Steel speds?

[ted655]

What type of steel is good for small boat construction? Low carbon right. Is there a common industry name or spec number? Is there a rule of thumb cost per pound that allows rough cost estimayion? Thanks.

[jehardiman]

What is it for and how cold do want to go? In the US, normal "ordinary strength" (OS or generic "A36") steel is generaly spec'ed American Bureau of Shipping (ABS) Grade A (ABS/A) or B (ABS/B) which goes down to 3/16" thickness, however this material cannot be used in certian structural components. For normal "world wide" applications where there will be a classification society inspection, I (when building in the US) would spec ABS high strength fine grain killed plate such as ABS/DH32 and ABS/EH32, or ABS/DH36 and ABS/EH36. These steel have significantly better impact properties and toughness.

Since I don't handle the cost side of the house, I can't say what the current price is, but just be warned that steel is spec'd by thickness or weight per square foot (i.e. 3/8" or 15.7# plate) but paid for by the ACTUAL WEIGHED poundage. It has been my experience that plate will generally come in 3-7% overweight depending on thickness which is the normal limit for "mill tolerance".

[ted655]

=="What is it for and how cold do want to go?"==
Well... a boat around 12-15 m. I live in southern USA and have no plans to ever see an iceburg. North New York state, The Erie canal in October, is as cold as I want to get.
Plate, angle, flat &Tbar. 1/2" for a narrow ballast kell, 3/8 & 1/4 below waterline, 3/16 for sides & bullwarks. That sort of steel.
Thanks for the clasifications, that helps.

[jehardiman]

I would spec ABS/EH32, OS steels only have good impact down to ~ 10F.