I had the mr shifta 2 forward and reverse to move my 5.8 vipermax and to be honest it strugled hold on a slight incline, so i sold it. It was fine moving a twin wheel caravan,
so i can only assume the boat was two heavy, and as previously stated they weigh about 60/70 kg. so arent the lighteast thing to lug about.
and at £ 700.00 new not cheap either.the only way is to try one, and see how it works for u.