Best outboard motor bracket for transom

Moe · Post by **Moe** » Tue Apr 26, 2005 8:47 am

Sounds like the 14.5" travel should do it for you... get the skeg a coupla inches out of the water when up, and put the AV plate a couple of inches below the surface when down at hull speed and below.

A couple of things to consider when determining how high to mount it... The transom might not be vertical at hull speed and below, and certainly not when climbing the bow wave. The latter will put the motor closer to the water when up and deeper in the water when down. If the plate puts the motor further back from the boat when down than it is when up, it will be even a bit deeper than the lift would indicate due to the boat's trim angle when climbing the bow wave.

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Moe

Mark Prouty · Post by **Mark Prouty** » Tue Apr 26, 2005 10:01 am

Thanks,

I'll be installing this motor before the season gets rolling.

On a previous boat, I traveled with a motor mounted on the bracket. It bent the bracket. I'll avoid that mistake again.

Mark Prouty · Post by **Mark Prouty** » Wed Apr 27, 2005 6:02 pm

See this thread:

http://macgregorsailors.com/phpBB/viewt ... &&start=15

Mark Prouty · Post by **Mark Prouty** » Sat May 07, 2005 5:46 pm

Anybody that can help. I'm installing a kicker. The motor bracket is in the down position. Is this position correct? I'm thinking I need to lower the bracket some. I haven't drilled any holes yet.

Moe · Post by **Moe** » Sat May 07, 2005 6:15 pm

Mark, it's a little hard to tell where the AV plate is with respect to the waterline... and where the waterline actually is on your transom with that big motor on it. You're going to want the AV plate about 2" below the waterline... and not much lower if you want the skeg to clear when the bracket's in the up position.

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Moe

Mark Prouty · Post by **Mark Prouty** » Sat May 07, 2005 6:20 pm

Thanks Moe,

I'm putting her in the water tomorrow to check the waterline.
(I don't think the big motor lowers the back end much).

Rich Smith · Post by **Rich Smith** » Sat May 07, 2005 6:22 pm

Mark - You'd make Red Green proud with that duct tape!!! Of course he'd probably use that set up to grate cheese...

Moe · Post by **Moe** » Sat May 07, 2005 6:23 pm

That's the right way to do it!

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Moe

Mark Prouty · Post by **Mark Prouty** » Sat May 07, 2005 6:40 pm

Rich Smith wrote:Mark - You'd make Red Green proud with that duct tape!!! Of course he'd probably use that set up to grate cheese...

Humm

Greg · Post by **Greg** » Sat Jun 25, 2005 7:25 pm

Mark,
Do you get the 6hp installed? Is the bracket working out OK or would you go with the 4 stroke bracket (much bulkier) if you did it again? I would like to know the performance from the 6hp both on the Mac and on the dinghy. Other things have taken prioity over us getting the kicker/dinghy motor for now, but it will be a future addition.

Thanks,
Greg

ralphk · Post by **ralphk** » Mon Aug 29, 2005 9:54 am

Read this thread with much interest.

I have an 8 foot Portabote with 2.5 Hp Mariner 2 stroke engine. Mariner has a little plastic prop - I'm guessing 5- 1/2 inches in diameter.

I want to store the engine on a plate on the transom similiar to what has been posted.

The real goal is to get the outboard out of the cabin. The 30 lbs of engine can be easily handled from the dinghy and mounted.

Question: Is there any point in having a swing down kicker bracket for backup propulsion, or am I just kidding myself?

Chip Hindes · Post by **Chip Hindes** » Mon Aug 29, 2005 11:12 am

Yes and no.

Obviously there's a point to it.

My 4HP dinghy motor can power the big boat at about 5 knots through the water. But it's also it's quite a big PITA to get it right and it only works well in fairly favorable conditions.

My Nissan looks almost identical to the Tohatsu pictured above, fixed with duct tape.

The transom is surprisingly thin, 1/4" to more more than 3/8" in that location. IMO it was far too flexible to support the weight of the motor alone, let alone the motor driving the boat. I cut a hole for a 6" deck plate on the inside of the transom in order to get access behind where it was to be bolted. There is a lot of foam in that recess and stiffening ribs right through the middle of that area so I pulled out the foam in pieces and fabricated a two piece backer plate out of aluminum. Even with the large hole for the deck plate I couldn't reach past the ribs to put the nuts on the bottom mounting bolts, so I had to put those on from inside. Put as much of the foam back in before I put the deck plate on.

This first time I mounted the bracket I followed the instructions that came with it and ended up with the cavitation plate too high and a ventilation problem. I moved it down several inches, had to plug the holes, and it now works marginally well.

However, with its off center location, if the boat heels to port for nearly any reason, from windage on the side of the boat, to slightly off center weight distribution, crossing a wake, whatever, the motor will ventilate. And even with 11.5 inches travel on the bracket, in the up position if the boat heels more than a few degrees to starboard, the motor will drag.

It works, it might save my butt in an emergency as long as conditions are favorable (but isn't that the antithesis of "emergency?") I'm not sure I can recommend it.

Mark Prouty · Post by **Mark Prouty** » Mon Aug 29, 2005 1:04 pm

Greg wrote:Mark,
Do you get the 6hp installed? Is the bracket working out OK or would you go with the 4 stroke bracket (much bulkier) if you did it again? I would like to know the performance from the 6hp both on the Mac and on the dinghy. Other things have taken prioity over us getting the kicker/dinghy motor for now, but it will be a future addition.

Thanks,
Greg

Yes, I did get my bracket installed and my motor mounted. It works well for me. It comes up just high enough to get the motor out of the water when heeling. I used Starboard as a reinforcement on the inside of the transom. I put two layers of starboard on the outside so the motor would tilt in the up position; it needs to be a bit away from the transom to tilt. The bracket has worked well and supports the motor without a problem. I can power using the my 6hp outboard; although, large waves would probably make it cavitate.

It also doubles as a great dog hanger.

Hey thanks all for helping me with this project. I'm really a wimp when it comes to cutting into the boat. Because of the infomation I obtained here, I got it right the first time.

If anyone wants I can but photos in the mods section.

By the way, as has been mentioned there is a little retaining wall for the foam insulation at this spot inside the transom. I had to break through this to make it work. The back of my hands were battle blodied from that darn wall. Also forget using the supplied carrage bolt for the last inside bolt. I had to purchase a similar size bolt from the hardware store and tighten it from the outside.

ralphk · Post by **ralphk** » Tue Aug 30, 2005 3:33 am

Thanks Chip and Mark - You guys are gooood!

I've decided to go with a stationary bracket, keeping the little weedwacker outboard high & dry.

Since I'll be cutting into the starboard side of engine well to put in a backup plate and through-bolts anyway, I thought that might as well put that hull penetration to good use.

There is a moulded fire extinguisher holder cavity. very suitable for this location. I think that I saw the mod on this site.

PS
Mark - I'm with you when it comes to drilling!
Nearly every mod goes through a mockup phase.
Stick on with adhesive first - fine tuned over a couple of weeks prior to the permanent SS screws/3M5200 mount.

MacGregorSailors.com

MacGregorSailors.com

Best outboard motor bracket for transom