I just purchased a 14' semi-v aluminum boat. The transom depth, from the bottom of the boat to the rail is

Question

about 16". How long should the motor shaft be, 15" or 20" ?

Answer 1

cavitation plate on motor should be 2 inches below the bottom of the boat!

Answer 2

there is a bit of variance in the boat manufacturing industry, and that is still considered a short transom

the short shaft motor is exactly what you need. long shaft will actually put more metal in the water, therefore resistance and will be slower not to mention an increased chance of hitting rocks with the prop.

that is a great size boat, good luck with it and have fun

Answer 3

IT DEPENDS ON WHERE YOU USE THE BOAT AND WHAT FOR. if you are using it in shallow water or just as a runabout the short one is best but if it is used as a yacht tender or in rougher water the longer one is more versatile, Hope this helps

Answer 4

if you put a short shaft 15" engine on a 16" transom the prop will be in the disturbed water coming off the back of the boat and will work at greatly reduced efficiency.....if at all!

Answer 5

The 15" is correct the 20 will drag an slow you down>As the transom is not straight up & down so the engine will set out and the water will come up to cavation plate>You can put dolfin fins on the engine also>I  jack mine up on the tramson so the spray from the lower unit dosen't come up the back>Bit more speed>