DIY static outboard bracket

smokeonthewater said:
Honestly I have to admit..... while I can't suggest it to anyone else as it is officially a BAD idea I would probably just run the 150 hp pre made plate.... Jus sayin
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X2.... Since most manufacturers build in a certain load above the rated safe load, and if money wasn't all that important, I'd tend to do the same thing. Understand this is NOT a recommendation, just sayin what I would probably do.
Much like me running a 18hp Kicker on an EZ-IN kicker bracket for several years even thought the bracket was only rated for 10hp. But then again, I've never considered myself as the brightest candle in the box... so what the heck do I know.... :head:
 
I think you are going to have trouble if you mix metals unless you can insulate that aluminum plate from the stainless angle, the plate will act like a sacrificial anode to the bracket, especially in saltwater.
 
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Not precisely. I asked how it should be built, and someone suggested to put a plate on the inside.

It's clear from this thread everything should be aluminum, and consensus appears that it isn't strictly needed. The force applied is greatest at the inside top bolts of the transom and the outside bottom bolts due to the whole thing essentially being a lever. The bolts are stainless only because aluminum bols aren't strong enough (if they even exist).

I personally am uncomfortable using angle for an engine this size, I would feel better if it were at least "c" channel. That is just my gut feel, no actual numbers to back that up. But I have looked at pictures of Z-Lock for comparison. Most notably, the hi jacker design (which resembles the angle design) is rated up to 150hp. For larger engines, the design changes. The amount of force needed to move 2000lbs of boat, plus 1000lbs of fuel, people, and gear has to be significant ... Plus it must apply some amount of torque due to the prop.

[EDIT] Just found this design that uses angle brackets here:
Machine Shop Goes up to 300hp, so maybe angle is OK. I am stopping by a metal place Friday to see what is available and what it costs.
 
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smokeonthewater said:
Honestly I have to admit..... while I can't suggest it to anyone else as it is officially a BAD idea I would probably just run the 150 hp pre made plate.... Jus sayin
Click to expand...

I understand the sentiment, but I am an (electronics) engineer working in the nuclear power industry. My design comfort level starts in the 30% to 50% margin range, and if I can talk people into a more robust solution, I will. Then I add a backup system. Actually, we like four backup systems for anything really critical.

It may work just fine for a long time. I understand perfectly well that T&H designed in margin, but I could never sleep well at night using something beyond rated capacity. Fukushima got hit by almost 10x worse than it was designed for, which has no bearing on this topic, but it does reinforce the idea that safety can never have enough margin.

While I appreciate the viewpoint, I'd never be comfortable with it
 
smokeonthewater said:
You know.... at $143 shipped THIS^ is another good option

If not you could use this design for yours..... only downside is a couple more holes n the transom.
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I'd use a 1" plate of aluminum! You know, to give myself some margin ... good idea, I'll price that out Friday, too.
 
peiserma said:
I'd use a 1" plate of aluminum! You know, to give myself some margin ... good idea, I'll price that out Friday, too.
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1" is BEYOND OVERKILL! They only use 3/4" plate for a dual engine bracket where the engien mounts to it. For what your doing, bite the bullet and go to ebay and buy a jack plate. I seen several manual ones on there for under $200. By the ime you buy a piece of plate, and do everything your talking about, you will be into it for just as much i bet.
 
THEFERMANATOR said:
1" is BEYOND OVERKILL! They only use 3/4" plate for a dual engine bracket where the engien mounts to it. For what your doing, bite the bullet and go to ebay and buy a jack plate. I seen several manual ones on there for under $200. By the ime you buy a piece of plate, and do everything your talking about, you will be into it for just as much i bet.
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I haven't mastered the art of conveying sarcasm on the internet yet, sorry.
 
THEFERMANATOR said:
1" is BEYOND OVERKILL! They only use 3/4" plate for a dual engine bracket where the engien mounts to it. For what your doing, bite the bullet and go to ebay and buy a jack plate. I seen several manual ones on there for under $200. By the ime you buy a piece of plate, and do everything your talking about, you will be into it for just as much i bet.
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So I took your suggestion and went to ebay and found a Vance JPL 4400 for $174. Never having heard of them, I looked up Vance and found their website and description of the jack plate here:
Vance JPL 4400.

There is a 3" setback version, too (JPL 4300). Both are rated for 225HP. $174 is their normal price! In stock and made in the USA (a plus in my book)

That price makes it pretty hard to justify DIY cost savings.
 
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Buy that thing. Looks to be a high quality piece.

Not to mention an American owned small business. I'd rather give the little guy a few more bucks.
 
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peiserma said:
I understand the sentiment, but I am an (electronics) engineer working in the nuclear power industry. My design comfort level starts in the 30% to 50% margin range, and if I can talk people into a more robust solution, I will. Then I add a backup system. Actually, we like four backup systems for anything really critical.

It may work just fine for a long time. I understand perfectly well that T&H designed in margin, but I could never sleep well at night using something beyond rated capacity. Fukushima got hit by almost 10x worse than it was designed for, which has no bearing on this topic, but it does reinforce the idea that safety can never have enough margin.

While I appreciate the viewpoint, I'd never be comfortable with it
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Hard to disagree with that, especially since I worked as a mechanical engineer/facilities mgr for the company that brought you 3 Mile Island and owns Forked River Nuke Facility. But you have to remember that we're talking compressive strength here, and for 6061 extruded aluminum angle it's 45,000. Since most of your forces are going to be compressive (The engine pushing against the angle which in turn pushes against the stern of the boat) you're going to have to go some to convince me that it's not safe to up the size of the engine. It's a long stretch from a nuke facility to an outboard bracket. Just sayin...

And yes, for the money, I would buy that mechanical jack plate. You can see the quality that went into the design and machining of it. Nicely rounded corners, all edges broken, etc. Def a piece of quality workmanship.
 
Got the new-to-me motor on the boat today. Not rigged yet. With the motor in the highest position, I think its pretty close to where it needs to be. Vance customer service answered my question within an hour or so. Actually Mr. Vance did (small shop). I get 1.5" minimum, plus and additional 4" of adjustable "up". So the jack plate will raise the motor between 1.5" and 5.5" I think it will work just fine.

I am ordering the JPL 4300 when they open up tomorrow. Good price, looks like a good product, responsive customer service, made in USA by a small business. They get my money and a plug on this site.

Will post pics when i get it and also when installed on the boat.

Thank you all so much for your replies to my questions.
 
Good to hear about the responsive customer service. Worth it's weight in gold these days.

Gonna post their site to the links section for the next guy who needs them.
 
Here are the promised pictures of the bracket and installed on the boat. I put the motor on the highest holes and set the jackplate 0.5" up. That puts the ventilation plate about 0.5" above the keel. I can move it up another 3.5" if needed.
 

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