OK - one for the DIY 'rs - Mast Chainplate addition

[Refueler]

My boat has inverted U bolt shroud / stay fastenings to Toerail. They sit significantly lower than the deck stepped mast base / pivot.

A number of threads over a period have always prompted me to consider adding an extra chainplate point either side of cabin top to enable an additional temporary stay to be made while raising / lowering mast.

The question is - should I create permanent chainplate either side or removable ?

I have good proven A Frame setup ... but lacks that sideways prevention ...... It's ok at my home - my channel is quiet and I am fine on my own ... but in Harbour after passing bridges - its not so - can easily have wash from fishing boats / other yachts .....

It would mean a backing block on inside of cabin to take the bolts ... a permanent I would think best as a triangle shape ... two bolts to cabin - single hole for temp stay shackle. Removable ? a simple straight plate with single bolt to backing block that has an expander thread embedded in ??

I have considered using lines from existing caps led forward to alter their pivot point .... but feel as a lone hand - it might be better to have a more serious solution .....

 

[thinwater]

On my F-24 there are a separate set of lighter duty shrouds to the cabin top that are only for mast raising. Clutter, really, but it works if the boat is dead level. Not really a wide enough base and owners have broken mast hinges.

I have seen people create a triangle from cable that connects the existing slightly aft chain plate, to a point in space level with the mast base above the toerail, and on to another new plate about 4' forward (two separate cables combined wit h a small rigging plate. This plate is also connected to a short cable to the existing plate approximately abeam the mast. The abeam shroud is then connected to the apex of the triangle (the rigging plate), and that becomes the pivot point when lowering. The aft shroud slacks, but the beam shroud stays snug throughout the process.

 

[Refueler]

Yes - I have seen the 'cable triangle' .... it does have one flaw though ..... and is why I did not try it before.

As the mast lowers ... the line drawn from mast to fwd anchor point of the 'cable triangle' also lowers allowing the keeper plate to drop below mast pivot.

I did see a variation of it .... where guy had the same two cables in a V ... but instead of a keeper plate - he used a long vertical plate clipped to cap shroud base point - tall enough to hold the V cables in line with mast pivot even as mast lowered.

When you think about it .... any solution that raises the Cap Shroud attachment to mast pivot level should work ... the trick is to keep that point fixed as the mast lowers / raises.

With the cabin side extra chainplates - they would not be able to move 'inwards' as well ....

mmmmmmm brain food !!

 

[Refueler]

OK ... been hashing this around the brain cells ...

I think a combo of 'thinwaters' V bridle and a vertical plate to V apex from Cap Shroud toerail can be answer ... saves all that drilling and then cosmetics to finish off the backing plate.
I have suitable pipe I can cut and drill to make the verticals.

Once winter starts to ease off ... I will be pursuing this further as I need to move my boat down coast to Pavilosta Marina where guys will be replacing wood rubbing strake and making new Sprayhood and covers.

 

[38mess]

On my 22footer we took the mast down with the help of a long ladder at the front with two blokes holding it, and two of us lowering the mast on to the ladder with a winch. Getting it back up was in reverse. The mast is heavier than it looks and is extremely unwieldy. (Aluminium)
Edit
Sorry wrong thread ?

 

[Refueler]

On my 22footer we took the mast down with the help of a long ladder at the front with two blokes holding it, and two of us lowering the mast on to the ladder with a winch. Getting it back up was in reverse. The mast is heavier than it looks and is extremely unwieldy. (Aluminium)
Edit
Sorry wrong thread ?

No worries here mate .... I'm not one of the forum clique !!

 

[slawosz]

I know you sorted mast step last year, but actually - if you are after DIY - and looking at your channel you are (fellow Ender owner!), I would consider changing mast step:

This one is from Sabre 27. I am pretty sure that even A2 steel will be enough - especially in Baltics.
You can then create sleve (you can 3d print it), and reinforce like here:

to strenghten the pivot point - however I would rather use carbon tape instead.
See how mast is being hoisted on the Dehlya 22:

PS. Recently I was thinking about printing brackets to be strengthened with carbon tape, but sadly, I don't have the facilities to safely make break tests...

 

[Refueler]

I wanted to swap to a full tabernacle - but the mast gear is fitted too low preventing any real height of tabernacle.

I have halyard winch ... cleats ... all sorts low down on mast .... to move them up ?? I'd be weakening mast.

Have a look at the mast base .... I know its not best ... but you then have idea what I mean .... (Yes that's getting back to my back garden mooring) .....

 

[alahol2]

I have seen a boat where the lower part of the main shrouds is replaced (permanently) by a steel bar. The steel bar is triangulated to the lower shroud bases when mast lowering.
See the photo (from the Yachtsnet archive) about half way down this page.

 

[Refueler]

I have seen a boat where the lower part of the main shrouds is replaced (permanently) by a steel bar. The steel bar is triangulated to the lower shroud bases when mast lowering.
See the photo (from the Yachtsnet archive) about half way down this page.

I see that ... but surely the bar must be locked vertically ?? If not then its pivot point will still be the chainplate ?? The photos I see have a narrow bar only ??

 

[Refueler]

More I think about it ...

If a metal T piece was made ... horizontal bar bridges the chainplates ... the vertical section rises to higher than mast pivot. At mast pivot level a shackle can be used to lock the Cap Shroud to the vertical .... this would provide the required support ?

 

[Spirit (of Glenans)]

Post deleted.

 

[VicS]

More I think about it ...

If a metal T piece was made ... horizontal bar bridges the chainplates ... the vertical section rises to higher than mast pivot. At mast pivot level a shackle can be used to lock the Cap Shroud to the vertical .... this would provide the required support ?

