Mast raising/lowering on small yachts : lateral stability

Looks interesting, but allows too much sideways movement for my mast foot. It would stop the mast going over sideways, but a gust of wind would move it 10 degrees or so, which would snap the mast foot.
 
I quite like the positive feedback principle when the mast goes to one side.

Attaching both deck liones to a single weight means that if the mast sways sideways, tension is increased on the side opposite to the direction of sway.

With a mod for a bigger mast and some means of making the whole device stand still at any point, I can see the system being developed well.
 
stevebrassett said:
Looks interesting, but allows too much sideways movement for my mast foot. It would stop the mast going over sideways, but a gust of wind would move it 10 degrees or so, which would snap the mast foot.
Click to expand...

Pretty sure my step would snap as well. Being alloy, I suspect it wouldn't make the 10 degrees even.
 
I am with Lakey.

It is way over complicating the problem for a small mast.

We use a simple gin pole system on a much heavier and larger mast(32')mast and roller reefing gear with jib fitted.
If the ropes were taken and fixed in length to a point in line with the mast pivot there is zero chance of breaking a mast foot or of the mast moving laterally.
 
From experience I can say that an A frame is MUCH more stable than a gin pole. With my A-frame and side stays I would happily get off the boat and go for a cup of tea with the mast halfway up!
 
I had a trailer sailer and hated raising the mast, no so much due to the weight but the lack of lateral stability, a puff of wind at the wrong moment could have a disaster as its very hard so stop the mast going off to one side while its above your head and the shrouds have no tension. I though it would be easier if fulcrum of the shrouds was at the same level as the mast foot and then you would have more stability.

My new boat is gunter rigged and the shorter lighter mast can be raised one handed with no fuss. Gaff or gunter rigs have a lot of advantages on boats that are to be trailed

(Im sure someone will be along soon to point out the disadvantages)
 
CreakyDecks said:
From experience I can say that an A frame is MUCH more stable than a gin pole. With my A-frame and side stays I would happily get off the boat and go for a cup of tea with the mast halfway up!
Click to expand...

I think the secret is in the side stays. I would be just as happy to join you for Tea whilst leaving our stayed gin pole set up. Even in a cross wind or with a bit of swell side on. Gin pole (ex windsurfer carbon-fibre mast)does it for me as I can also use it as a pole for goose-winging the jib and it takes up a minimum of space in comparison to A frames.
 
TSB240 said:
I think the secret is in the side stays. I would be just as happy to join you for Tea whilst leaving our stayed gin pole set up. Even in a cross wind or with a bit of swell side on. Gin pole (ex windsurfer carbon-fibre mast)does it for me as I can also use it as a pole for goose-winging the jib and it takes up a minimum of space in comparison to A frames.
Click to expand...

To be honest I don't leave my A frame on the boat.
The main thing is that whatever people use it should be a bit of "Victorian over engineering". As NASA say, failure is not an option! Take out all the worry about something snapping or breaking and it becomes a totally different experience.
 
TSB240 said:
I am with Lakey.

It is way over complicating the problem for a small mast.

We use a simple gin pole system on a much heavier and larger mast(32')mast and roller reefing gear with jib fitted.
If the ropes were taken and fixed in length to a point in line with the mast pivot there is zero chance of breaking a mast foot or of the mast moving laterally.
Click to expand...

+1 - works well for me too. If it ain't broken, don't fix it.
 
Thank you all your constructive replies.The idea formed when a friend with a 10M sturdy ali mast worried how he might get the mast down,if he had to,while long distance single handed crusing, assuming that mast steps or crane were not available and that he hadn't made and didn't want to carry the components of an A frame - so only a gin pole.He has the benefit of a longish hefty mast deck mount bar with several drillings for large bolts (ideal for the pole) but the ali rails are not conveniently slotted,so setting up a triangle to match the mast pivot axis will probably entail drilling the rails.Hence the idea to use stays whose length is adjusted by a weight,and the test rig.
The turning pulleys for the temporary stays were deliberately placed well away from the axis,in order to test the system,so the travel required for the weight is large and the possible swing is also large.In fact the force required to push the mast off centre and the return force is substantial,and can of course be increased with a greater weight.But agreed it is not failsafe and was not devised for a close fitting mast pivot.The Z Spars mount seems particularly demanding and vulnerable and I'm not sure why it needs to be so tight.Is it intended to guide the mast to the centreline as it is hoisted,so accepting stress ?
'Walking Up' a mast is limited by your stature and the weight of the mast.Using 'three strong guys' is likely to cause damage unless there is exceptional co-ordination and a robust mount,but you might need them to shift the mast along the deck or get it to the ground.I find that the spreaders normally lie in the wrong place and prove the most awkward partt of the operation..
It seems that A frames alone act well to provide the side 'stay' function if they slide on the mast or as stable 'pylons' if they act as a gin pole but can't do both through the whole swing.
The ex windsurf mast deployed by TSB240 sounds interesting.I have been saving an HD wave mast for this kind of use but I wonder what end fittings you use that take the high thrust at the foot and top fixings in gin pole use and then allows the goosewing attachments ?
 
Interested to see how this is developed, but can't help thinking its over complicating a simple problem. I have no problem using a gin pole and rope stays.
 
A short length of chain fastened to the gunwale on each side of the boat. The chain is slack and may be lifted in the middle. Find the link which aligns with the pivot bolt with the chain tight and mark the link - this will take some trial and error with the chain length. Attach rope stays from mast to marked link. The rope stays will remain tight at any point of the lift.

IIRC this is described in one of Blondie Hasler's books.

Paul
 
bluerm166 said:
The ex windsurf mast deployed by TSB240 sounds interesting.I have been saving an HD wave mast for this kind of use but I wonder what end fittings you use that take the high thrust at the foot and top fixings in gin pole use and then allows the goosewing attachments ?
Click to expand...

See links below to photos.

https://dl.dropboxusercontent.com/u/79352891/Mast LIFT Lower Pics/PICT0013.JPG

Gin pole shaped to fit front face of mast and then pulled onto mast with ratchet strap threaded internally over a through bolt.

https://dl.dropboxusercontent.com/u/79352891/Mast LIFT Lower Pics/PICT0028.JPG

Front end has an Eye bolt with an eye nut underneath for attaching jib haliard. Two u bolts either side for side stays with spinnaker haliard threaded through as a safety precaution.
Pm me if you want further photos.

https://dl.dropboxusercontent.com/u/79352891/Mast LIFT Lower Pics/PICT0042.JPG

Big rig on a little boat!
 
Last edited:
I used a gin pole made from an old bit of steel tube with tabs welded on each one. One located on the pivot bolt in the small tabernacle (a tabernacle is better if you are doing it a lot) and the other bolted to the s/s strip on the roller reefing. A line led from the end of the pole - under the bow roller - and back to the mast so I could control the rate of descent (using an on-mast winch) and steady the mast as well.
I got down from the boat to take this picture. It's all just supported by that line to the foredeck bollard.


12mastbeinglowered.jpg
 
Lakesailor said:
I got down from the boat to take this picture. It's all just supported by that line to the foredeck bollard.

12mastbeinglowered.jpg
Click to expand...

Try it with the boat rocking on a swell or in a cross- wind Phil!

You will soon break your mast foot off if you don't have a strong tabernacle and/or any side stays. Temporary side stays take away the risk of mast falling over sideways especially if its a big un!
 
You must log in or register to reply here.

Share this page

Top