Folkboat Fit-out

[woolleyhatter]

Hey guys
Do you think that i will have a prob if i fit out using nothing but Stainless (A2) steel.
fed up with trying to remove old brass screws that have corroded etc. Apart from the copper roves the galvanic corrosion will be kept at a min, is that right??
Any advice as usual is appreciated.

[pcford]

Hey guys
Do you think that i will have a prob if i fit out using nothing but Stainless (A2) steel.
fed up with trying to remove old brass screws that have corroded etc. Apart from the copper roves the galvanic corrosion will be kept at a min, is that right??


No.

Stainless is not to be used below the waterline for all but small dry moored boats.

Use bronze.

[Thorne]

Brass?? Someone used brass fasteners on your boat? Do you mean silicon bronze?

[Yeadon]

He probably meant bronze.

[chainyank]

He may be right. Over here alot more brass screws are used than bronze. Its a shame really, because they are so hard to get out, the are just so soft.... So I don't doubt a folkboat would have some brass screws. My 2 "öre"

[Flying Orca]

No.

Stainless is not to be used below the waterline for all but small dry moored boats.

Use bronze.

Would you expand on that? The designer of the boat I'm building specified SS fasteners in the keel and stem. They're under epoxy and paint, but still, your post intrigues (let's not say "worries") me.

[Ryden]

Hey guys
Do you think that i will have a prob if i fit out using nothing but Stainless (A2) steel.
fed up with trying to remove old brass screws that have corroded etc. Apart from the copper roves the galvanic corrosion will be kept at a min, is that right??
Any advice as usual is appreciated.

Bronze is preferable, but if you go SS, then use A4. A2 will not last in saltwater.

[dennisbur]

Stainless is not recommended for keel bolts. Lead and stainless are galvanic when used together. At least according to David Gerr in "Elements of Boat Strength".

[Flying Orca]

Stainless is not recommended for keel bolts. Lead and stainless are galvanic when used together. At least according to David Gerr in "Elements of Boat Strength".

Ah. OK, well, there's no lead in my boat.

[ahp]

BRASS fasteners dezincify in time when exposed to salt water and become brittle. Brass consists of zinc rich crystals and copper rich crystals and they have a difference of electromotive potential. In time the zinc rich corrode away. It doesn't seem to happen with massive brass hardware.

[RFNK]

Even 316 stainless is susceptible to crevice corrosion in saltwater, especially in warmer water. Stainless fasteners through wet timber underwater are particularly susceptible. When I restored our Folkboat, several of the lower 316 stainless bolts holding the stainless chainplates were badly corroded yet looked perfect from the outside and inside. Only when I withdrew them, could the severe corrosion where the bolts passed through the timber (coachwood ply) be seen. Some of them had turned to powder. Our keelbolts are bronze and I use bronze fasteners wherever possible underwater. However, I replaced the chainplate fasteners with 316 stainless bolts set in epoxy `plugs'. I used these as I couldn't easily find silicon bronze fasteners to suit and I wasn't sure of the wisdom of using them with the 316 chainplates. Our Folkboat is set up for coastal cruising so we have two chainplates on each side. I'll draw a couple of fasteners out every few years to check for corrosion. If there's any sign of it, I'll replace the whole lot again. Rick

[pcford]

Even 316 stainless is susceptible to crevice corrosion in saltwater, especially in warmer water. Stainless fasteners through wet timber underwater are particularly susceptible. When I restored our Folkboat, several of the lower 316 stainless bolts holding the stainless chainplates were badly corroded yet looked perfect from the outside and inside. Only when I withdrew them, could the severe corrosion where the bolts passed through the timber (coachwood ply) be seen. Some of them had turned to powder. Our keelbolts are bronze and I use bronze fasteners wherever possible underwater. However, I replaced the chainplate fasteners with 316 stainless bolts set in epoxy `plugs'. I used these as I couldn't easily find silicon bronze fasteners to suit and I wasn't sure of the wisdom of using them with the 316 chainplates. Our Folkboat is set up for coastal cruising so we have two chainplates on each side. I'll draw a couple of fasteners out every few years to check for corrosion. If there's any sign of it, I'll replace the whole lot again. Rick

I think you answered the poster's questions perfectly.

And if I may....I would be very dubious about a designer or builder who specifies stainless in this kind of application.

Like the guy said....if he didn't know about that one...what else didn't he know?

[Flying Orca]

Well, to be fair, the only place he specifies SS is in sealed interior use (epoxy filled and plugged). The hull is glassed, so I would expect it to remain reasonably dry. Bronze ring-nails in the planking, again glassed in, and a steel centreplate are the other metals under the waterline.

[pcford]

Well, to be fair, the only place he specifies SS is in sealed interior use (epoxy filled and plugged). The hull is glassed, so I would expect it to remain reasonably dry. Bronze ring-nails in the planking, again glassed in, and a steel centreplate are the other metals under the waterline.

MMMMaybe. Would not bet my life on it.

[Flying Orca]

Will the fact that it's going to be used in cold freshwater help?

[woolleyhatter]

Thanks again for all the help/suggestions. It seems as though brass is not to be used, but just to re-iterate it's just for fitting out, so obviously above the waterline, and my FB has a steel/iron keel (albeit rusty!).
The old screws were def brass, but i'll see what the cost of silicone to brass to ss (A4) is.
Thanks again