maby the wrong place for my post in this big forum, but its a SIB so i put it here
A know some about prop sizes and pitch, but when i try the different props out on the boat I don’t get the expected result.
The boat, Zodiac futura mk 2, 40 hp mercury 2t, on a normal day loaded a bit of gear and a two person crew.
we got the boat with a 10-1/2" x p13 prop top speed WOT (5500 rpm) 43 km h or 27 MPH which is ok according to the manual that states 23-29 MPH with that prop.
That was great the first week but we soon wanted more speed, and it did a lot of blowouts or spinouts... it seemed like the engine had much more power.
so we went with a 10 x p16 supposed to get us going at 30-36 MPH acording to the manual, the day came with much excitement, but what a great fail... WOT (5500 rpm) no problem... but it was slightly slower and with more prop spinouts the same 43 km h or 27 MPH was recorded!
speed was recorded on GPS bough times... i don’t understand that the 10 x p16 doesn’t give us the speed we want... the 10xp16 looks a lot smaller than the 10-1/2xp13, maby just the pitch doing that,,,
so we are back at looking at props, with 2 new unwanted on our hands.
im lost and don’t know what to get, is it the boat? Its well inflated and engine run great! i have heard ppl. saying they go a lot faster with same boat and engine!
im looking at a these atm.
I found a used 13 x p17 that will fit... i know its big but will it work? im thinking no spinout and the pitch must be high enough to make the engine struggle to reach its rated rpm ie. high speed, but maby not healty for the engine..
I hope someone has an input thx!