How to determine transom strength?

[dpropson]

I just bought a '59, 16 foot wood boat. It looks like new, very solid. How do I determine how large an outboard to put on the boat? Is weight or hp more important? I want to go big, but not as to danger the old woody. I'm not looking to break speed records just run around the lake. The boat is a runabout type. Thanks always.<br /><br />Dennis

 

[SCO]

Re: How to determine transom strength?

There is a coast guard publication guide for determining power for a homebuilt. It was discussed a few months ago on this board. Search the board for things like "Coast Guard", "Max hp", "power" etc.

 

[rickdb1boat]

Re: How to determine transom strength?

Weight is more important, but HP is also significant. I would say you could get away with a 30-40 HP with no problem, if the transom is solid. But best to check and find out for sure, as different hull designs call for different Max. HP.

 

[rickdb1boat]

Re: How to determine transom strength?

Try Here:<br /><br /> web pageor<br /><br /> web page2

 

[oldboat1]

Re: How to determine transom strength?

One hint for a likely maximum hp is sometimes the age of the boat. Unfortunately, I believe that OMC came out with the Fat 50 in '59 -- which is probably (but not necessarily) too heavy for your boat. Chances are, the 35hp is what the boatbuilder had in mind.

 

[crab bait]

Re: How to determine transom strength?

that coast gaurd booklet is the only way to go.. gives you a formula to follow..<br /><br />one major factor is tiller vs. steering wheel... same boat,, way different hp rating...

 

[dpropson]

Re: How to determine transom strength?

As always, thanks. It looks like the old tub will take a 40 hp. I'll go with a 35 hp, to be safe. <br /><br />Yes, I'd be fishing that Fat 50 off the bottom of the lake.

 

[11 footer]

Re: How to determine transom strength?

To ancer your first qustion, Weight does NOT mess up the transom HP does. This is what I have been told my whole life and I am sure it is right.<br /><br />11

 

[oldboat1]

Re: How to determine transom strength?

The 40 would probably be no different than the 35 in terms of weight and torque -- worth pointing that out because the 40 hp models from the '60s seem to be more readily available for period restorations (just seems that way to me). <br /><br />nice project -- Good hunting.

 

[rickdb1boat]

Re: How to determine transom strength?

Wonder why they make "Transom Savers" ????? Not much HP affect when you're trailering!

 

[dpropson]

Re: How to determine transom strength?

I believe you are right, Oldboat. Rick makes a good point also. Take a 150 pound motor and a 10" pothole and the engineer in me says bad things will happen.