Engine jack plates

Ezgoing · 03 January 2008, 22:16

Hi guys

any body experience of enginejack plates?

views welcome on efects on boat handling, lateral movement, vertical movement, weight, max horse power, etc.

I am considering one for a Suzuki 300df.

thks

PeterR · 03 January 2008, 22:23

I know Cookie will be able to give you some valuable advive .Perhaps you could PM him

Downhilldai · 03 January 2008, 23:58

Codprawn's got one too: a jack for a jack

codprawn · 04 January 2008, 00:04

Quote:

Originally Posted by Downhilldai

Codprawn's got one too: a jack for a jack

Oi mush!!!

Yes I have the CMC with 10" of setback. It is a nice bit of kit and despite what certain people said my engine still hasn't fallen off..........

I have a big problem with mine - the idiot who fitted it mounted the engine so that it was in the normal position right at the top of travel - so I have no real adjustment on it!!! I am taking my boat out of the water as soon as my trailer is ready and will mount the engine properly.

Remember if you fit one to install a water pressure gauge ao that you know if you have lifted the engine too high.

I suspect that jacks don't make that much of a difference but the setback is handy as you get more room in the boat and it's great to be able to get the engine high up in shallow water!!!

Cookee · 04 January 2008, 10:39

Quote:

Originally Posted by Ezgoing

Hi guys

any body experience of enginejack plates?

views welcome on efects on boat handling, lateral movement, vertical movement, weight, max horse power, etc.

I am considering one for a Suzuki 300df.

thks

Contrary to what Codprawn says they do make a big difference in a properly setup boat!

We use them for racing, but they are expensive items which require maintenance. If you are looking for setback or extra room I would fit a fixed bracket - zero maintenance and same effect. We offer a reasonably priced cast one now!

What do you get for your trouble? A definite increase in top speed, although this will be limited if you don't have a standard gearbox as you will lose water pressure if you lift the engine high enough to gain the full advantage. Other extra benefit would be in shallow water.

If you still want one the Stainless Marine Gorilla 3 is the one I would recommend, but a 300DF is a big lump with a lot of torque, and you would have to be considerate to it! It has fewer parts and requires less maintenance than other makes, and in racing that is the one the majority of racers fit, and believe me we can destroy equipment!

Codders is right about the pressure gauge - if your engine doesn't have one fit one - it might be good to have a separate one anyway.

codprawn · 04 January 2008, 18:20

Yes in a racing boat but I suspect the difference is smaller in a cruiser. Of course I don't really know until I adjust my mountings!!!

Ezgoing · 04 January 2008, 22:39

Has anyone tried one with 300 hp?

Nos4r2 · 05 January 2008, 12:27

If you're using a jackplate, is there a noticeable difference in the way using the trim affects the handling to not having a jackplate?

Robbie Diesel · 05 January 2008, 18:52

My first post so go easy! Yes, I have fitted a jackplate to my Boat, a Tornado 7.5 with Yamaha 300. Its a Bobs Machine Shop one with 6" setback supplied by Steel Developments and the gains are quite small, but they are there. On my setup i picked up around 3-4 mph top speed and it has helped cruise aswell. It now tops out at 64mph burning 100 litres an hour(YIKES)! And will cruise with a light load (2 people 100 litres fuel onboard) at 30mph burning 32litres an hour. But when loaded for long cruise with 300 litres plus 4 crew its more like 36 litres an hour at 30 mph. Prop is a Mercury Tempest 23". Hope This Helps

roofer · 05 January 2008, 20:58

Quote:

Originally Posted by Ezgoing

Has anyone tried one with 300 hp?

I used a Gorilla jackplate on my cat which was fitted with a 300 promax and had no problems.

Matt · 05 January 2008, 22:58

What Cookee said. Gorilla 3 are the strongest, but he does test things to destruction. Mention his name to stainless marine and they roll their eyes!

Cookee · 07 January 2008, 13:24

Quote:

Originally Posted by Nos4r2

If you're using a jackplate, is there a noticeable difference in the way using the trim affects the handling to not having a jackplate?

