SeaMount Marine Bracket
 

I've been looking to add a bracket to my 20MA. It has a 2012 Yamaha 150 4 stroke on the back and it seats stern heavy. I'm in the Tampa Bay Area and found a company up here called SeaMount Marine Products. I called them and they seem very knowledgeable. My Question is has anyone used them or know any info on them. Any info would help thanks

Colin Mattson has made two tanks for me and some custom made aluminum "emergency drain pans" for my A/C air handler. Good people, been around forever.

If it's stern heavy now, it will be much more so with a bracket. Even if you use a bracket with the maximum possible flotation (a Hermco), you're CG will be shifted aft when up on plane, so min planing speed, ride and load carrying ability will be worse than it is now. If you haven't already read it, I'd suggest you check out my post on the pros & cons of brackets.

Colin and Robyn Mattson are great people and do very good work. I've had them build fuel tanks for both my SeaCraft and Bertram. Both are "Vee" bottom tanks with a second or third pick up that is 1/4 lower than the engine pick ups. I have an extra hose and priming bulb on the "low" pick up and every six months or so I pump a little fuel out in case I buy or develop any water. Colin said send me a drawing of what uyopu want and I'll build it. He will build an oversized "floatation" bracket if you want him to. Kicker bracket, dive ladder etc., - no problem. I think the best option in the Bay Area, if you don't go with the Top Rated Hermco Fiberglass unit.

Make the tub as large as you can get it for flotation

Stern Heavy MA
 

Jonhybrid-
By all means you should check out Bushwacker's post on the pros and cons of adding a bracket. He has one and is candid about the changes he experienced. I suggest you also check out my post of Estimating CG Shift with Heavy Engines (about 9-24-16). You can judge how much CG shifted with a 4 stroke and how much more it will shift with the 4 stroke on a bracket.

Thank you everyone for for the information and from what I gathered I'm going to raise the motor and get the AV plate out of the water and look into an AV plate fin and maybe a stern lifting prop. Sounds like the bracket is going kill performance on the cruise n top end for me.

Recently had a bracket made by Colin for my 20sf, work is impeccable and completed on time!!! Be prepared for him to adjust designs without consulting you as he knows more about brackets than we do...In regards to flotation I have compared mine at rest to some photos of other manufactures brackets and do not see a difference with a 135 Opti...

bracket
 

quick pic

Although the amount flotation in a bracket at rest may determine whether or not a boat will self bail at the dock, the flotation advantage disappears when you're up on plane. The much more important metric is one that you can't see, i.e., what moving the motor ~30" further aft does to your boat's CG! Motor weight is a large part of that, so lightweight 2-strokes have a significant advantage for use on a bracket!

CG location/boat balance is the single most important factor affecting your boats performance, as that will determine min planing speed, how well it rides in a chop and the boat's tendency to porpoise.

Looks like Colin does a very nice fabrication job! However I don't understand why Armstrong and others give up so much flotation by angling the bracket up at the aft end instead of coming straight out like the Hermco shown below. Rather than trying to minimize drag in the "transition-to-planing" speed range that you spend little time in, I think Potter had a better idea when he designed the straight out bottom which, in addition to maximizing volume, also creates a "trim-tab" effect (additional stern lift) by being in the water when you're climbing up on plane. Don Herman used to make a living rigging production boats at a plant in Ft. Pierce, and that experience shows up in his clean rigging system that runs rigging through the flotation tank underneath the swim platform instead of across it.

bracket
 

yep one of our many discussions during the design phase, Collin's brackets set a little lower on the transom a do not have quite the lift as the Armstrong's towards the aft we also only have 26" of setback which still leaves about 3" of clearance with engine at full tilt. Rigging was personal preference based on a fear of large holes around the water line...sorry to hijack thread........