If your screwing above the waterline, then you can use Stainless deck screws like you will find at HD. But below or in wet wood, use bronze. The stainless screws are decent and stronger than the bronze.
On my old 1970 woodie, a lot of brass like screws were above the waterline, but all the plank screws were Everdur bronze. And those brass like screws tended to corrode, get weak and were not reusable as the screw shank would twist off in the wood. When you looked at the screw threads you could see necking, where the metal had corroded.
I always wondered if they were brass or bronze. Likely just brass.
So all over the boat it was a mix perhaps of some brass screws, but most were bronze.
All the wood screws below the waterline were 'Everdure Bronze' And I was able to reuse many. On those which decayed and were not usable, they would tend to waste away, but still retained a lot of strength. I still used about 4000 new bronze screws for the reframing and planks. I was able to reuse all the planks. But much of the framing was replaced. Many of the old screw holes were rotten and would not hold screws. After plugging a few, I decided it was not worth trying to work with those frames.
You know Titanium is a very common element. Maybe someday titanium fasteners will be cheap
. They wont corrode at all. Too bad titanium is so pricey, it would be a very good metal to use in so many things.
I have a lot of screws left over and I would like to melt them into something useful. Which someday I might try to bronze cast something.
A plank screw on a wood boat sure it holds the planks tight to the frame, but the screws are also loaded sideways, so really you need smooth shanks, not screws with threads all the way to the head
or with necked screws. The screws should be cut thread not rolled threads. And the area below the screw head residing in the plank should fill the hole. You can do all the right things and and all your doing is delaying the inevitable screw wasting. Water
will get at the fastener regardless if there are wood plugs on the planks. What I did was use PL Premium poly Construction adhesive
for plugs and also for seams. Worked out very well.
And coated the hull
with Sanitred Permaflex inside and outside.
And, when I replaced the frames I used treated wood.
On my boat there is a 1 inch mahogany bottom plank, a 1.25 inch by 2 inch frame rib
, then a large beefy 2 inch wide oak floor joist extends across the entire boat and these are spaced every 7 inches. These oak floors are of various height (about 8 to 12 inches at the center and taper to the ends) and form the inner sole floor of the boat for the bilge
area. None of the floors or planks were bad, it was mostly the small frames and these were easily renewed with all the planks off the bottom.
Doing what I did has made a watertight solid hull
, more like a cold molded solid wood construction.