Gin pole mast raising

[seanmcgrath]

I'm sure this topic has been covered, so maybe somebody would be kind enough to direct me to a link for raising the mast on my 23 foot Kells. I'm looking for gin pole ideas. Thanks so much.


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[CarlF]

I'm not sure of your boat size. This is easy for boats under 30 feet. Larger boats take a lot more care. Just google mast stepping and look under images.

I've done it with an "A-frame". This keeps the mast from falling off to the side.

Here's an amazingly detailed video someone did:

https://www.youtube.com/watch?v=li7SadZL8ek

[TurninTurtle]

The gin pole redirects the force on the line being used to raise the mast.

Without the pole the line would tend to lay along the mast and tension on the line is mostly attempting to make the mast shorter. Essentially zero force is working to lift the mast.

The gin pole changes it to a triangle of forces which will lift the "top" of the mast and pushing down at the step.

As the mast goes up the gin pole leaves the force triangle, (in most cases... not the one in the video) with the line used to raise the mast rising off the pole. As the mast becomes more vertical it requires less tension on the line to raise it further due to the geometry of the forces.

Actually, this is all applying High School Geometry and algebra to real life...

****************

I use bungees to have light tension on the side stays which does a wonderful job of keeping the mast from waving from side to side as it goes up.
You need to ensure you have blocks of some sort to prevent this from kinking the stranded stainless wire stays.

[seanmcgrath]

Thanks, that's what I was looking for. Turtle, could you elaborate on where the blocks would be needed?


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[TurninTurtle]

The blocks I am speaking of are med-large dia pulleys (blocks in sailing) such as a 4 inch clothesline pulley (for a lighter mast like mine) for the stainless stay line to ride in instead of kinking around the hook at the end of a bungee cord.

These are just for controlling the stays and adding SOME tension as you raise the mast. This stabilizes the mast and keeps the stays from hooking random stuff. (which can rip fittings out of the deck when solo raising a mast if you don't see the stay hook something...)

[MartinF]

Be careful! A 23-footer has a pretty heavy mast. If it decides to move sideways when half-way up it can do some expensive damage. One man standing (insecurely) on the coachroof may not be able to stop it. Nor will the A-frame or shrouds. Think about having two lines from the main halyard at the masthead to helpers on the ground.
M

[UNCIVILIZED]

If you look in the Searunner (Trimaran) construction manual, there may be pics & a description of such arrangements in there. as the smaller 2 models had masts designed for DIY raising.
It's at the Outrig Media site, or is findable too via the names; Jim Brown, & John Marples

[gbowen]

I raised a steel mast with a tabernacle and a gin pole. It was a 35 ft mast on a 42 ft boat. I had a substantial tabernacle and gin pole. The winch used was the anchor windlass. It went very well and saved the cost of a crane. The shrouds were used for stability and I had the help of a couple of friends. I did the math on this because I wanted to make sure everything would be OK. I'll look for the calculations and photos.

Regards,

gbowen

[wildman]

Apologies to OP who asked for a gin pole, but a Kells 23 mast could be raised with a bungee system (shown, below, on a Nimble 20). More here: Using photobucket

[seanmcgrath]

Thanks all for the help. Martin, there's not much problem putting it up with two people, but I'd like to be able to step it myself for those days I'm alone. The boat is a Kells 23, a light weight production boat of the mid 70's. The mast is rather light but unwieldy of course.


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[Bor the Wolf]

Originally Posted by MartinF

Be careful! A 23-footer has a pretty heavy mast. If it decides to move sideways when half-way up it can do some expensive damage. One man standing (insecurely) on the coachroof may not be able to stop it. Nor will the A-frame or shrouds. Think about having two lines from the main halyard at the masthead to helpers on the ground.
M

Sideways movement is best prevented by a set of special mast lowering shrouds. They are shrouds attached to pivot points in line with the mast pivot pin. This ensures the tension on the lowering shrouds does not change while the mast is lowered.

As an alternative, on some boats the main shroud attachment point can be moved up to line op with the mast pivot pin. Then the main shrouds double as lowering shrouds. This is how it is on my boat. I have a stainless steel triangles on deck that allows the main shroud to stay tensioned while the mast comes down.

Other than that my A-frame is permanently attached to the boat. It was build by a yard in stainless steel. It follows the curve of the foot rail when not in use and the stay with the Genoa furler is permanently attached to the A-frame After raising the mast, all that needs to be done is to secure the A-frame to the bow, tension the back stay and we are on our way again. The system allows me to shoot bridges in 5 minutes or less.

[T_Cat]

I raise and lower the mast on my Catalina 22 every time I sail. To raise, I attach the gin pole, crank up the mast and attach the 2 lower shrouds and the fore stay. Too lower I attach the gin pole, release the 2 forward lower shrouds, and the fore stay. With the 2 lower shroud cables in hand, I guide the mast into the cradle. Easy.

[crazyoldboatguy]

I have been raising the mast on my Pearson Triton for many years. Heavier than the OP's spar I am sure. I use a bridle that attaches the upper shroud pivot point (closely aligned with the mast hinge pin) to to boom which triangulates the boom, shroud and mast. The boom provides the leverage and the sheet (4 X purchase) does the lifting. The topping lift does a lot of heavy work - made of Kevlar- I actually use 2 of them, the current one and the back-up one now in place as a back-up main halyard. Has worked well for 15 years.

[ptrailsail]

Hi!
I haven't tried it (my boats mast base has no pivot point) but take a look here:
https://stingysailor.com/2015/07/18/...-a-gin-pole-2/

[gbowen]

It looks like there was a lot of good advice given. My mast was big and heavy. My pivot point for both the mast and gin pole were on the tabernacle. tabernacle. My tabernacle and support were corresponding very substantial. The tabernacle was stepped on the coachroof and I set chain and shackle lengths to it to strengthen it athwartships. Beneath the tabernacle was a 4 x 4 steel tube that took the load to the keel ballast. The mast was raised on the water. I was going to write an article about it but it seemed a trivial problem so never had the motivation. I did scan everything though. Here are the scans as an attachment.

There are lots of articles over the years on this subject.

gbowen