Why Carriage bolts?

Dave Diefenderfer

Dave Diefenderfer

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Why are carriage bolts used to mount the motormount, ice runners/keelsons, and keel on a sneakbox? My experience with carriage bolts, is that they can not be tightened or removed after a few years. I know they look nicer with the smooth rounded finish, expecially on the motormount, but am thinking of just using hex head bolts and counter boring so they end up flush. I may look for some snap on covers for the motormount, but on the keelsons and keel, I am thinking to just fill flush with 4200 and then cover with the rub rail like John Bourbon did. Is there some real advantage to carriage bolts that I can't see?

Thanks, Dave
 
Dave,

When I built my broadbill sneakbox the plans called for bronze screws (or nails). I used either bronze or SS screws. My keelsons/keel were installed with thickened epoxy and bronze screws. On top of those I installed 1/8" alum rub rail bedded in 5200 and SS screws. The only place I could see using a carriage bolt for would be to mount the motor to the motor mount.

Ryan
 
In my case, I will be through bolting the keelsons, keel and motormount. At least in the case of the keelsons/ice runners, I consider them wearout items and anticipated replacement some day.... so I will not epoxy them on. I'll bed them full length with 4200, unless someone has a better idea....

Dave
 
Come to think of it, I may not have used screws on the keel/keelson's and may have just used thickened epoxy. I'll have to look back at some of the construction pics.
 
Dave,

I'm with you: no reason to use carriage bolts.

Brass or stainless screws w/ thickened epoxy for the keelsons; hex head bolts for the motor mount.

Rick
 
Dont know about keelsons & keels, but as far as mounting the motor, hex heads are the better option.
Use large washers on both (head and nut) sides.
In staight up fresh water you can probably get away with galvanized, go near any salt & you might better use stainless.
 
My plan is 3/8ths SS with fender washers. The current transom is ~2" thick. The piece of Mahogany I have for the motormount is 2" thick, but I will counterbore 1/2 inch the diameter of the fender washers to make the bolt flush on the outside. I plan to add another 1" thick Azek (plastic deacking) backing board inside the transom. 4 - 3/8ths" 6" long bolts should hold the 15hp Johnson? Dave
 
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Hi Dave. Four 3/8" thick bolts ought to be fine for holding the motor on. On that 28hp Evindrude I had, it was held on with a pair of 5/16" bolts plus the motor clamps and God knows we gave it ample oppurtunity to fall off and it never did.

John
 
well the 4 - 3/8ths bolts are to bolt the mahogany to the transom. I was going to use the motor clamps to mount the motor on the mahogany. I think I will mount a ring close to the motor and a short chain as well just so it can't fall too far from the boat ;)
 
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