Big Outboards mounted to back of transom?

[RonW]

I have been seeing more and more outboards mounted on the back of the transoms with brackets, and some really big ones. Like a 225 four stroke on the back of a 20 foot glass boat.
I could see where it would save interior room, but it also has to be really braced as it sure has to put a lot of pressure on the transom, and probably the most pressure while on the trailer going down the road.
So what is the opinions of such a outfit?
Was thinking of next boat being about 23 feet long with a 30 inch or so high transom,putting a 70 or 90 fourstroke on the transom with brackets would be nice.It should give the option to use whatever 20 inch shaft outboard you wish, as well as having a clean transom. Plus a fourstroke outside and down a little on the transom would have to be very quiet.

[paladin]

I got an aversion to such things.....I wuz cruizin off Maranduqe Island when I heard a roar....and was being overtaken by a Banca...about 40 feet or so with 4 big mercury black max motors on the stern and a dude with a tommy gun on the bow pointing my way.....I "souvinired" then one round from the M-79 I picked up on the black market in Thailand to assist them with a course correction.......

[Gresham CA]

Ron,
The advantages to these brackets are as you've aleady mentioned and also one that you don't want to hear. It gets the motor UP higher not lower. This improves motor performance and boat handleing.

[ 07-30-2004, 11:51 AM: Message edited by: Gresham CA ]

[Roger Stouff]

Ron,
I assume you're referring to what they call a jack plate. I have one on my &#&$*glass boat, an 18-foot Cajun fish & ski with a 175 Johnson. It's my understanding that moving the engine farther from the transom changes the problematics of cavitation, improves performance and allows her to be adjusted more finely. For instance, I can trim the engine down on my Cajun farther than if I didn't have the jack plate...the transom would stop it. This helps me "get out of the hole" quicker, get the nose down so I can see where I'm going!

[Gresham CA]

Roger, I think he is talking about those big fiberglass brackets that are on the back of a lot of Gradys and Boston Whalers.

http://www.gilmarine.com/products/gbracket/gild1.jpg

[ 07-30-2004, 01:45 PM: Message edited by: Gresham CA ]

[Donn]

Or, like this butt-ugly Scarab:

http://www.stainlessmarine.com/scarab.jpg

[RonW]

Or maybe something no so but ugly.

http://www.boatsofcharacter.com/downeast.html

Check out the photos, the center console model has a good view of what I am thinking of. In fact that is the boat that I am thinking of.

[Roger Stouff]

Originally posted by Gresham CA:
Roger, I think he is talking about those big fiberglass brackets that are on the back of a lot of Gradys and Boston Whalers.

http://www.gilmarine.com/products/gbracket/gild1.jpgYOWSUH! :(

[ahp]

What kind of dope are you planning on running?

[Bruce Hooke]

Is this the boat you are talking about RonW?

http://www.boatsofcharacter.com/original/images/de_pu/de_center.jpg

[RonW]

JACKPLATES - So that is what they are called.
Been doing some research on them, since I now know what they are.Here is a website for one manufacture that has some info and prices. Seem like about $1500. for a single.

http://www.portaproducts.com/bracket_inaction.html

These jackplates are quite interesting and looks like the next generation in mounting outboards.Appearantly they dramatically improve outboard performance by getting the motor back and out of turbulence caused from the hull.Not to mention a clean transom without the traditional slop well. Neat -THANKS...

[RonW]

YEA MAN- that is the boat I am talking about, see how the outboard just kinda follows the boat around.
I could not copy and paste the picture, don't know what I was doing wrong, is there a secret to pasting pictures on this board?

Thanks for posting the picture for me Bruce...

[ 07-31-2004, 09:29 AM: Message edited by: RonW ]

[Bruce Hooke]

Originally posted by RonW:
YEA MAN- that is the boat I am talking about, see how the outboard just kinda follows the boat around.
I could not copy and paste the picture, don't know what I was doing wrong, is there a secret to pasting pictures on this board?

Thanks for posting the picture for me Bruce...Right click on the picture and select "properties". Amongst the properties there should be a URL (path)...something that starts with http. Select this URL and hit Control+C to copy it. Then get back to your post on the forum and click the image button and hit Control+V to paste the URL when it asks for the URL. Note: These are instructions for a PC. If you have a Mac somebody else will need to help you because I can't remember how to do some of the key steps on a Mac.

[RonW]

http://www.boatsofcharacter.com/original/images/de_pu/de_center.jpg

See if this works.....
computer course 101........

[ 07-31-2004, 11:24 AM: Message edited by: RonW ]

[warthog5]

This is something that I know somethig about.
There are 2 manufactures that make fiberglass motor brackets [Hemco & Seamark]and several that make alum. one's.[Armstrong, D&D Marine, Gil & Stainless Marine]
[Note] The one's made by Stainless Marine are NOT Stainless.

A motor bracket is not to be confused with a Jackplate. It's a diffent animal, but can be used in conjuction with a motor bracket. That is usually done because someone droped the ball in enginering the setup. Bob's Machine Shop Jackplate is one of the best if not the best. I own one.

http://www.bobsmachine.com/transomjack3.gif

Want to know more about brackets? Read this.
http://continuouswave.com/whaler/reference/engineBra ckets.html (http://continuouswave.com/whaler/reference/engineBrackets.html)

Manufactures of alum motor brackets can be found here. I have a D&D Marine for my other project.
http://www.dadmarine.com/index00.htm
look down the page where it say's "Visit Our Competitors".

Pix of D&D twin bracket w/wide body/tub to support twin 4 strokes.

http://www.classicmako.com/projects/xshark/images/bracket7.jpg

http://www.classicmako.com/projects/xshark/images/bracket3.jpg

http://www.classicmako.com/projects/xshark/images/bracket5.jpg

[ 08-01-2004, 12:52 AM: Message edited by: warthog5 ]

[Andreas Jordahl Rhude]

Was out on Lake Minnetonka yesterday with friends (1964 Chris-Craft Sea Skiff 28 ft lapstrake inboard) and saw a new glass cigarette boat. She had twin 300 HP outboards on a jack plate type set up. One ugly vessel!

[Paul H]

The downside is that in addition to the added stresses to the transom, is the change in balance to the hull. Unless the hull is designed to have all that weight way back there, then you are going to be adversely effecting the hydrodynamic balance of the boat.

I'd much rather have a boat two feet longer then hanging the engine way out there. Perhaps there are some tax or insurance benefits? Sounds like more of an item for a racing boat. I dunno, I'd just as well have the additional flotation provided by the longer hull.

Four strokes are relatively quiet as it is, so I don't think there will be much noise reduction. If you are looking at any offshore use, I'd be more concerned about the power head getting dunked, especially if you go with a 20" shaft. Remember, the wave has to get to transom before the boat rises, might be enough to dose the head before it bobs up and out of the way of a wave.