Can anyone tell me the performance of a 5 or 6 HP, which I could keep stored up front until I need it and move it around, say to a dingy. Right now I have a Honda 90, Honda 9.9 (100+ lbs) and an 80 lb thrust electric on the stern, and another 80 lb thrust electric on the bow. Actually the stern electric is bolted to the antiventilation plate, which some folks call a cavitation plate, so all stern units are on the transom. The electric weighs about 12 lbs, so no big deal for the electric. The batteries and controller are under the seats in the cabin. That is where the real weight for the electrics is, but its much better there than on the stern, IMHO.
With the 160 lb of thrust from the stern and bow electrics going full I can do about 3.5 knots, which is well below hull speed. I can do 7 knots with the 9.9. It seems that nearly 7 knots comes relatively quickly, and additional RPMs from the 9.9 don't give me much since I don't have enough power to plane. Obviously, I can't keep up with a strong tide (i.e. Tacoma Narrows Bridge can be 5 knots), or even probably a strong wind, with the electric. When there are bigger waves, the front electric will come out of the water, and thus isn't any real use under those conditions.
I only want the kicker to get me home if the 90 can't, say from the ocean for halibut or tuna. 6 knots should be good, about 4 or 5 hours, maybe a little more if I'm out for tuna. The 9.9 can do this nicely, but I hate the weight on the transom and the permanent list to starboard, which I currently counter with large batteries under the dinette on the port side. If I'm coming back from tuna, I'd obviously have extra fuel, be loaded with gear, coolers and ice. 100+ lb off the transom would be very useful.