Keel Bolt Torque

GordMay · #1 (**permalink**) 05-05-2003

C&C Specifies 250 Ft/Lbs torque for 3/4" Keel Bolt c/w 1-1/8" Nut.
Does this assume boat on the hard, sitting on keel?
Would the required torque be different for a boat afloat?
Tks,
Gord

DuaneIsing · #2 (**permalink**) 05-05-2003

Gord,

Here is my opinion on your keel bolt torque question:

Whenever threaded fasteners are used to join components, the designer is trying to achieve a desired clamping force by putting the bolt (screw, etc.) in tension. Since measuring the tensile force in the bolt is difficult to do, engineers specify torque values. However, the amount of tensile force in the bolt for a given torque value varies greatly depending upon the condition/geometry/material of the threads, their cleanliness, and degree of lubrication.

To your question, if all the above factors were equal, it should not matter whether the boat is on the hard or in the water. The resultant clamping force should be the same for the same torque value. To use a different value for the torque would imply that you need a different clamping force under those two conditions and I don''t see that as logical.

Hopefully folks with real boat experience will agree.

Duane

lecomte38 · #3 (**permalink**) 05-07-2003

TIGHT. as tight as you can make them with 1/2" drive sockets and a breaker bar.