• Hi all and welcome to TheWoodHaven2 brought into the 21st Century, kicking and screaming! We all have Alasdair to thank for the vast bulk of the heavy lifting to get us here, no more so than me because he's taken away a huge burden of responsibility from my shoulders and brought us to this new shiny home, with all your previous content (hopefully) still intact! Please peruse and feed back. There is still plenty to do, like changing the colour scheme, adding the banner graphic, tweaking the odd setting here and there so I have added a new thread in the 'Technical Issues, Bugs and Feature Requests' forum for you to add any issues you find, any missing settings or just anything you'd like to see added/removed from the feature set that Xenforo offers. We will get to everything over the coming weeks so please be patient, but add anything at all to the thread I mention above and we promise to get to them over the next few days/weeks/months. In the meantime, please enjoy!

Marine fastenings

D

Don McDermott

New Shoots
Joined
Nov 16, 2024
Messages
114
Reaction score
147
Name
Don McDermott
LOCATION
Bourne End
Hello everyone,

As many of you know, I'm building the 48-foot sailing wherry Lady Garnet. I'm getting very close to laying the keel, and I urgently need to decide what I'm going to do for fastenings. There seem to be quite a few options, and I hear various pros and cons, so if anyone could offer advice, it would be appreciated. The options, as I see them, are as follows:

1. Galvanised iron - this would be the most traditional way, but not sure if this would be a good idea, and unsure how easy it would be to find galvanised iron these days
2. Galvanised steel - Steward in the Boatbuilding Manual advises against galvanised steel because modern stuff can be hit and miss compared to what they used to make. However that book was written in, I think, the 80s, so perhaps galvanised steel has improved again?
3. Stainless steel -- 316/A4 obviously, as that is marine grade. I've heard great things about stainless online, but also some negatives about using even marine grade for underwater fastenings.
4. Silicon bronze -- really good stuff, I know, but it's rather expensive...
5. Copper -- the wherry is clinker-planked, so I could use copper for nailing the plank overlaps, but obviously copper would not be suitable for the keel bolts or for fastening the planks to the frames

I could also use a combination but galvanic corrosion comes into play. My understanding is that galvanised steel cannot be used with stainless steel or copper, but stainless and copper are okay together, and I believe silicon bronze is also okay with copper and stainless. I am not sure about galvanised iron.

Anyway, once again, thanks for any help, it's greatly appreciated!

Don
 
What type of fastenings ? As for galvanic corrosion you just need to look at the scale, with the wrong metals in contact you create two electrodes that in seawater will produce a voltage that results in electrolysis. To prevent this you need to keep both sides apart using something like nylon bushings or fully connected so both are at the same potential.
 
Spectric said:
What type of fastenings ? As for galvanic corrosion you just need to look at the scale, with the wrong metals in contact you create two electrodes that in seawater will produce a voltage that results in electrolysis. To prevent this you need to keep both sides apart using something like nylon bushings or fully connected so both are at the same potential.
Click to expand...

Bolts for the keel, nails for the planking and frames or possibly nuts and bolts for them as well.
 
Bronze for the keel bolts etc, and copper for the rivets and roves. Don't even think about galvanised steel or iron for anything at all. You're building the boat of oak, and galvanising will only slow down the oxidation by a year or two. Knock a galvinised nail an inch or two into a piece of green oak now, and pull it out in a couple of months time. You wouldn't ask the question if you'd ever seen the result.
 
Spot on ^. I used 13mm heavy duty galvanised coach bolts to hang our large gates, set in large oak posts, with drilled holes and bolts coated with petroleum jelly. They turned basically to cheese within 5 years. Even marine stainless will get rust spots. Back in the day I used to do yacht deliveries sometimes and have often seen marine stainless beginning to show rust streaks with the constant attack of seawater.
 
Thanks for the replies so far, everyone. So galvanised is definitely out, and I'm thinking less highly of stainless steel. Silicon bronze keel bolts sound like a good plan, I'd probably just make them myself from a round SB bar and cutting threads both ends for the nuts, which is what I did for the keel bolts for the dinghy I made. I'm almost certainly going to use copper nails/roves for the plank overlaps, 3 inch gauge 8s should do it. The main question then is what to do for the plank-to-frame fastenings. Again, a few options:

1. Silicon bronze screws
2. Silicon bronze bolts, which would be more expensive than the screws but more secure?
3. Copper nails/roves, but they would need to be about 7 inches long, maybe 5/16 thick (no idea what gauge that is, I don't think they sell them that size). So I would probably have to buy a copper bar and make the nails myself using a hydraulic press rigged up to press the heads. Not something I'm familiar with but I'm always keen to learn new things! Not sure what I would do for the roves though, can't get them either and seems they would be more complicated to make.
 
Don McDermott said:
......The main question then is what to do for the plank-to-frame fastenings. Again, a few options:

1. Silicon bronze screws
2. Silicon bronze bolts, which would be more expensive than the screws but more secure?
3. Copper nails/roves, but they would need to be about 7 inches long, maybe 5/16 thick (no idea what gauge that is, I don't think they sell them that size). So I would probably have to buy a copper bar and make the nails myself using a hydraulic press rigged up to press the heads. Not something I'm familiar with but I'm always keen to learn new things! Not sure what I would do for the roves though, can't get them either and seems they would be more complicated to make.
Click to expand...

Whenever I have a design issue to sort out, I go and look at what they used to do in the old days, and ask myself what they would do if they had the options we have. What was the plank/ frame fixing that was used for typical Norfolk wherries? If it was made of iron, then what would they have done if they had bronze as an option? So, if I was you I'd be looking inside one or two wherries.
 
Mike G said:
Whenever I have a design issue to sort out, I go and look at what they used to do in the old days, and ask myself what they would do if they had the options we have. What was the plank/ frame fixing that was used for typical Norfolk wherries? If it was made of iron, then what would they have done if they had bronze as an option? So, if I was you I'd be looking inside one or two wherries.
Click to expand...
They used boat nails in the old days, probably galvanised iron. The wherry Maud, when she was restored in the 70s/80s, used galvanised mild steel bolts, which seems surprising, but that is what they told me it was. I am not sure what the wherry Albion uses, I'm waiting to hear from them, otherwise I am sailing on her in a few weeks and will have a look.
 
You must log in or register to reply here.
Back
Top