I've heard of the LVM pumps and will look into them, though I would prefer a good manual pump as I'm not always going to have a power supply to hand. My dual action hand pump supposedly pumps 300 litres per minute but you'd have to be going some to keep that up for all three compartments and the floor
I've seen a large foot pump with a small plastic lever which has three settings, presumably to adjust volume versus pressure. Just need to know whether it's going to be any better than what I've got already.
The more I think about this, the more I think I need to get a smaller dinghy.