two marine grade bolts... £96.08

dylan winter

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went on a bit of a spree today

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dylan winter

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only mine will be made of wood.

I did ask the local yard to do the job and they said not before November.   I am lanning to head west this summer so the ability to take the ground will be good.

F

 

dylan winter

Super Anarchist
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they are a retty good comny. I am sure they would have picked it up.

Man I hate drilling holes in the boat - although these are well above the waterline.

D

 

Fah Kiew Tu

Curmudgeon, First Rank
10,130
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Tasmania, Australia
I'm having a *REALLY* hard time thinking you need M30 bolts for anything on that boat. You could pick the entire boat up using a single M16 bolt.

So yes they're expensive. Do some lateral thinking on what you're trying to achieve and if there are cheaper ways to do it. I'll bet there are.

FKT

 

dylan winter

Super Anarchist
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I'm having a *REALLY* hard time thinking you need M30 bolts for anything on that boat. You could pick the entire boat up using a single M16 bolt.

So yes they're expensive. Do some lateral thinking on what you're trying to achieve and if there are cheaper ways to do it. I'll bet there are.

FKT
I spoke to some of the old blokes with trad fishing boats

They said that the diameter helps to spread the load to the surrounding timbers

They suggested the M30s - although they generally used mild steel which they said would outlive them as they are only in place for a few weeks a year when the smacks are ashore.

The bolt goes through both parts of the raised gunwhale. So I am bolting some 25mm marine ply pads to the fibreglass to spread the load to the surrounding GRP.

One of them said that I should have the legs a couple of inches shorter than the keel so that the boat heels slightly as she takes ther ground. 

I will nearly always be going down onto shingle or hard standing so I am not sure if I should do that.

D

D

 

Fah Kiew Tu

Curmudgeon, First Rank
10,130
3,276
Tasmania, Australia
I spoke to some of the old blokes with trad fishing boats

They said that the diameter helps to spread the load to the surrounding timbers

They suggested the M30s - although they generally used mild steel which they said would outlive them as they are only in place for a few weeks a year when the smacks are ashore.

The bolt goes through both parts of the raised gunwhale. So I am bolting some 25mm marine ply pads to the fibreglass to spread the load to the surrounding GRP.

One of them said that I should have the legs a couple of inches shorter than the keel so that the boat heels slightly as she takes ther ground. 

I will nearly always be going down onto shingle or hard standing so I am not sure if I should do that.
I thought it might be something like that.

Look, the diameter for bearing area makes total sense but there are much cheaper ways to get there. Either a short piece of 316 pipe - 20NB is ~26mm OD, 25NB is ~32mmOD from memory - with a M12 to M16 bolt through the centre, or a M12/M16 bolt with a bushing on the outside of it and a couple of big fender type washers.

If you were closer I'd make them for you for free as long as I had a dimensioned sketch to work from. God knows I've enough scrap pieces of pipe etc lying about the place.

FKT

 

slug zitski

Super Anarchist
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worldwide
I spoke to some of the old blokes with trad fishing boats

They said that the diameter helps to spread the load to the surrounding timbers

They suggested the M30s - although they generally used mild steel which they said would outlive them as they are only in place for a few weeks a year when the smacks are ashore.

The bolt goes through both parts of the raised gunwhale. So I am bolting some 25mm marine ply pads to the fibreglass to spread the load to the surrounding GRP.

One of them said that I should have the legs a couple of inches shorter than the keel so that the boat heels slightly as she takes ther ground. 

I will nearly always be going down onto shingle or hard standing so I am not sure if I should do that.

D

D
Mild steel is superior 

stainless is prone to galling and corrosion due to oxygen depletion 

unfortunately mild steel Needs  to be painted to prevent surface corrosion 

 

Fah Kiew Tu

Curmudgeon, First Rank
10,130
3,276
Tasmania, Australia
Mild steel is superior 

stainless is prone to galling and corrosion due to oxygen depletion 

unfortunately mild steel Needs  to be painted to prevent surface corrosion 
Rubbish, you clearly haven't read the intended use-case.

These things are for intermittent use in an above WL situation. Oxygen depletion isn't any consideration at all.

Yeah I could easily make them & post them but I think Dylan has already ordered them so - bit late.

Besides I don't do polished gee-gaws, that's definitely a SEP. Machining & welding, sure, shiny polishing, no. So generally I don't do work for people who want shiny things which eliminates a lot of the 'yachty' market.

I've thought about making legs for my boat but it's a long way down the project list ATM.

FKT

 

Panoramix

Super Anarchist
I spoke to some of the old blokes with trad fishing boats

They said that the diameter helps to spread the load to the surrounding timbers

They suggested the M30s - although they generally used mild steel which they said would outlive them as they are only in place for a few weeks a year when the smacks are ashore.

The bolt goes through both parts of the raised gunwhale. So I am bolting some 25mm marine ply pads to the fibreglass to spread the load to the surrounding GRP.

One of them said that I should have the legs a couple of inches shorter than the keel so that the boat heels slightly as she takes ther ground. 

I will nearly always be going down onto shingle or hard standing so I am not sure if I should do that.

D

D
I think mild steel is better. Stainless is not very ductile and you need ductility here so that if you hit something you bend the bolt rather than break it. As @Fah Kiew Tu said, raw strength is not an issue here.

Here in Brittany, legs are also shorter. The thinking behind this is that the legs are there to stop the boat falling on its side not to bear its weight. On uneven ground you are less likely to end up with all the boat weight on the legs if they are shorter, especially with a long keel boat as the keel is likely to "find" a couple of high spots.

 
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