Transom jacks

codprawn · 09 July 2004, 20:12

Anyone got any experience of fitting one of these? From what I can gather it helps quite a bit to be able to raise the outboard for speed and drop it down for thrust.

I saw one of the Honda press boats fitted with a nice looking setup - a cougar rib if my memory serves me right.

Also the setback can also help but is any of this worth doing on a leisure rib? If it saves some fuel then it has to be worth doing!

http://www.iboats.com/products/694/2...nsom_jack.html

This one looks a good price to me.

Matt · 09 July 2004, 21:51

Depends what you're putting it on. You need the right prop, some props will lose grip at quite low height. At very high transom heights you can also lose dynamic (prop driven) bow lift. But the additional set back on the engine gives you more static bow lift. You might need low water pickups on a very high transom height. It's only worth it on a pretty fast, light, hull.
It can reduce the tendency of the hull to roll as it gets airborne, but can increase the tendency to paddle wheel.

Having played with one, IMHO it's not worth it on a sub 50mph boat.
And it's only worth it at all if you want absolute top speed.
As always it's a compromise, though the hydraulic lifts are less so since they are adjustable on the move.
Just my humble opinion.
M

Searider · 09 July 2004, 22:11

There was one fitted to the K4+ RIB at Ribex.

Adam at K4+ sells this type of kit and might be worth speaking with.

www.k4plus.com

Regards

Duncan

codprawn · 09 July 2004, 22:39

Quote:

Originally Posted by MadMat

Having played with one, IMHO it's not worth it on a sub 50mph boat.
And it's only worth it at all if you want absolute top speed.
As always it's a compromise, though the hydraulic lifts are less so since they are adjustable on the move.
Just my humble opinion.
M

Does it help fuel economy? I should imagine it is bound to help a bit on the very rare occassions when you get flat calm water!!!

Matt · 09 July 2004, 22:51

Dunno, never paid attention to fuel economy.

stevetheboat · 10 July 2004, 03:57

Having run several boats in OCR & Offshore Racing over the years they are an absolute must when you are searching for the maximum speed but of little if any use in respect of economy - interestingly although virtually all "hard" boats use them for racing I have seen little evidence of Rib racers using them but do not know why this is unless they are not allowed under present race rules.

I would think that if you are soley looking to save fuel the time and effort put in to installing a jack (if indeed you have enough transom height to fit one) would be a waste. If however you are looking for speed this is a top tool.

Regards,

Stevetheboat

cider daze · 10 July 2004, 14:37

i run one on a 27 ft revenger had it for the last two years great tool, but be carefull i ran with mine right up during a race last year cornered to hard over she went. A friend of mine in a 8 m pascoe did the same 3 weeks ago.

codprawn · 10 July 2004, 21:10

Do I or don't I? mmm what a question - like the thought of it and anything that increases speed must have a benefit of saving fuel when you throttle back a bit - although with the extra speed would I???

Will just have to remember to drop the engine down for tight turns I suppose - don't fancy a flip!

Matt · 10 July 2004, 22:00

Obviously I don't know either you or your boat.
But, I would say you'll only see benefits from it if you are a fairly aggressive driver on a quick boat.
Cruising it won't make the slightest bit of difference to fuel consumption, and can even adversely affect handling, for the above reason, plus it will shift the boat CG rearward slightly which might not be what you want in a cruising scenario.

Tim M · 11 July 2004, 00:39

How much does it cost?