Twin outboards, and other crazy ideas, I need some input

[WalleyeGuy11]

Howdy all.
I am in the process of rebuilding my boat, and I have come up with a few ideas to really make it my own.

First off i am wanting to build a transom extension/offshore bracket to free up as much space as possible in the passenger area.

Second, I would like to mount twin 35hp outboards on the back.
Now I realize that there is no real advantage to running twins, and they would weigh more than one 70hp outboard. I'm just looking for some one who has mounted twins on a 16ft aluminum boat.

Also when it comes to the offshore bracket/transom extension. Has anyone done this themselves? Anyone have any pictures?

I have heard all the nay sayers explaining how its not worth it, but I could really care less to hear anymore about it.
I would really like some positive feedback and pictures on the matter.
thanks

 

[Woodonglass]

Offshore bracket for a 16ft Aluminum boat and then mount twin 35's on it. You really need to investigate the design and effect this would have on the boat. How would a Bracket give you more room? An outboard doesn't take up any OnBoard Space does it? The reason you've had naysayers is that they KNOW this is not going to work. We had one guy on here several years ago that tried fabricating his own Bracket. Spent a LOT of money on aluminium and it did NOT work. He finally gave up on it. Experience IS a Great Teacher!

 

[WalleyeGuy11]

Well, mounting the outboard off of the transom would allow me to get rid of the splashwell which would give me about a total of 2 extra feet.

I just don't understand why adding a bracket to a large boat would be any different from putting one on a small boat.

On top of that, adding something like what is attached should add for more flotation and stability in theory.

 

[BWR1953]

It's your boat so do whatever you like. I am! Gonna put a pair of 70s on my Chieftain (once I get the work started) just because I can! And I already have the engines. So there, naysayers! :mushroom:

Is your boat rated for 70HP? My Chief is rated to 150HP so the 140HP from the twins keeps me legal.

There are plenty of Youtube videos of boats that have twin outboards. Are you planning on tiller or remote steering?

 

[Woodonglass]

This forum has some of the most experienced and expert restoration experts anywhere in the world. I am NOT an expert on aluminium boats but we have several members that are. Hopefully they'll come aboard and offer their thoughts. I'm not certain, but I'm thinking that just about anything and everything has been discussed and tried and results have been varied. We have always stressed safety first and just because you can do something doesn't mean it will be safe. That's why Marine Engineers still have jobs. Hull design, Weight, Power etc all play a major role in how a boat performs and if it will be safe.
What kind of 16' aluminium boat do you have?

But...

Like I've always said...It's your boat and you can do as you see fit. ​

 

[mickyryan]

almost every person i have spoken to about making a bracket for a small boat said the boat rode terrible after, i assume it is because it shifts the cog way back and makes the boat ride funny. wider boats do better but even then a total false transom with flotation is better then the skinny ones , again this was discussions not anything i have done, i looked into it but felt the risk wasnt worth the small rewards and i am sticking with a i/o as originally built.
However, i will not try to dissuade you, as i do oddshit myself and sometimes it works sometimes it don't all i can say is make sure its safe and report back you might be the guy that starts a trend or you just come back and go meh it sucked either way good luck , if you cant find pics its because maybe you the first

 

[WalleyeGuy11]

BWR1953, my boat is rated for 90hp, but it's a weight issue, and it would be a remote steering setup, and I planned on getting a dual throttle setup. I've looked all over the web for twin 35hp or 40hp outboards but can't find anything on the matter.

WoodonGlass, my boat is a 16ft starcraft.
I also planned on moving the dash consoles forward about 15 inches and adding a larger fuel tank to counter the weight a bit. One idea I had was to find the center balancing point with the 40hp Johnson it has on it already and then go from there in the building process.

 

[WalleyeGuy11]

MickyRyan, thank you for your reply, below is kinda what I had in mind, just with a bracket to allow twin outboards to be mounted. I appreciate it, most people I've gotten replies from in the past on the subject weren't necessarily just turning down the idea, but had a tendency to get mean about it.

 

[MTboatguy]

Most of us that have been doing this a long time, don't say don't do it because it is dumb, we say it because a lot of us have known or seen guys who have tried it and failed. Crazy ideas today make for normal ideas in the future, but when we have witness something not working and somebody asks about it again, we are obligated to let you know what we have seen or experienced in the past.

I can say, joing a system like this and being a newer member, presenting an idea and saying you don't want to hear the negatives, but only the positives of what you want to do in your mind is a bit forward and closed minded. There is a way to make friends and there is a way to just get people to ignore you.

Anyway, good luck on your project.

 

[Old Ironmaker]

My dear Grand Father used to say if you have enough money you can make Niagara Falls run backwards. Can something be done, almost anything especially forward thinking outside the box and an unlimited budget. Should something be done just to prove it can be, at what cost? That's my take. I know a retired engineer I worked with, he did almost exactly the same thing. He salvaged a 15' tinny without a motor, he had a 9.9 and salvaged another. He did do what you intend on doing, including moving the helm forward to accommodate 2 separate tanks as he couldn't get a proper fuel distribution sharing a single tank. He could never tune the 9.9's to work well in unison. Had to go back to dual throttle and was constantly adjusting each and fighting the wheel to keep the boat straight. It was off balance and ran like a slug. But he did it, good for him. He disproved all the naysayers, so he claimed.

 

[Woodonglass]

A TRUE twin motor setup has one motor spinning the opposite of the other to keep the boat running straight. I've heard you can make outboards run in the reverse direction but I'm not sure how it's done.

 

[kcassells]

You can buy a prefabbed transom bracket for less than building one. Touch base with any bracket mfg. In addition with your boat they will either say it's possible or not. Thats a good way to learn for free if it makes sense.

 

[dingbat]

I’m guessing it could’ve done but at what cost? Probably more cost effective to just buy a 18’ boat.

Brackets have some good performance characteristics but they also have a number of not so desirable characteristics.

A bracket on my boat is a factory option. I went back and forth a number of times if thhe good outweighed the bad.

Improved ride quality and fuel economy verse poor handling around docks, issues backing down in rough water and the inability to tilt the motor enough to get the LU out of the water to name a few.

In the end, a ideal came up on a boat without a bracket so I went that way. I’ve since spent a lot of time running the bracketed version as well. I’m happy with my decision