materials used for keel bolt washers

[chrisbeale]

hi im new to this forum i am currently doing a college project studying engineering.

i have been set an assignment to study what 4 or 5 materials will be most suited to make a keel bolt washer and then pick the best one.

after browsing the net i now know that the washer is not for sealing it is for spreading the load and a sealent will be used for keeping it watertight.

i have searched many sites and am none the wiser in which material to use. i have found a galvanic table but to be honest it really does mean nothing to me as im not marine based.

information that you may require is this keel bolt will be made out of stainless or mild steel.

any help given is much appreciated thanks very much

[alan white]

The answer is mastistall, which any sailer could tell you is a material that's compatible with all marine metals. It is strong, stiff, and light (weight being important on a boat), and I do believe there are five grades available from low aspect to high aspect.

Good luck with your project!

Alan

[alan white]

Just kidding. I must be getting old because the prospect of leading you on haunted me while I mowed the grass.
I do think, however, that you ought to research the problem by teaching yourself about metals, salts, nobility, atomic weight, etc..
Surely you were handed a manual on materials. Otherwise, it's all available online under something like metallurgical properties, electrolytes, etc. (not keel bolt washers).

Best of luck,

Alan

[wet feet]

Who would selelct a mild steel keelbolt?The overwhelming majority of production boats today seem to use stainless steel.A washer made from the same alloy as the bolt would not have galvanic issues.
If,as may be the case,the boat is wooden and the bolt is to hold parts of the structure together rather than attaching the ballast the best choice is likely to be bronze.
Who gets the marks for doing the project? ;-)

[alan white]

Originally Posted by wet feet

Who would selelct a mild steel keelbolt?The overwhelming majority of production boats today seem to use stainless steel.A washer made from the same alloy as the bolt would not have galvanic issues.
If,as may be the case,the boat is wooden and the bolt is to hold parts of the structure together rather than attaching the ballast the best choice is likely to be bronze.
Who gets the marks for doing the project? ;-)

Not us certainly! No, we'd be lucky to be invited to the graduation ceremonies as ushers, as usual. Then one day we see a yacht out in the water suddenly rising two feet vertically and we know that the proper mild steel washer was used to attach a mild steel keelbolt, and both corroded at exactly the same rate of completely in one season.
If life was like a movie, an ambitious but spoiled lad would show up at our door to offer cash to be tutored in boat design but we would say, no, no money, move that pile of manure over there! Then they would grudgingly agree because we know everything, and over the course of the Summer they would begin to have self-respect for the first time in their sorry lives and come to love us as a father they never had because their mother was continually getting divorced and we would realize how deprived the poor kid really was, money and all.
Later, at their graduation ceremony with top honors, they might see us over the fence, just getting a glimpse, to know we had made things right and saved the day.
But nooooo! We are instead googled and then as quickly forgotten.

A.