Actually raising the engine gives the boat less bow lift making the boat run flatter as the thrust is more in line with the keel than when it's down.

The trim has pretty much the same effect up or down.

Matt is right - I am partly responsible for the short life of the Gorilla 2, and the design of the Gorilla 3!

Bertus · 07 January 2008, 22:36

The site of stainless only show the gorilla II. Whats different on the Gorilla III?

Cookee · 07 January 2008, 23:02

Quote:

Originally Posted by Bertus

The site of stainless only show the gorilla II. Whats different on the Gorilla III?

Yup that's the one I broke / trashed / wrecked in Cardiff Bay in no time flat - the Gorilla III is a cross between the original and the II - it has mirror image halves that slot together without any bolts making it very strong. I have broken enough other types to know which is the toughest!

Nos4r2 · 07 January 2008, 23:13

Quote:

Originally Posted by Cookee

Actually raising the engine gives the boat less bow lift making the boat run flatter as the thrust is more in line with the keel than when it's down.

So, (I guess you're the wrong person to ask about fuel economy!

) does it follow that fuel usage drops when the engine is raised or is any difference in economy so negligible as to be unnoticeable?

Bertus · 07 January 2008, 23:23

I also considering a jack plate for performance and to set the engine back to create more space at the mirror but is it creating a lot more stress on the mirror?

Cookee · 08 January 2008, 13:06

Quote:

Originally Posted by Nos4r2

So, (I guess you're the wrong person to ask about fuel economy!

) does it follow that fuel usage drops when the engine is raised or is any difference in economy so negligible as to be unnoticeable?

In theory the fuel useage would only decrease if you used the decrease in drag to keep the same speed and throttled back a little - as you can imagine it's not an area that I have any practical experience in, but the high cost of the lifter and the small savings would not make it an economical excercise. If you want to save fuel go slower!

Bertus - If I assume you mean transom instead of mirror, then it would add the weight of the bracket to that of the engine, so you must find out if the hull will cope with the extra weight. The extra stress from moving the engine back would be small - best thing would be to contact the manufacturer.

Bertus · 08 January 2008, 19:04

Cookee, transom is the correct word. In Holland they say mirror(spiegel) The boat is rated for a 120 hp max outboard but I spoke a fire brigade in Germany with the same Rib and a 150 hp Johnson and they had no problems with it.
But, yes But, I think the wood is a bit wet and I need a transom repair.

But before beginning with that would like to now what to do and what I want. and what is on the market.

yorfuoj · 09 January 2008, 09:12

for a 300 Suzuki, and/or racing, I would just accept the Gorilla 3.
I used the Gorilla 2, which is perfect, but I added a point of Tig solder to avoid any chance to have the studs unscrew.

The big plus of Stainless Marine lift is that the motor is fixed by 8 studs - instead of 4 - to the plate, and the plate is fixed to the transom by 8 studs too .
Other jack plates have 4 in standard, so the stress is much better shared in SM.
Plus the studs are not screwed directly into the aluminium plate, but into stainless steel inserts - that is where I added the solder point for safety.

For less power and standard use, I would use the Cook-CMC - it is perfect - but there are a lot of other marks I didn't check.

Concerning the performance, it depends on the hull : I gained 8 knots on a 600 Prestige italian catamaran, just moving the 150hp Mercury motor from the "down" to the "near up".
I didn't check the fuel saving, but if one gains 8 knots with the same power, it is clearly more efficient.

Water pressure indicator is a must indeed ! I made it with a 35mph speedometer, larger than standard pressure ones.

Jorgos · 18 March 2009, 12:32

I have fitted a power lift on my 8 metres double stepped rib and Evinrude etec 250 . i did not have flat sea to check the full speed but i gained 1,5 knots on 4000 rpm and 10% more economy.

The question is the following. I was expecting that by lifting the engine to decrease the drague of the engine leg and increase the speed. In reality by lifting the engine the boat becomes slower because it gets the stern more into the water. On the lowest position i got fantastic economy and speed.
Maybe on the top speed is different the characteristics?