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What size of tubeing should I use

C

CumminsPower

Member
I'm building a new motor stand and cage for my boat. I want to use square tube. What size of tubing should I use to hold my motor and how thick should it be? I'm going to mount a DD Chev 350 on it.
 
Mild steel is the least expensive. Chromoly is more expensive but the same material that engine mounts are made of in aircraft.

I like a good strong engine stand. I want that engine and prop to stay right back there where they're supposed to be, no matter how rough things get. Either of the above will work in 1" if you take care to see that there is good triangulation, and that the welds have full penetration.

I've seen stands built with as little as 1/2" tube, but to be honest I really don't like being around a boat that has an engine stand that skinny.

olf
 
What gage of one inch would you suggest to use. Good welds are no problem I'm going use a tig to weld it up. I also been looking at a lot of stands on the Internet to get a good design. I also want the motor and prop to stay put. I don't want it to try and pass me.
 
There are several builders on here that are much better qualified than to answer that than me.
C.Chardt (Dakota Airboats) or Faron Floyd (airboatcaptain2) will be more than willing to help you.

Best of luck with your project.

olf
 
I'm a bit tied up until Monday but I have a good design engine stand that is super strong. I'll dig it up for ya, in .jpg format or I'll post it here. Been proven over LOTS and LOTS of years.

I prefer to stick weld engine stands. I recommend thin wall square tubing. Strong enough but still light enough it doesn't become a weight factor.

Strength is in the design not the material. I have also built some of these for folks on a budget out of 3/4" EMT and brazed them together. The stands lasted longer than the boats. Im NOT recommending this though.

Scotty
 
Ok, I found it easier than I thought. Plug in your own dimensions to fit your boat and engine combo. NEVER, EVER, EVER make any kind of connection between the front section and the rear section. To do so will guarantee cracks and defeat the transfer of stresses to the boat.

Hope it helps.

Engine_Stand.JPG


Scotty
 
Most of the boats I've gotten had 14 or 16 Gauge mild steel square tubing. I would use 14 gauge for the motor stand myself for any car motor. 11 gauge would be just too heavy in my opinion.

I've never seen square 4130 chromium-molybdenum alloy steel. Tig welded mild steel should work fine.
 
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