How would you redo this Mast Base?

[Swenns Dad]

Hi all.

As you may already have seen from a previous post, my ally mast base was totally shot and needs to be replaced. As the OEM unit is obsolete, I’ve found a company who make a replica.. but it’s £400 and a 3-4 week lead time.

So.. pictures attached to paint a picture...

I’ve found an engineering company local to me who have offered to fabricate me a new one, at half the price... so I’d like to know, would you have a like for like made.. or would you, after reading the next few statements, have something slightly different made (which is now an option).

1. There was a wedge shaped timber packer between the mast base and deck (rotten). It was approx 10mm thicker at the front edge than the rear. I assume this was to trim the angle of the mast base...
2. The cabin roof between the base fittings is approx 6mm depressed in the middle

So, question is... would you make the new base the same as old and replace the timber wedge, or have the new base made with this 10mm offset (ie, no need for wedge).

Would you make the new base a little longer, with a few eyes to attach halyard?

Any recommendations welcome...

 

[Swenns Dad]

Hi all.

As you may already have seen from a previous post, my ally mast base was totally shot and needs to be replaced. As the OEM unit is obsolete, I’ve found a company who make a replica.. but it’s £400 and a 3-4 week lead time.
View attachment 87924
So.. pictures attached to paint a picture...

I’ve found an engineering company local to me who have offered to fabricate me a new one, at half the price... so I’d like to know, would you have a like for like made.. or would you, after reading the next few statements, have something slightly different made (which is now an option).

1. There was a wedge shaped timber packer between the mast base and deck (rotten). It was approx 10mm thicker at the front edge than the rear. I assume this was to trim the angle of the mast base...
2. The cabin roof between the base fittings is approx 6mm depressed in the middle

So, question is... would you make the new base the same as old and replace the timber wedge, or have the new base made with this 10mm offset (ie, no need for wedge).

Would you make the new base a little longer, with a few eyes to attach halyard?

Any recommendations welcome...

 

[anoccasionalyachtsman]

Definitely incorporate the wedge - the builder would have if he'd had the choice. Probably wouldn't have had to bollock the designer for being incapable of deciding where the mast might be best placed....

And definitely more attachment points, there's always one too few.

 

[Swenns Dad]

Definitely incorporate the wedge - the builder would have if he'd had the choice. Probably wouldn't have had to bollock the designer for being incapable of deciding where the mast might be best placed....

And definitely more attachment points, there's always one too few.

What additional points would you fit... ?

 

[lw395]

I'd be more concerned about the deck being depressed 6mm across that distance.
The mast base doesn't actually do very much. It just locates the bottom of the mast, not against huge forces.
The pad under it needs to take the compression load and the wood should never have been allowed to get that bad.

 

[lw395]

What additional points would you fit... ?

I'd say attachments for foot blocks for halliards etc. Do you have all you want? Might you want to lead back reefing lines? Now's the time to put the hooks in places so to speak.

 

[Swenns Dad]

I'd be more concerned about the deck being depressed 6mm across that distance.
The mast base doesn't actually do very much. It just locates the bottom of the mast, not against huge forces.
The pad under it needs to take the compression load and the wood should never have been allowed to get that bad.

So, any comments on the mast base itself? The compression is another matter, which I’ll have to deal with somehow...

 

[anoccasionalyachtsman]

Yes, as @lw395 says, something to shackle to, gives flexibility.

 

[anoccasionalyachtsman]

And, while I think of it, a forward projection that would stop people standing on your deck plugs?

 

[Swenns Dad]

And, while I think of it, a forward projection that would stop people standing on your deck plugs?

I was thinking about projecting fwd... I could tidy up the plugs. Would you extend it so far as to also cover the u bolt behind the hatch?

 

[BabaYaga]

No chance something like this might suit?
T-Järn 70x180 | Benns
A lot less than £200....

 

[neilf39]

if you run a straight edge fore and aft and then across the deck where the mast foot is how much is the deck depressed in that area? I wonder if the wedge was put in to compensate for deck compression so the rigging could be tightened up. If there is compression I would get the deck sorted out underneath so no wood is required. If there is no significant compression I would have a thicker fitting made so no wood is required.

 

[Swenns Dad]

if you run a straight edge fore and aft and then across the deck where the mast foot is how much is the deck depressed in that area? I wonder if the wedge was put in to compensate for deck compression so the rigging could be tightened up. If there is compression I would get the deck sorted out underneath so no wood is required. If there is no significant compression I would have a thicker fitting made so no wood is required.

There a 6mm depression running aft to fwd...

 

[Swenns Dad]

No chance something like this might suit?
T-Järn 70x180 | Benns
A lot less than £200....

Too small.. ?

 

[doug748]

I like your previous idea of using Tufnol under the fitting. Make it well oversize and you can add whatever blocks you require later. For economy, convenience and ease of brainwork get the old step welded up.
Us the existing screw/boltholes.

 

[Swenns Dad]

The existing step is, quite literally dust! Nothing salvageable.
My concern about putting a wedge under the new base (be it wood or Tufnell) is it adds another place for saltwater to stagnate...

 

[lw395]

There a 6mm depression running aft to fwd...

What's supporting it underneath?
I'd suspect it might be a slab of ply moulded into the deck. If that is soggy and rotten, I'd want to know how far the problem extends.
If the deck has lost its rigidity, your new step will break its seal and let water in as soon as the rig tension goes on.

 

[Swenns Dad]

What's supporting it underneath?
I'd suspect it might be a slab of ply moulded into the deck. If that is soggy and rotten, I'd want to know how far the problem extends.
If the deck has lost its rigidity, your new step will break its seal and let water in as soon as the rig tension goes on.

Although I haven’t physically inspected the core, it is solid (as tested with tap hammer... prodded in vicinity of bolt holes). I’ve also asked a surveyor what he thinks.... he’s on the fence (ie, signs are that it’s solid... but clearly depressed). He suggested it could be as a consequence of the post under the foot settling... but that’s almost impossible to verify.

Need to be realistic about how much of the cherry I bite off... I was considering cutting out the deck under the foot and setting in a Tufnell base... see attached... but again, how far to I go!

 

[anoccasionalyachtsman]

Given that the normal horizontal plinth wasn't designed in, are you sure that the post is actually under the mast? Are there any fixings common to base and post?

 

[Swenns Dad]

Given that the normal horizontal plinth wasn't designed in, are you sure that the post is actually under the mast? Are there any fixings common to base and post?

The post is, approx directly under the pad... but as you can see, there’s no direct fixtures.