Which wood for Bilge Keel Sacrificial Strips??

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MrCramp

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I have sacrificial strips of wood on the bilge keels and the centre keel on my Swin Ranger. On the bilge keels they are about 5ft long and 1.5inch by 1inch and on the main keel about 14ft and 2inch by 1 inch.

Which wood should I use to replace them? Is whatever is used for post and rail fencing likely to be OK?

Also should I use stainless bolts or normal steel ones? The heads will be immersed in water most of the time.
 
Treated fence or railing timber is a bit unfair on the maritime environment, as it contains pesticides and fungicides. It's also very soft, usually made of sitka or similar pine/larch/spruce. Not recommended as sacrificial strip.

You need a hardwood, so oak, preferably green if you can get it.
 
Rail fencing timber is too soft.
Go to a local timer yard looking for off cuts and get either some Iroko or better oak, it will last you out, will cost extra but do the job once!
Also suggest you consider fitting thicker wood to both the sizes you give as it is not all that thick for wear strips.

Or try a local shipyard and ask do they have any old wooden piles these will last even longer.
Do not use standard bolts/nuts, stainless is more expensive but a one off job, normal HT (high tensile) nuts and bolts steel will rust and you will have a great time replacing them.
 
I used green oak on my Prout, and they were still doing fine after 7 years to my amazament. Bonded them on by cutting grooves in the oak with a circular saw and bonding with West epoxy to the bottom of the grp keels. Put a strip of woven roving over the join at the leading edge of the keel. They stayed stuck on no problems. And that was in an area and on a mooring which dried every tide.

One of my better projects tbh
 
No experience of sacrificial strips on bilge keels, but when I was gliding (way back) one of our 2-seaters (a T21) used an oak skid with a stainless steel sacrificial strip screwed to it to take the runway wear. Might be an idea for your bilge keels.
 
Iroko would be cheaper and more durable but you might want to bolt it to the keel rather than just glue it as it can be so oily the glue has a hard time sticking. But any dense oily hardwood will be fine. English elm is also traditionally used and has the strange property of being non-durable above water but very durable when saturated. If you use any stainless underwater it MUST be 316 not 304 which is architectural grade and rusts in sea water but you should really use bronze as all stainless can corrode underwater in wood (if wet with no oxegen present it rusts just like normal steel). Oak is prticularly a problem, having a high acid content it suffers badly from 'nail sickness' I have seen S/S burn a 2" diameter hole through a 3" thick stem when someone replaced the bronze eye bolt for the bowsprit with a 'modern' stainless one
 
If you can do so, avoid using stainless bolts in wood under water. They will be surrounded by wet wood but without free circulation and oxygen so they will corrode at a rate that will surprise you - as I discovered with the 316 bolts through the skegs of my cat. The epoxy gluing technique really did work well though it has to be said my keels were 10 ft long and as much as 4 inch wide in the middle.

If you have to use bolts, use the appropriate bronze
 
Thanks for all the replies. Off to the boat for a long weekend now.

I have 4 bolts through each bilge keel and 6 through the centre keel, so 14 needed. The holes are 10mm so I need to make sure they don't leak. The old bolts were steel and were a bit corroded, but not too bad.

I had extensive corrosion on the stainless 316 bolts fixing the bottom rudder support on my previous boat. I'll see how much bronze bolts are going to be, but I want to do the job so it will last 10+ years so I need to do it properly.
 
Keruin. Possibly spelt wrong! I took the advise of a boat builder who had tried just about every possible alternative. His advise was keruin. As used on flat bed lorries for the load area. Cheap to buy and very durable. Amazingly you can simply fit it with Sikaflex and no screws. I have had this on the keels of my Prout for a season ans still look like new. Even with grounding around on a shale bottom as she floated a few times there is no signs of movement or loss of adhesion.
 
Sounds like a MacWester or an Achilles? It all depends on how flat the bottom of your keels are. On my Prout they were pretty flat and with a good angle grinding I was able to properly bond the shoes. If your keels arent flat, then failing bronze bolts I would go for galvanised steel rather than stainless. My experience of stainelss below water in skegs morrors your own.
 
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