The other thing to keep in mind is that if it's rough enough to make you capsize and use your bilge pump,it will be rough enough to have water sloshing into your cockpit while you try to manually pump it out without your spray deck on.We do regular training days on rescues and generally after the 2nd one ,people fit an electric bilge pump,total weight would be less than a kilo,fit it either behind your set and put the waterproof battery box in the back compartment ,or at the front of the cockpit if you have a pod seat or not enough room at the back and put the battery box in the front compartment attached to the bulkhead.Put a magnetic reed switch and magnet on the deck near the cockpit and ensure everything is sealed and soldered ,and you will get years of trouble free use .I use a 1.2 amphour battery and I will get 30 full cockpit pumpouts of it ,just regularly recharge it and use a low amperage charger or you'll destroy the battery.