Mast step bolts very rusty - problem?

Captain Crisp

Captain Crisp

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Hi, the bolts that hold my mast step in place are pretty rusty...
Should I try and replace them?
Is it urgent?
I'm unsure how much pressure they're likely to be under.
Any thoughts?
Many thanks,
Crispin

c1_20240224_15183142.jpeg
 
Probably OK they won't be under much stress. But imagine you are offshore with a rising breeze and the thought of those bolts pops onto your head. New bolts will give peace of mind.
 
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Mast step bolts are there as guide to position ..... to position the mast mount.

The forces on them are across the bolt horizontally - not vertical. Think of the mast ... it stands there steadied by masthead stays .. and then just above half height by further stays that control the mid section. When boat heels under sails - the mast wants to 'fall over' but is held by the shrouds / stays ... with the mast heel pressed into and held by the mast fitting on deck. Those bolts would have to be seriously corroded to actually give way .....

But like everything - its always better to have new and peace of mind.
 
They look fine. A wire brush and some paint ,will probably look nearly new again.
People have posted pics of keel bolt nuts that look like they are well beyond salvation but a wire brush, some paint and they look really good.
 
Captain Crisp said:
Certainly is!
Click to expand...
New boat for you, if so how exciting. those bolts are difficult to remove so id just remove the nuts and replace them at your leisure. A few of us here that love Twisters, especially a good composite one. For what ever reason they are just so nice to work on and I do think they are built really well.

Lucky you
Steveeasy
 
steveeasy said:
New boat for you, if so how exciting. those bolts are difficult to remove so id just remove the nuts and replace them at your leisure. A few of us here that love Twisters, especially a good composite one. For what ever reason they are just so nice to work on and I do think they are built really well.

Lucky you
Steveeasy
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You sound as if you miss yours.

You should buy another.

As it happens..... 😉
 
I'd want to take at least one out. These kinds of bolts are almost always in better condition on the surface and could well be down to a few mm of good metal inside the deck where they'll have been silently rusting out of sight. A couple of recent dismastings were down to corrosion of bolts on the section inside the deck (chainplates rather than mast step) so it's worth being sure.
How seriously I'd take it would be down to the size of mast - on my old 20 footer it wouldn't have done a lot of damage on the way down, but on a 40 footer it could well destroy the boat and occupants.
 
DanTribe said:
Probably OK they won't be under much stress.
Click to expand...

When you are under sail the boat is being dragged along forwards and sideways through the water by the mast foot, along with the chainplates and the main and genoa tracks.

When you are not under the sail the mast foot and other things mentioned (save the genoa track) is what stops the mast going over the side as the boat rolls and pitches.

So the mast foot is under a lot of (as Refueller mentions) horizontal stresses - think of it as a strange shaped towing eye - and is held there by a combination of friction with the top of the cabin, and the bolts.

I agree that the bolts themselves won't usually be under excessive stress compared to their number and original thickness, but you wouldn't want to be without something similarly substantial.

I suspect that rust seen in the photo is just surface rust, but drawing the bolts to check they're not waisted would give peace of mind.
 
Poignard said:
You sound as if you miss yours.

You should buy another.

As it happens
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Dont do it. Do I miss mine ?. id say I am fully contented having had so much fun restoring it and indeed some of my sailing and cruises. such fantastic memories with good friends. ill never replicate those experiences again. The boats are well made and bullet proof. I enjoyed sharing stuff with all the owners. I dont miss nasty premadonas.
Funny you get more leaks in a Contessa than a composite Twister. the Hulls are thin and not made as well. I am really enjoying my Contessa and the work I am doing to her. New challenges and new experiences.

Happy Days.
Steveeasy
 
I see you've used stainless eye bolts which is a definite nono when in conjunction with a galvanized fitting. The stainless is going to eat the galvanizing away. You should fit proper hot dipped gavanized bolts. Sorry...
 
Antonio Silva said:
I see you've used stainless eye bolts which is a definite nono when in conjunction with a galvanized fitting. The stainless is going to eat the galvanizing away. You should fit proper hot dipped gavanized bolts. Sorry...
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Don't be sorry, your point is perfectly valid, and one that I gave some thought to.

To guard against that happening, there are plastic washers between the galvanised mast step and the eye nuts, and the bolts were coated in Duralac where they pass through the mast step.

After shotblasting and galvanising, the new mast step was painted with International Etch Primer > International Primocon > International 2-part Topcoat.

This work was carried out in 1998, and seems to have survived the intervening 26 years between then and today pretty well.
 
Poignard said:
Don't be sorry, your point is perfectly valid, and one that I gave some thought to.

To guard against that happening, there are plastic washers between the galvanised mast step and the eye nuts, and the bolts were coated in Duralac where they pass through the mast step.

After shotblasting and galvanising, the new mast step was painted with International Etch Primer > International Primocon > International 2-part Topcoat.

This work was carried out in 1998, and seems to have survived the intervening 26 years between then and today pretty well.
Click to expand...

Investigation - dedication - preparation - execution. ;)
 
Antonio Silva said:
I see you've used stainless eye bolts which is a definite nono when in conjunction with a galvanized fitting. The stainless is going to eat the galvanizing away. You should fit proper hot dipped gavanized bolts. Sorry...
Click to expand...

Using galvanized connected to stainless steel when submerged in sea water will cause the galvanizing to corrode away but not so much on deck or inside the boat.

I have a steel boat with both stainless steel welded and bolted to the steel structure and stainless steel fittings underwater

The insterial structure has been galvanized and bolts with stainless steel bolts / nuts and show no corrosion after 15 years being fitted

Bow Vee bunk framing
https://flic.kr/p/WVhxrm

Before galvanizing
https://flic.kr/p/VKkNaD

Mast support galvanized steel RHS
https://flic.kr/p/WVhxGw

Side bunk support frame
https://flic.kr/p/WVhxc3

Gally support frame before galvanizing
https://flic.kr/p/VKkLLM

Saloon seating frame before galvanizing
https://www.flickr.com/photos/152956403@N05/35917421002/
Bow chain locker in background before galvanizing
 
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