Mast raising quandry

doehunter · Jul 9, 2011

davenlynn said:
So - - - Today I installed my mast raising system on my Mac 25. I've got a gin pole (7') installed at the forward base of the mast. A double pulley at the top of the gin pole and another tied to a horn cleat at the bow, just aft of the forestay attachment point. I attached the jib halyard to the other side of the gin pole, ran it through the jib pulley and made it fast to a cleat on the mast. The gin pole was set at a 10 degree angle from the vertical to aft. I ran the working end of the block and tackle line through a couple of fairleads and back to the starboard winch. All lines were taut and clear. I cranked and cranked and nothing happened. It got to a point where I couldn't turn the winch handle any more, but the mast never moved up from the rear support crotch it was laying on. Basically I rigged it just as "Sumner" did, with baby stays 6' up from the base of the mast and 2'2" out on each side. After reading some of the replys here, I'm wondering if the mast needs to be raised to a certain angle by hand (or crook?) before the raising jig will work. Am I correct?

Signed,

Stymied in San Diego
(Dave) ShareThis

Hmmm?
My set up is similar to Sumner's, and what yours sounds like except my gin pole is only about 5 ft. When I did use it, it was pretty hard to get started. As the mast goes up the geometry changes and winching gets easier. When it's all rigged and ready to go, can you lift the mast by hand? There shouldn't be anything binding. Could the rigging be holding it down?
Jim

Sumner · Jul 9, 2011

Hard to see above, but this is where the mast would be sitting before going up. It is on a crutch at the stern....

....that was on the boat when we got it.

Now with the solar panels....

...it is even higher.

Still we never had the problem you are talking about with the crutch. With the gin pole it shouldn't make much difference how high the mast is when you start as that angle stays the same with the exception of a small difference in the angle from the top of the gin pole down to the fitting on the foredeck.

Of course as the mast gets higher and higher more of its weight is on the deck and you are lifting less and less weight. This won't be too noticeable until the mast is up 45 deg or more, yet any bit the mast is up at the stern of the boat will be less weight you are trying to raise.

Not sure what to tell you, but lift it some and see what happens and maybe you will get a clue as to what is wrong now,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

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timebandit · Jul 10, 2011

My answer is at the other post.

MrMikey64 · Jul 12, 2011

Maybe a pic of your setup will provide a clue as to where the problem is.

Sumner · Jul 12, 2011

MrMikey64 said:
Maybe a pic of your setup will provide a clue as to where the problem is.

I agree, is your block and tackle 2:1, 3:1 or 4:1. Ours is 3:1....

http://www.k7nv.com/notebook/id8.htm

Also as TB has stated there might be a time when you want to raise or lower the mast on the water. When we finished our Lake Powell trip a friend was bringing the Suburban/trailer to us way after dark and there were no lights at the ramp, so we took the mast down on the water while waiting for him to come.

Also if something broke on the water one might want to take the mast down. We carry the gin pole and block and tackle with us on the water along with one or two other things

.

I believe others have pulled the mast up with the winch on the trailer, but one thing I see as a negative is that it takes a lot of cranking on it to make the line go very far. If I was going to go that route I might put a low cost, under $70, electric winch on the trailler and use it.

I have one that I use on a 2 wheeler at times....

Good luck,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

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timebandit · Jul 12, 2011

Pictures would be helpfull.

I just use a 3 to 1 and no wench so I can not imagine what could be wrong.

Your discription seems ok, but lots of people do not need an electric wench.

Sumner · Jul 12, 2011

davenlynn said:
My block and tackle is 3:1. I like the idea of an electric winch and have considered mounting one on the tongue of the trailer. Mounting one on a cart never occured to me. Wouldn't you have to brace it against something to provide tension? Perhaps I'm missing something. I can get a real nice 2000 lb capacity 12V winch for about $75, just thought I'd try the hand winch first to see how it works.
I checked my layout and nothing is binding, at least that I can find.

Thanks,

Dave

I use the 2 wheeler to move it where I want to pull something and then put a cable or chain to where the arrow is and the other end to something that won't move.

I agree with TB though that you shouldn't need an electric winch to pull the mast up. Something is not right. The gin pole, 3:1 block and tackle and the boat's winch should do it easy.

I'd only go elect. if you were actually going to use the one on the trailer as winching a long pull with the trailer winch I would think would be slow,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

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caguy · Jul 12, 2011

Your crutch looks a Little low. Try raising the mast as high as you can before pulling with the winch. The first few feet are the hardest. It seems to get exponentially easier the higher the mast is raised. The longer your gin pole the better also but yours looks long enough. I use the mainsheet blocks with a 4:1 purchase.

bricon123 · Jul 13, 2011

caguy said:
Your crutch looks a Little low. Try raising the mast as high as you can before pulling with the winch. The first few feet are the hardest. It seems to get exponentially easier the higher the mast is raised. The longer your gin pole the better also but yours looks long enough. I use the mainsheet blocks with a 4:1 purchase.

