It is difficult to create a satisfactory bilge pumping system for an Atalanta. I don’t think many actually have a working bilge pump.
Mikes solution is probably as good as you can get. However it is possible to mount a bilge pump in the cockpit and route permanent pipework to two compartments using 2 way valves (you can buy them from the usual places). Calista has such a system. In her case that covers everything except the aft cabin and the focsl. Not perfect but I prefer something built in rather than movable.
You shouldn’t necessarily dismiss an electric system. As long as the batteries are not in the bilges, that is a perfectly reasonable arrangement. You are more likely to be able to service every compartment that way. Manual bilge pumping is hard work – and you might also have other things to think about in an emergency.
If a leak is that bad – you arn’t going to be able to keep it afloat anyway.