Futura prop size

Kernow Buoy · 29 October 2013, 17:29

Zodiac Futura Mk 2, 4.2m with yamaha 30, no diving kit usually 2 people on board, what size prop do we think?

Peter_C · 30 October 2013, 01:39

Get a tach, and take it for a full throttle spin. Then report your end results along with your current prop. There doesn't seem to be a given prop, it is more a discovery item.

Kernow Buoy · 30 October 2013, 07:25

That's the trouble Peter, there is no current prop! I've never used this boat so am after a best guess prop size.

RIB-Teccie · 30 October 2013, 07:37

For the futura, it would be best to find out which prop yamaha originally supplied as standard. Failing that, these props begin around a pitch of 8" and go up to 14". I would begin in the upper range of that as it is a sib and a bit lighter than a rib. My guess and it is only a guess would be around 11" or 12" pitch. Yamaha always supplied mid size as standard. It is always trial and error, especially when you have no starting point.

SIBRider · 30 October 2013, 16:14

What engine is it? Current F30 747cc? I would start with 14 or 15 then.

RIB-Teccie · 30 October 2013, 19:00

That's a point, I thought it was the one in the picture. Clearly not. My thoughts were for 3 cyl 2 stroke. Same rules apply though, yamaha usually supply mid size pitch to get things going.

captnjack · 30 October 2013, 19:39

Quote:

Originally Posted by RIB-Teccie

Yamaha always supplied mid size as standard.

Not on a 30hp, at least not in this country. Up to and including 25hp motors come with a standard prop but that's the largest size coming with a prop. Everything from there up is dealer selected in consultation with the owner based on the boat being fitted.

The range for that engine is 8 to 14" pitch.
http://www.yamahaoutboards.com/sites...20-%2030hp.pdf

I would go with a 13" pitch to start (be sure you have a tach fitted). While its a light boat with a light load they have a surprisingly large wetted surface. Don't spend the extra money on a "performance" prop since you are playing a guessing game to start anyway. Just get a standard prop with 9-7/8" diameter.

SIBRider · 30 October 2013, 19:42

Hmm I see no picture

RIB-Teccie · 30 October 2013, 20:04

Yep, my fault for replying with bleary eyes, I saw the picture on Pete's thread. Doh!!

Peter_C · 30 October 2013, 20:57

I run a 15" on mine and dropped down from a 17", but my diameter is probably larger, plus my engine is a dirty 2 stroke 40HP, and I scuba dive and haul heavy loads at times, so for me it is more about torque.

Do you have a shop around you that offers a trade in program for props?