Jack plate or no jack plate?

flash · #1 03-26-2006, 02:20 AM

I have a 1991 yamaha vx 250 which is going on an armstrong bracket for my 23 project. It is a regular 30" set back bracket designed for twins, but I'm using it for a single because of the larger flotation tank. Do I use the hyd. jack plate I have or not with this bracket? My concern is that it will move the motor back another 6". Any thoughts guys? Thanks ahead of time!

Andrew

strick · #2 03-26-2006, 03:34 AM

How long is the shaft on that engine?

strick

Bryan A. · #3 03-26-2006, 07:36 AM

Sorry,I have no experience at all with brackets but plenty of guys here do. Strick is the master of brackets.

If you decide not to use the jack plate let me know if you are interested in selling it. I am in the market for one and I notice you are close.

ScottM · #4 03-26-2006, 09:39 AM

flash,
In this application, I don't see the benefit of a jack plate on a bracket unless you wanted to get into skinnier water than normal. Jack plates do work well though. My father put a manual 6" jack plate on his 23 Sceptre a few years ago moreso as an interim correction to a transom height issue than for performance gains (see pic below). However, he has found that the jack plate allows his boat to plane at lower speeds. It's not known if there is any fuel efficiency gains since he never really tracked that and at the time he put the jack plate on, he also repowered.

Snookerd · #5 03-26-2006, 10:50 PM

Flash- I bought my 23 with an Armstrong bracket for twins (225 Mercs currently) with jack plates. The boat has yet to be splashed, but from what I have learned thus far is that the motors can be too low and cause major drag on performance and the degree of damage from salt water(trim-tilt pump has been replaced already)intrusion goes up.

Finster · #6 03-26-2006, 11:03 PM

Flash, thats a tough question. It depends a lot on the bracket configuration, and then gets complicated.
I am guessing you motor is an XL (25") and your transom is 25"? As the formula goes, for every inch the motor is set back, the length of the shaft decreases by 1/2". For instance my Seavette has a 30" transom, my 300 merc had a 25" shaft. By setting that motor back 24" on a Gill bracket you could make it work. The only problem is, it's trial and error finding the right height to mount the bracket.

Hope this made sence and was a help.