A marine gearbox is normally lighter then an automobile box a all there is, is forward and reverse.
-- John B.
A marine gearbox is normally lighter then an automobile box a all there is, is forward and reverse.
-- John B.
Since no one actually answered Karl's question I'll play what-if. For fun using your 3000 lbs and a beam simply supported at the ends with a span of
10', I used a load of 9000 lbs concentrated at the center (using the x3 factor for a live load to take into account when it bounces up and down as it comes off the mounts :-)). With 4" square tubing 0.5" wall the max deflection is 1" and the peak stress is 48 ksi which is getting right close to (or over) a typical yield strength for structural steel, so if you use square tubing it better be 5" and heavy wall, or bigger. There are two types of I beams, S and W, looking at S beams a 5x10 which is 5" tall and 10 lbs/ft (and the flanges are 3" wide) standing so it is 5" tall and 3" wide is a tad weaker, and the lightest 6" beam, S 6x12 is more than enough (assuming no additional safety factor and a yield strength of over 40 ksi), deflection .51" and max stress 37 ksi. In the W series the 5x16 is about as strong as the S 6x12. So any 6" I beam or a W 5x16 would just do it. Make sure you have the beam tall and narrow and clamp it so it can't twist and all fall down :-). I like the shareware program engineering power tools available at----- Regards, Carl Ijames
You guys are all forgetting about the tranny that comes out with the engine. Marine engines blocks are far larger allowing for raw water cooling. I think 3,000 is still a good guess.
Karl
Finally, someone with some _sense_...
-- ...in order that a man may be happy, it is necessary that he should not only be capable of his work, but a good judge of his work. -- John Ruskin
Thanks for the tool link, Carl.
But I still think 3000 pound guess is a bit high for a 600 pound motor.
Plonk
When he says "big block" I'm ASSuming he's talking a GM V8 Elephant -
396, 427, or 503 - or a Ford 460, or a big Mopar (413 etc) , all of which see a fair amount of Marine use.Fully loaded for marine use, the ENGINE will be under $1000 in all cases - the gearbox (straight or V Drive) will add a couple hundred. I'd say 1500 would be pretty safe for an "all in" weight
Karl, The engine block used in marine engines is the exact same one used in other applications. If it's a big V-8 then it's either something like a 460 Ford or a 454 or
502 Chevy. Mercruiser uses mostly GM products, Volvo/Penta uses Ford and GM if the engine is a gasser, The only real difference between the street engines and the marine engines are the camshafts and the exhaust manifolds. The cams are usually ones ground to give a flatter torque curve at a lower rpm than the street versions. The exhaust manifolds are cast so they can be water cooled. The rest of the parts can be interchanged easily. BTDT a lot. Until you get up into the BIG diesels most of the boat engines used are nothing more than heavy equipment engines. Cat/GM/Perkins/Cummins/Waukesha/Mitsubishi all have been used as well as some others. Nothing special about them.120lbs (12Lbs x 10') of steel could be difficult to set atop the posts safely without an engine hoist etc. The 8' rail for my temporary gantry crane extension is bad enough to maneuver overhead at 80 Lbs. I balance it on a second taller stepladder to allow one free hand to align it and insert the bolts.
Has anyone ever seen or used such a rig?
jsw
Thanks for the tool link, Carl.
But I still think 3000 pound guess is a bit high for a 600 pound motor. [/quote]
I'm not disagreeing at all, but at least now Karl knows that if it really is
3000 lbs then a 6" I beam is the bare minimum, and if it really is 1000 lbs he will have an extra factor of 3 safety margin. The rest is up to him (hey, us Carls have to stick together even if he does spell it funny :-)).----- Regards, Carl Ijames
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