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Old 06 September 2004, 06:17   #11
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I was soooo hoping you were gonna comment on getting old spice aired out
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Old 06 September 2004, 06:17   #12
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Quote:
Originally Posted by Pete7
Rubbish.

JW hit the nail on the head, but also worth looking at engine height, high mounted engines do increase speed but when we tried it with a Yam 115 she lost grip to easily, result we put the engine back down a hole. Not a huge change in height but really did make a difference out on the water.

Peter
Which is why I am about to order a transom jack!!! More I think about it the better the idea seems!
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Old 06 September 2004, 06:18   #13
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Hydraulic or manual?
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Old 06 September 2004, 06:38   #14
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Quote:
Originally Posted by MadMat
I was soooo hoping you were gonna comment on getting old spice aired out
oh she can go airbourne , but she is an old girl so tend to drive her with a little TLC however doesn't suffer from ventilation problems like an outboard, but then it is a 16.75" dia prop turning quite slowly.

Pete
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Old 06 September 2004, 07:05   #15
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A good prop should be able to leave the water and then take a grip as it comes back in. In most cases, you should be applying power as the boat re-enters.
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Old 06 September 2004, 07:47   #16
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Stainless would be nice. Current prop is a genuine Tohatsu A18 which I think translates to 13.5 x 18. It needs to go up a pitch or 2 because I can max out on revs before WOT. The prop was not changed when the extre 20hp were added. If I go s/s I must be looking around 13-14 x 20-21.

Anyone know what else fits a Tohatsu spline?
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Old 06 September 2004, 08:01   #17
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Unless Porter boats are very light, it's not likely you'll want a 21" pitch on a 140hp engine on a 6.5mtr. 19ish max I would have thought.
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Old 06 September 2004, 08:52   #18
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JW
19" would seem nearer the mark. I was working on 18" +1" to bring revs down +1 to 2" for going stainless. Depends on what diameter I can swing though.
The dry weight is around 1000kg.
Time to re read all the prop threads 'cos this has been done to death before, and then phone round the suppliers.

I am now happy that my original question came down to trimmed out too much for the wave in question, fluffy prop and iffy driving.

Mr 7. I shall give Lee a ring. Are you going to Church' next Monday nite?
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Old 06 September 2004, 09:24   #19
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Hydraulic or manual?
Hyrdraulic of course!

http://www.cook-mfg.com

The PL65 - would 10" setback be too much with a 225hp on an 8.5m rib?
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Old 06 September 2004, 09:38   #20
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Difficult to say. Could be great for max top speed (with the right prop too), but worse in the sloppy stuff unless you start adding a bow tank, or other shiftable ballast. Do you have to trim up way above neutral at the moment to get max top speed? As always it's a compromise, but IMHO a good one if you are prepared to spend time setting the boat up around it. Just bolting it on you might well be disappointed.
I would also consider either a low water pickup on the gearcase or transom mounted water pickups, plus also a water pressure gauge on the dash. It'll be very easy to run the stock water pickups above the water when you are going for max top speed, assuming you have a prop that can handle running near the surface. (I'm assuming you are running a merc with stock gearcase). I guess you could just about get away with putting those flaps on the stock pickups which force feed the water, or I've read about some people blocking off the top 2 holes on the pickup too, but they always seem a bit marginal.
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