Bargain jackplate

codprawn · 17 October 2006, 22:00

http://www.boatsandoutboards.co.uk/view/F120933/

Just spotted this - it is the manual version but may be of use to someone - gives 10" setback.

ollyit · 18 October 2006, 11:36

they also look the nuts in persion opinion of course!

codprawn · 18 October 2006, 12:01

Mine is great - you can drop the engine down for tight turns and jack it up for top speed - also gives more room in the boat.

ollyit · 18 October 2006, 12:04

how is it controlled via a switch i assume?

codprawn · 18 October 2006, 12:42

Yes a rocker switch along with a position guage. The one listed is a manual one - controlled via a ratchet spanner I think. Useful for getting height correct but no good for playing with on the move!!!

richardjawilson · 19 October 2006, 23:08

other than height adjustment which I can understand, what is the advantage of having a 10'' set back?? I dont have any experience of racing boat setup and would be interested to know the benefit these make to handling and speed etc

richard

codprawn · 19 October 2006, 23:32

To be honest the MAIN reason I wanted 10" of setback was to get a rear bench seat in - shame the boat builder didn't do it!!! It still gives more room in the boat though.

The main advantage stated is that the prop runs in less disturbed water clear of the hull.

Cookee · 20 October 2006, 11:06

Quote:

Originally Posted by richardjawilson

other than height adjustment which I can understand, what is the advantage of having a 10'' set back?? I dont have any experience of racing boat setup and would be interested to know the benefit these make to handling and speed etc

richard

Whilst the water may be less disturbed further back and give you more room in the boat, many boats benefit from having the engine further back by giving better pitch stability without lengthening the hull, and in a race setup you can have the engine run higher which gives less drag.

I would suggest that for most people the extra speed gain would be very small below 50 mph, and the gains in pitch stability would not be worth the extra cost.

Some boats do not gain much significant benefit at all - Ian Sterlings Phantom 21 with an XR2 - 200hp on it has it bolted to the transom and reguarly beats the Batboats in the rough!

jwalker · 20 October 2006, 11:37

Quote:

Originally Posted by Cookee

...and in a race setup you can have the engine run higher which gives less drag.

Cookee, what's going on in the water that allows the motor to be lifted further? I can see why it is raised because the water is also rising from the transom.

Cookee · 20 October 2006, 12:08

Quote:

Originally Posted by jwalker

Cookee, what's going on in the water that allows the motor to be lifted further? I can see why it is raised because the water is also rising from the transom.

Not sure of the physics, but the water does rise from the transom allowing you to lift the engine higher in relation the the bottom of the transom - this results in less drag from the gearbox and higher rpm or bigger props - maybe it's the angle the water comes up at the gearbox?

codprawn · 20 October 2006, 12:20

I should think there is a low pressure area directly behind the transomn which causes the water to rise and that is what your prop is running in - the higher you raise the engine though the more you need things like low water pickups and surface piercing props.

What sort of props are you using Cookee???

Cookee · 20 October 2006, 12:41

Quote:

Originally Posted by codprawn

I should think there is a low pressure area directly behind the transomn which causes the water to rise and that is what your prop is running in - the higher you raise the engine though the more you need things like low water pickups and surface piercing props.

What sort of props are you using Cookee???

That's one of the reasons for moving the engine back - you can run it higher with the same gearbox.

Of course we run sportmaster gearboxes with low water pickups as standard, but we modifyu them again by extending the gearbox forward and shaping it slightly - it also gives better cornering. We actually use a Tempest for the race boat, a little thinned and tuned of course! A standard Tempest works well on the leisure boat with a 250 Verado as well! This is also on one of our custom cast brackets but a lot lower!

codprawn · 20 October 2006, 13:07

On a heavier boat would the sport master still be the one to have? I see the sport master is best for boats getting over 85mph - a speed I will never see!!!

Cookee · 21 October 2006, 11:38

Quote:

Originally Posted by codprawn

On a heavier boat would the sport master still be the one to have? I see the sport master is best for boats getting over 85mph - a speed I will never see!!!

Weight has nothing to do with it - every hull, engine and prop is different and then you have engine heights etc ...... We had problems with a CLE at around 70mph on our race boat and stuck a blow out ring on which helped - it still wasn't as fast as the Sportmaster so we went with that option - our genuine race speed with the XS200 is around 73mph and we have to have a low water pickup to get the engine high enough to do those speeds - I would therefore disagree with the 85mph comment.

Unless you are lacking in water pressure or seing (much) higher speeds than you already are then a Sportmaster or a CLE would be a waste of time.

I said before you got your boat a lifter would not be of any great benefit, and I suspect it only makes a small differance in speed (if any), and if you talk to any racer they would much rather be without them as they are just one more thing that can go wrong!

codprawn · 21 October 2006, 12:21

Quote:

Originally Posted by Cookee

Weight has nothing to do with it - every hull, engine and prop is different and then you have engine heights etc ...... We had problems with a CLE at around 70mph on our race boat and stuck a blow out ring on which helped - it still wasn't as fast as the Sportmaster so we went with that option - our genuine race speed with the XS200 is around 73mph and we have to have a low water pickup to get the engine high enough to do those speeds - I would therefore disagree with the 85mph comment.

Unless you are lacking in water pressure or seing (much) higher speeds than you already are then a Sportmaster or a CLE would be a waste of time.

I said before you got your boat a lifter would not be of any great benefit, and I suspect it only makes a small differance in speed (if any), and if you talk to any racer they would much rather be without them as they are just one more thing that can go wrong!

85mph is what Mercury say on their website - nowt to do with me.

http://www.mercuryracing.com/product...plications.php

Just trying to work out what gearcase would be best if I get mysefl a 300XS???

As I said before the reason I went for a lifter was because it also gave me 10" of setback to get a rear bench seat in - they didn't fit it for me though!!! There is one HUGE benefit of a lifter though - it helps a lot for me to get back into our stupid harbour - it is so shallow you wouldn't believe!!!