Outboard Mounting Question

[actaeon9]

Hi All,

A friend of mine has a 1954 14' Lone Star Ski boat. It's the "Pleasure Boat" model with the small wrap-around windshield, I believe it's a Riveria model. He also has a Yamaha 150 Outboard (89 Model Year), that he was thinking about mounting on it. He knows this is a severe over-power and would never open it up like that. Our question was more of a weight issue. I believe the boat originally was rated for 35-70 HP motors. Back in 1959, wouldn't a 70 HP weigh about the same as an 1989 Yamaha 150? We thought about loading an non-working 150 he has into the back of the boat and test floating, but I thought I would ask for opinions here before going through all of that trouble .


Thanks in Advance for any help!

 

[ezmobee]

Re: Outboard Mounting Question

Let me just tell you, no one on here is going to give you any advice on mounting a 150 on a 14' boat. Just not gonna happen. And the weight difference between new and older motors is not what you expect. In fact in many cases the newer, more complicated motors are heavier! I don't personally care if you try this but I thought I'd warn you of the earfull you're about to get......

 

[Chris1956]

Re: Outboard Mounting Question

There will be no issue mounting that motor. The boat will sink immediately, by the stern!

In 1959 the large motors were the fat fifty which weighed in at 200# or so. that 150HP Johnny weighs about 350# or more.

That boat was meant to handle at most, a 35-40HP Big Twin Johnny that weighs 143#.

Actually your friend will likely get arrested driving that rig to the water.....

 

[Silvertip]

Re: Outboard Mounting Question

You said "he would never open it up like that". That is not very likely true and when he does, the transom will likely give way and he could be run over by his own motor. This is a very serious overpower issue which does not involve just engine weight. The transom on that boat was not designed to "support" much less tolerate the "pushing and twisting" forces a 150 will impart. Remember, at 150 at half throttle will likely be about 10 - 15% more power than an old 70. No insurance company would cover a liability issue in the event of an incident. With all due respect -- this is indeed a "bad" idea.

 

[actaeon9]

Re: Outboard Mounting Question

Thanks Guys, I completely agree. I just needed some backup info (like that the new motors actually weigh more) to argue him away from it.

Thanks again!

 

[tashasdaddy]

Re: Outboard Mounting Question

"Our question was more of a weight issue. I believe the boat originally was rated for 35-70 HP motors." that would never happen, they did not make motors that big in 1954. the largest motor Johnson/Evinrude made in 1954 was the 25 hp. even with twins that is only 50 hp. Mercury was just an infant in the outboard world.
http://www.old-omc.de/e_1954/seite_09_16.jpg

 

[Frank Acampora]

Re: Outboard Mounting Question

Speaking as an owner of a 14 footer with a 125 on the back, It is do-able, but not without some major modifications. First, the transom is most likely 15 inch and the engine is 20 inch. So, the transom must be raised and re-inforced to handle the power.

Second, the boat will likely shake itself apart at the speeds for which it was not designed and you will find yourself gluing it together constantly.

Third, She most likely will not sink but will sit extremely low at the stern and will almost always take water over the transom.

AND--MOST IMPORTANTLY-- outboard engines on boats like that have only one speed. You and I both know that your friend is going to open it up to see what she will do. Unfortunately, if he does it in a traffic area, he is likely to get into trouble. AND, Because of the weight distribution and design of the hull, he will not get the top speed he thinks he will. 150 Yammy--maybe 60-65 MPH. Consider that a 18-20 foot boat with a 175-200 Rude will go the same speed much more safely.

Should he do it? No! Will he do it? Maybe. If he does, he needs to put much thought and work into making it as safe as possible.

And speaking as one who has flipped several hulls, ALWAYS WEAR the PFD, and install a kill switch. These are absolute musts.

As one docter said to another when I was in the E.R. after a skiing accident: "How does someone so old get so crazy?" Other Dr. reply-- "No! How does someone so crazy get to be so old?"

 

[Home Cookin']

Re: Outboard Mounting Question

read the thread in "stupid human tricks" about a guy who has already beta-tested the big engine/ small boat combo. (test: unsat)