Mast Foot Screw Removal

[Skippy36]

Hi I need to remove the foot of the mast. The foot is held in by 8 stainless steel screws which are seized. I've tried WD40, no joy. The screw heads are in good condition and I don't want to damage them. If the screws are removed, with anyone's advice, what is likely to be involved in removing the foot? Is it just a case of gently whacking it with a wooden mallet?
Pic may help.
Boat & mast are 40ish years old and I doubt it's been removed before.

The reason for needing it off is;
1) The main halyard is 'stuck' part way up, but not too far I don't think - it was snapped - and I need to remove it.
2) some of the wheels at the foot of the mast are stuck and I need to loosen / replace them.

Thanks.

 

[rogerthebodger]

To be honest IMHO I don't think you will be able to remove all of those screws. If you do you would be one lucky SOB.

IMHO the only is to drill and hope you drill the bolts central.

Some people have tried heat on screws or freezing the bolts with differing degrees of success.

It looks like the screws have slotted heads so an impact driver may be the best tool. A normal straight screw driver will be no good

 

[pampas]

Been there, done that. I removed mine by "Painting" a drop or diesel the used a impact driver 1st clout not to hard to tighten then a hefty clout to undo, repeated several times before any sign of movement. use as lump hammer. best of luck.

 

[Magic Star]

A bit foolish idea, but who knows: welding stainless steel bolts to the screw's heads and try with a proper ratchet?

 

[Hypocacculus]

I've read about a trick that involves applying significant heat to the screw and applying beeswax which gets sucked in as the screw cools. No idea if it works though... I suggest a good search of motor restoration fora because steel screws stuck in lumps of aluminium are a fact of life for them.

Do be careful about whacking the mast with a hammer... aluminium cracks relatively easily.

 

[Skippy36]

Thanks all, will buy / borrow an impact driver. Don't think i'll drill as knowing my luck i'll need a new mast! I am an SOB but not a lucky one!
:ambivalence:

 

[Stemar]

I think your best chance is to dowse them with ACS50 or similar (WD40's a waste of time in my experience), leave them overnight then take the biggest screwdriver that'll fit the slot and give each screw a couple of good welts with a hammer before unscrewing. If that doesn't work, plan B would be the inpact screwdriver. It may help to give it a couple of thumps in the tightening direction before trying to undo. Plan C would be Mole grips, with an even chance of breaking the head of the screw off.

Thanks all, will buy / borrow an impact driver. Don't think i'll drill as knowing my luck i'll need a new mast! I am an SOB but not a lucky one!
:ambivalence:

Your worst case scenario would be losing a centimetre or so of mast length if you had to cut the holes off. Provided the rigging screws have enough slack, it's unlikely to be an issue.

 

[rob2]

Best of luck with getting the screws out, although it may well be that a few will have to be drilled out. I once failed to remove a mastfoot after getting the fasteners out, simply because the plug had expanded so tightly into the mast section that I couldn't shift it. Bear in mind that the screws are probably located halfway up the plug, so the depth of engagment is considerable. If it really must come out, the you may have to drill and tap into the base to fit a slide hammer to shock it out. Pouring kettles of boiling water over the mast should help at this point.

Another tack is to remove the sheave box and fish for the lost halyard with a wire coat hangar. Difficult and frustrating in the extreme, but it usually works eventually. I well remember reflecting sunlight down the mast from my watchglass for my mate to see what was going on down his end.

Rob.

 

[Skippy36]

Thanks Rob2, I'll have a go at your 2nd tack at the weekend. The fact that a couple of the wheels are seized is not great but I'm sure they must have been like it for years. Most important is to get the bit of halyard out, which I don't know how much is up there, as I need to run 3 new halyards down the mast and could do without any obstruction.

 

[Seajet]

Hi Skippy,

if you do have to use a hammer or impact driver - and you sound a handy sort of person - put a weight like a club hammer etc on the opposite side of the bit you're hitting - a la rivet dolly - to soak up the impact.

