Need a prop...

[Grant]

Hey,

I had my 14 foot fletcher out for the first time last week since going frojm a 60 merc to a 90 merc.
I've currently got an aluminium 19' prop on it and its turns at about 5800-5900 rpm (probably 6k at a push), although its good for ski-ing I think I'm going to get a 21' stainless prop to get a bit more top end, does this sound ok? What sort of speed could i achieve with this prop?

Cheers

Grant

[MrRob]

if you had a 21p prop it would go slower.
Last time I went out my mate came with his fletcher 16 with an 80hp and 21p ally prop and it did 35mph which is fair for the size and power.
The larger the prop the harder it is for the engine to turn it. So a 21p prop you would get about 5400-5700ish at a guess.
Less rpm less speed.

[TheOrs]

My boat:

Fletcher 14'/75 Merc
21" pitch ally prop = 45mph
20" pitch stainless high five = 40mph

Your boat should easily turn a 21" pitch prop & you should get about 45mph top end.

Of course your 'holeshot' will be worse.

[Burty]

Originally posted by MrRob

Less rpm less speed.

errrrr, No!
where is peak power and safe max revs on a merc 90horse?
the larger the pitch yes the less revs but the further you travel per revolution

[JBP]

not sure on the prop size/pitch but our K400s (14' fletcher & standard Yamaha 40) return between 35-40 mph with 2up.

I think it's a 15"

Hope that helps