twin 50hp outboard setup on 16 footer

[twin 50]

hi guys and girls!!
I am about to mount twin 50hp mariners on a aluminium 16 footer...Yes I know...NUTS!! But why not do it?? Battery, centre console and 70 litre underfloor tank mounted just past the half way mark on the boat to balance things out a little!!
My question is....where exactly should the cavitation plates on the outboards sit in relavance to the hull?
Motors are 96 model PTT if that helps!!

Thanks,
Andy.

 

[stackz]

Re: twin 50hp outboard setup on 16 footer

um, my only question is shouldnt one of them be reverse rotation? looks like both have the same type rotation props on them.

 

[Xandre]

Re: twin 50hp outboard setup on 16 footer

Wow that is bad ***!

Legal?

 

[Huron Angler]

Re: twin 50hp outboard setup on 16 footer

um, my only question is shouldnt one of them be reverse rotation? looks like both have the same type rotation props on them.

I agree...but a little torque steering makes it fun

What kind of performance are you expecting? Had it out yet?

 

[Xandre]

Re: twin 50hp outboard setup on 16 footer

If you put twin engines on a boat do they have to be the exact same motor/specs?

Is it unrealistic to have a 50 HP and a 30hp on the same boat? Unbalanced power?

 

[twin 50]

Re: twin 50hp outboard setup on 16 footer

I havn't had her out yet...(motors just sitting on there to see what it looked like) just finished painting it 20 minutes ago. Still waiting for my welder mate to turn up so I can brace the back of the transom....then the set up begins!! Wiring, feul tank, console,battery, bilge pump, lights and then the motors.
Torque steer should be fun alright, they are both the same engines and same rotation. They came off a 6 mtr plate alloy boat and he had no problems with his steering...might be different on this small boat.
As for the legal side of things, there is no boat code or serial number for my boat, so Yip she's legal. LMAO!!
Thanks bubba1235. thats what i was thinking, motors are 330mm apart so I can blot up to exising transom support on either side of where old single motor came off.
Im not sure about performance....it just looks mean as ?*^k so I had to do it, Its costing quite a bit to set it all up from scratch, but think it will be worth while.

 

[Star]

Re: twin 50hp outboard setup on 16 footer

Can anyone here say SWAMP! Too much weight ona low cut transom, or am I crazy?

 

[twin 50]

Re: twin 50hp outboard setup on 16 footer

hopefully no swamping..it has a VERY large well at the back and would need about 70mm (about 200mm over transom) before it takes on any water at all.....If it sinks to 900mm im ?**ked either way!! lol

 

[twin 50]

Re: twin 50hp outboard setup on 16 footer

****i meant 700mm**** not 70 mm.

 

[CharlieB]

Re: twin 50hp outboard setup on 16 footer

Couple thoughts;

First, cool facter, the twins are neat, making a great visual impression of a strong fast boat. I like it, a lot.

Mount the motors with the anti-ventilation plates even with or up to 1 inch with a line drawn straight back from the bottom of the hull at the width where the motors are mounted.

Now to address the performance. For sake of arguement, say the boat is rated and rigged for a single motor of 100 HP and has decent acceleration, top speed. etc. Mounting twin motors of 50 HP each will not achieve that same performance level, the additonal weight of the motors and drag of the additional gearcase will cause acceleration and top speed to suffer a measurable amount.

Remember this when testing performance, don't expect stellar performance, but otherwise it is going to be a great ride with outstanding handleing.

 

[twin 50]

Re: twin 50hp outboard setup on 16 footer

thanks charlieb,
yip understand the performance due to a single 100....It's all good, I'm really looking for the visual effect and having a different boat compared to most "small" boats out there (can't say I've ever seen a 16 footer with twins) Top end speed doesn't really bother me either, the waterways I use are VERY busy and only ever a chance for a full throttle blast every now and then. I think I will mount the anti-vent plates EVEN with the bottom of the transom at this stage and then maybe play later with lifting them that inch...Will have a few prop changes in between this too....I can't wait to see how it goes though...never had a boat with twins B4...REALLY LOOKING FORWARD TO IT!!

 

[Huron Angler]

Re: twin 50hp outboard setup on 16 footer

I've seen my model boat(16' Starcraft SS) with twin 35 OMCs bolted on.

They packaged a few from the factory that way for folks who like redundancy.

Also a great benefit is the capability to troll down with one motor slow enough to troll more easily.

Good luck with those twins!

 

[swamp-fox]

Re: twin 50hp outboard setup on 16 footer

I think I seen a you tube with a guy that had a old johnson 15hp and 10hp together. I didn't see the point in that. This is cool though keep us posted.

 

[cgervais]

Re: twin 50hp outboard setup on 16 footer

Twins are cool! My 16' SC came with twin 25hp Johnsons from the dealer, it work good.