For threading new halliards I use a long whipping twine with a few M4 nuts on the end, sufficient weight but flexible enough to go around corners; needs a hooked bit of wire at the bottom.

As for mast sheaves, at the lower end I fitted double ball bearing sheaves with the line coming out between; this copes with any direction of pull and avoids abrasion from the upper edge of the mast slot.

Good luck !

Andy

 

[Skippy36]

Thanks Andy,
Great advice as usual.

 

[lw395]

Sometimes a screwdriver bit heated with a blowtorch is a good way of applying heat.
Any oil becomes penetrating oil at 300degC. 3 in 1 is as good as anything with a bit of thermal help.

 

[oldsaltoz]

I have had some success using a length of fencing wire down the mast, it means you can push and pull.

Good luck and fair winds.

 

[William_H]

As said I would be trying to get a new halyard mouse line down from the top. Or try from the bottom. A stiff wire might help. Sheaves that are stuck may be moved with a tight turn of old rope twisted to tighten on the sheave then try to turn the sheave. After suitable penetrating oil.
If all else fails including trying to move the screws. As said cut the mast a little above the ring of screw heads. Hopefully you cn then remove the mast foot (plug) with persuasion.
A carefully calibrated bashometer might help. Mostly a few cms of mast shortening will not cause too many problems. If so perhaps the mast base on the cabin top can be raised on a block. Good luck and I hope you get out there sailing soon. olewill

 

[penfold]

Repeated application of a decent penetrating oil like PlusGas, cyclicly heating the whole mast foot with a gentle flame or full power from a hot air gun, then cooling the screw heads with freon spray before going at it with the impact driver will maximise your chances of shifting the screws.

 

[vyv_cox]

Unfortunately your screws are probably made from a 300 series stainless steel. This material is not particularly strong and applying an impact driver to them will almost certainly shear the heads off if the threaded part is well corroded into the end casting. I suggest trying the methods that do not involve applying massive amounts of force, e.g. penetrating oils, heat, boiling water, etc before going the drastic route.

 

[simonfraser]

yep, been there, will be a total ******* to get them all out, without breaking them, buy a lottery ticket, more chance of success.

the suggestion of 'just' cutting a small section of your mast off and refitting the item is best imo.

 

[Daydream believer]

Cutting a bit off the mast must be a big no no
All the rigging might need renewing
If you can avoid taking the foot off go to a tool store & buy a set of 1 metre long cable pullers these are glass fibre rods approx 5 mm diam that screw together there are a couple of hooks supplied
Cost less than £20-00 for 10 metres
When you get them you will be amazed how handy they are
You can also get a set of 12 inch ones
Great for threading wires in a boat
As others have said remove the sheaves to get access
From the picture you have the mast on the ground so Seajets idea of using a line with nuts for weights will involve lifting one end up & waggling the top. Not likely to work

 

[lw395]

Getting the lines through can be done with any semi stiff wire or rod.
But that does not address the seized sheaves.
chopping a small amount off the mast section may be an option, maybe raise the mast step on a plinth to compensate at least partly.
I would agree there is a fair chance some of the screw heads will break off.
I would be prepared to drill the screws out. Take a small pillar drill to the yard and prop the mast at the right angle. The key is getting a drill properly central.
A carbide burr in a dremel might also work.

 

[Robert Wilson]

May already have been mentioned, if so sorry to repeat.
When I had to remove main/bottom sheeve, with same looking problem, my "man-with-the-big-tool-bag-and-big-bill" advised me to gently tighten the screws a fraction first. I applied WD40 and as much pressure on the screw-driver (into the head, not the turning moment) as I could muster, and uttered a prayer. The screws tightened a fraction, and I mean a fraction. Then a gentle unscrewing effort.
It worked for me.

Good luck.

P.S. when I had to remove my mast foot all I had to do was drill-out 8 rivets. Lucky man!