New Props for 150 Optimax

jimc · 11 August 2005, 16:47

I am looking for new props for my 150hp Optimax.

Currently running a 19" Laser II, looking for:

a) Something to get more speed

b) Something for more grip in tight turns and pulling up skiers etc

Aware that this will be two different props.

Advice and sellers wellcome.

Many thanks,

James

simmons0 · 11 August 2005, 16:48

What rev's are you pulling at WOT with the 19" prop?

Nick Hearne · 11 August 2005, 16:58

What speed are you getting at the moment?
Give Julie a call at steel developments, very help full!
http://www.steeldevelopments.co.uk/

jimc · 11 August 2005, 17:03

Getting about 5500 revs fully trimmed and can make 46 knots with 4 in the boat, looking to go above the elusive 50 barrier!!

Nick Hearne · 11 August 2005, 17:07

Quote:

Originally Posted by jimc

Getting about 5500 revs fully trimmed and can make 46 knots with 4 in the boat, looking to go above the elusive 50 barrier!!

Clean & wax the hull , kick 3 people out!
Job done & saved £600 on new props

Daniel · 12 August 2005, 09:32

My Opti 150 max'es out at 5750, so you are not far off. The solent hull has a reputation for being quick but i'm not sure 50knts is attainable with a 150. Are you trimming right out to get these rev's?

I don't know a huge amount about different props but my simplastic view would say try a 17" laser II, try and borrow one if possiable. I don't have one i'm afraid.

I can make 46knts with a 21" laser II @ 5200 RPM and the same speed @ 5500 RPM with a 19", never tried a 17" so please report back if you try it.

Mollers · 12 August 2005, 11:51

If your pulling 5500 rpm and the opti maxes at 5750 then more speed cant be obtained. To gain the extra 250 rpm you'd need to fit either a smaller prop or one of a lesser pitch. This will give better pull out but less speed. Another trick is to lightly sand the hull with some fine wet and dry paper. 800 grit with soapy water is good. The top dinghy racers do this, it causes the hull it ride on a layer of minute bubbles which "releases" the hull and reduce drag. Waxing the hull tends to do the opposite and create suction between the hull and the water. It sounds as if 46 knts might be yer lot though.

Nick Hearne · 12 August 2005, 12:06

Quote:

Originally Posted by Mollulnan

If your pulling 5500 rpm and the opti maxes at 5750 then more speed cant be obtained. To gain the extra 250 rpm you'd need to fit either a smaller prop or one of a lesser pitch. This will give better pull out but less speed. Another trick is to lightly sand the hull with some fine wet and dry paper. 800 grit with soapy water is good. The top dinghy racers do this, it causes the hull it ride on a layer of minute bubbles which "releases" the hull and reduce drag. Waxing the hull tends to do the opposite and create suction between the hull and the water. It sounds as if 46 knts might be yer lot though.

So a sandy bottom goes faster hey

Mollers · 12 August 2005, 14:54

....may give you a rash also!

Quote:

Originally Posted by Nick Hearne

So a sandy bottom goes faster hey

Daniel · 12 August 2005, 14:56

My osprey is anti-fouled, often wondered how much this knocks the top speed.

Mollers · 12 August 2005, 15:29

Quote:

Originally Posted by Daniel

My osprey is anti-fouled, often wondered how much this knocks the top speed.

Next to nothing with a well applied "High speed" anti-fouling. A chunky missus onboard would be worse!!

rbw156 · 12 August 2005, 18:04

Yes, wet & dry can help, however, use 1000 or 1200 grade. Also, you must rub fore and aft, not across the hull (this would have the opposite effect!). Personally, I not do it as you will never get that lovely glossy finish again.

Mollers · 12 August 2005, 20:19

Quote:

Originally Posted by rbw156

Yes, wet & dry can help, however, use 1000 or 1200 grade. Also, you must rub fore and aft, not across the hull (this would have the opposite effect!). Personally, I not do it as you will never get that lovely glossy finish again.

If a rib is used for what it is intended (they aint yachts), then the "lovely glossy finish" doesn't last too long anyway. Staining from being left in the water un-antifouled is the biggest culprit.

brucehawsker · 12 September 2005, 21:41

We made 48.9 knots with Kev from Solent at the helm and just me hanging on for dear life at her acceptance trials. Never got above 46.5 with me at the helm.

Mollers · 12 September 2005, 21:53

I'm running a 19P Vengeance on my 150 Opti. It'll pull about 5300rpm which gives around 42knts on the gps. The pull out is instant and great for the kids wakeboarding. I'm in the process of buying a 21P for use when cruising. I cruise at about 3800rpm which gives approx 31knts with the 19P. Hopefully nearer 35knts for the same revs with the 21P.