Won't this bend the cap shrouds excessively as the mast is lowered?

I use an A frame in a similar way to you but its feet rest against the raised mast support beam across the cabin top.
My boat has swept back spreaders so the cap shroud anchor points are aft of the mast but the single pair of lowers are in line with the mast. I have often thought of fitting chain plates to the cabin sides, extended up to the level of the mast pivot for the shortend lowers. They would then provide good lateral stability during mast raising and lowering

 

[alahol2]

I see that ... but surely the bar must be locked vertically ?? If not then its pivot point will still be the chainplate ?? The photos I see have a narrow bar only ??

As I understood it, the top of the bar is held in position by rope strops to the fore and aft lower shroud fixings. Never seen it work but it should (in theory)...

 

[Daydream believer]

I saw a dutch boat with 2 metal hoops at the chain plates & the shrouds attached to them on the pivot point. The A frame being pivoted to the shroud base. The apex of the a frame took the furler & also fixrd to the deck. It also had a wire to the anchor winch. As the boat approached a bridge the owner released the bow clip & lowered the mast to approx 30 degrees. The top of the A frame was level with the tip of the mast. He then motored under the bridge. When through, the anchor winch pulled up the mast.
It occurs to me that you could fix the main shroud to the loop & the aft shroud would go automatically slack. It might be worth fixing the forward shroud to the A frame so that it goes slack at the same time as the A frame raises. It means pivoting the A frame further aft but a bit of geometry MAY mean that one can just let the a frame go & the mast will lower enough to go under the bridge.

 

[Refueler]

Hi DB ....

That would be dandy - but with the short foredeck and clutter - I cannot get A-Frame to sit low enough to connect forestay to it ... so I have to handle Forestay separately - while A-Frame uses spinnaker and stormsl halyards.

Hard to describe - but believe me - I tried.

To get under the bridges - I can manage with mast down to about 45deg ... so not needed to go all way down ... BUT I do as then mast is secure in Y cradle at rear ...

If I sort the side pivot level - I can do away with the Y cradle except when lowering for storage.

 

[William_H]

Hi Nigel. The idea of additional shrouds to chain plates on cabin top is good. However the additional chain plates will presumably be mounted on cabin sides. So will have extend upwards I imagine like 20 cms to reach level with pivot. Shape it to take load at 45 degrees down to 90 degrees. If you don't mind that lump on cabin top that would be best. The stay itself can be permanent or temporary. Should not need a huge strength.
The extension of the chain plate with a tube or bar is common around here. Is permanently stayed forward to force it vertical even with load pulling sideways.
A cheaper but less effective way to keep cap shroud tight in traverse is to fit a clamp to shroud cable at or above mast pivot height. A line tackle runs from clamp forward to gunwhale such that mast 45 degrees it makes a straight line tackle attachment up shroud to mast top. This will control much of potential mast sideways swing. Even more if the tackles extend aft so can be tightened as mast goes down. ol'will

 

[Refueler]

All good stuff ....

I hope that my asking all this and peoples replies may help anyone else with similar. There are many ways to accomplish this .. and lets hope all works.

Using existing Cap Shroud ..... because of the frequency of mast up / down and I don't want to disconnect from toerail fastening .. I'm a little concerned about the 1x19 being 'bent' at the higher pivot point if clamped. I have to admit that I do everything possible to avoid any sharp angles to my stays when working the mast. This makes me think 'away' from using the Cap Shrouds themselves.

Lets think about it ..... to lower the mast - I must disconnect forestay (furler) ... and fwd lower stay each side ... Baby / Inner - whatever your neck of woods calls it ...
The forestay as I said cannot be used on the A frame as I cannot lay A frame low enough to connect. I use the spinnaker and stormsl halyards.
If I have an inverted T bar from side chainplates - I could use that fwd lower as side preventer each side..... no need for metal clamp ... a decent rolling hitch can do it.
Or back to having a temp rope stay each side ....

Chainplate to cabin side .... I'm not actually against this .... my cabin top design has a similar arrangement as a 'toerail' that runs its length each side ..... with a deep channel inboard ..... see here :

As we see here ... the mast sits in line with the teak handrails ..... awkward as I do not really want to interfere being able to grab the handrail. I do not think the handrails would be suitable for fastening the side preventers to ....

Its looking like back to actual chainplates .....

Thoughts ??

 

[William_H]

Hello Nigel re above picture and discussion re stays for holding mast centre in traverse down. If you had the inclination to try it I would suggest using the forward baby stays disconnected and moved back. Attach to that lovely teak grab handle. You might need a clamp on stays and use rope to attach to handle. It looks a bit like aft end of handle is aprox aligned to mast but lower than pivot. There will be some discrepancy from perfect alignment so will go looser. Perhaps you can better assess significance of miss alignment or as first said give it a try at home . I wonder if heavy bungy cord introduced between handle and wire might be adequate to take up looseness and keep mast central. Or even raise the handles on blocks to align to mast pivot. ol'will

 

[Refueler]

Hi Will ...

I'm reluctant to use the handrails as they are original to the boat of 1973 !! They appear and feel good as hand holds ... when sanded and stained - look good .... but who knows what real strength is left in them. If I break any - devils job to replace.

There is another way .....

My mast foot sits on a blade with multiple pivot holes - I can adjust mast position ..... each hole can take a 10mm diam bar through .... wondering whether I can pass a threaded stud bar through with a nut either side to lock in place ... v rope at each end to chainplates to stop it being bent / pulled out of alignment ... then short stays to keep mast central ?

If only weather was 'kinder' ..... I'd go down and measure up properly.