boat propeller

I have a 23 foot colvic searider which has an 8 feet beam and a 80 hp ford
sabre engine on shaft.The boat is a semi displacement[close to nelson type
hull]and goes at 9 knots full [was used in harbour for moving boats]speed
and tick over is 3.2 knots[max rpm is 2500 boat weighs 2.5 tonne].I think
the boat should go faster than this and need to know how to find out the
pitch if that is possible and find a suitable prop to max my speed.The
people I brought the boat of had a bigger prop but could not find it after I
brought the boat.
Help would be much appreciated Andy

On Mon, 9 May 2005 20:29:10 +0100, "andy barnes"
<andy DeleteThis @barnesandy.wanadoo.co.uk> wrote:

>I have a 23 foot colvic searider which has an 8 feet beam and a 80 hp ford
>sabre engine on shaft.The boat is a semi displacement[close to nelson type
>hull]and goes at 9 knots full [was used in harbour for moving boats]speed
>and tick over is 3.2 knots[max rpm is 2500 boat weighs 2.5 tonne].I think
>the boat should go faster than this and need to know how to find out the
>pitch if that is possible and find a suitable prop to max my speed.The
>people I brought the boat of had a bigger prop but could not find it after I
>brought the boat.
>Help would be much appreciated Andy
>
The diameter and pitch are usually stamped on the boss of the
propellor, but possibly hidden behind the retaining nut.
e.g. 20x18 means 20" diameterx 18" pitch.
There used to be a calculation prog for props on Guy Fawkes's site
www.surfbaud.co.uk (I think !)
Hope this helps

scomber3