it squirts up like a whale spray through a blow hole which is the drain plug cut out.
This seem to happen when you plough through sum rough waves. This is caused by the floor to compressing and forcing the water up through the drain plug cut out.
It really does my head in getting salty water sprayed up into my face.
I like the pump fixed to the transom as you would need 2 hands to position / hold the pump and pump the water away otherwise.
I can set course at sub planing speeds tighten the tiller steering then use my free tiller hand (left) to pump the water out.
Going at sub planing speed makes the bow rise and causes the water under the floor to run back to the transom where the pump can suck it out.