How Big

[stul]

Hi
got a 4 metre Narwhal rib,with a mariner 40 hp engine,would like a bit more power and speed max on flat water know about 25 knots(mph) gps read out,Advice please taken on what size of bigger engine,looking to buy second hand Narwhal have a deep hull and handles fairly well
Stuart

[Biggles]

Stul,

Not too sure of your situation, but if I were you I'd be looking at selling your present boat and buying something that could say take a 80 HP on the back. Might work out a better proposition than getting a few more MPH for spending a couple of grand to get a 50/60 HP reasonable engine then selling your present engine on for about a grand. Personally I'd be happy getting 25 Knots at sea, especially a moderate sea in a RIB. But to get 25 Knots in a moderate sea and have any teeth left your going to need a bigger boat. Something nearer 5 Meters then your present engine is going to be no good so as I said at the start your probably better off selling the whole lot and starting again but bigger.

Apologies if this isn't what you want to hear. Having said that if you can get a 50 HP 2 stroke in good condition I'm sure you will have a good time. Unfortunately second hand good condition 50 HP engines are hard to come by. I'd take a look at brand new Tohatsus. Good solid engines with a warranty.