I agree that the crutch is a little low to do a straight pull. In engineering circles it's known that at around 18 to 20 degrees on a line, you are more pulling an object forward than upwards. This also applys to when you are dropping the mast, somewhere around 18 to 20 degrees you are no longer holding an object up, so the mast crashes down that last few degrees. Think of a triangle, the deck, the forestay and the gin pole line. Its those lines that form the degree of pull, so the higher the mast crutch, the less accute the degree. But the same works for the Gin pole. The taller it is, the higher the degree for the initial pull. My mast raising contraption (home made) is 12' tall when deployed specifically so I can pull the mast up (and lower to) from my low crutch level with little effort. 3:1 pully system by hand.

Sumner · Jul 13, 2011

bricon123 said:
I agree that the crutch is a little low to do a straight pull. In engineering circles it's known that at around 18 to 20 degrees on a line, you are more pulling an object forward than upwards........

Just wondering whose pictures are you guys looking at? I haven't seen any pictures of his setup yet, just ours. Did I miss them somewhere?

This is our boat...

.... and we don't have a problem.

The mast is low, but the pull angle is not to the mast, but from the foredeck up to the top of the gin pole. The length of the gin pole determines the lever arm that you are using to try and lift the mast and as you mentioned the angle of pull on that lever arm will come into play as to the total effort that is required. Above you can see that the angle from the deck up to the top of the gin pole isn't too bad of an angle considering what we are trying to do. If the gin pole was longer the lever arm would be longer, better deal, but the pull angle would get worst.

The weight you are trying to lift is determined by the weight of the mast and where the line from the gin pole to the mast is attached to the mast. If that line was attached to the very top of the mast and it was horizontal you would be lifting 1/2 the weight of the mast since one end would be resting on the deck and the other end would be held up by your gin pole/block and tackle. Just as if you and someone else were carrying the mast and each of you was at the end of the mast.

The problem is if you use the jib halyard and it is not at the top of the mast then you are lifting more that 1/2 of the weight at first. Imagine one person lifting the mast at the end and the other lifting the other end say 10 feet in from the end. The second person would now have more than 1/2 of the weight.

The gin pole is attached to the mast with the jib halyard which in our case is attached down the mast some. So at the beginning of the lift you are lifting all of the mast's weight from the halyard attach point to the top of the mast and and also 1/2 the weight between where the jib halyard attaches to the mast down to the mast base. You are lifting a lot of weight at that point, more than 1/2 of the masts total weight.

As the mast goes up, more and more of the mast's weight is now down at the foot of the mast until at vertical all of the weight is down on the deck. Also as the gin pole is pulled down towards the deck the pull angle gets better there so it gets a lot easier to pull the mast the last part with the good angle and less and less weight that you are trying to lift.

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

justsomeguy · Jul 13, 2011

davenlynn said:
So - - - Today I installed my mast raising system on my Mac 25. I've got a gin pole (7') installed at the forward base of the mast. A double pulley at the top of the gin pole and another tied to a horn cleat at the bow, just aft of the forestay attachment point. I attached the jib halyard to the other side of the gin pole, ran it through the jib pulley and made it fast to a cleat on the mast. The gin pole was set at a 10 degree angle from the vertical to aft. I ran the working end of the block and tackle line through a couple of fairleads and back to the starboard winch. All lines were taut and clear. I cranked and cranked and nothing happened. It got to a point where I couldn't turn the winch handle any more, but the mast never moved up from the rear support crotch it was laying on. Basically I rigged it just as "Sumner" did, with baby stays 6' up from the base of the mast and 2'2" out on each side. After reading some of the replys here, I'm wondering if the mast needs to be raised to a certain angle by hand (or crook?) before the raising jig will work. Am I correct?

Signed,

Stymied in San Diego
(Dave) ShareThis

I think you're losing some leverage where I boldly quoted you. Try attaching/tying/looping the jib halyard directly to the gin pole from the jib block, not from the gin pole to the jib block and down to a cleat on the mast. G'luck. Tom

justsomeguy · Jul 13, 2011

Sumner said:
Just wondering whose pictures are you guys looking at? I haven't seen any pictures of his setup yet, just ours. Did I miss them somewhere?

http://purplesagetradingpost.com/sumner/macgregor/macgregor-links-1.html

I was wondering the exact same thing.

Sumner · Jul 13, 2011

justsomeguy said:
... from the gin pole to the jib block and down to a cleat on the mast. G'luck. Tom

Tom that is the way I setup ours. I attach the jib halyard to the top of the gin pole. Then it goes up to the block that is up on the mast where the forestay attaches. Then it goes down to near the base of the mast and is cleated off onto the mast where it normally cleats off. It runs just the way it does under sail.

Depending how much you let the halyard out or pull it in will set the angle of the gin pole to the mast and like he says it needs to be raked back so that when the gin pole approaches the deck to pin the forestay there is room for the block and tackle between the gin pole and the deck.

I still can't really 'read', not 'see', anything wrong with how he is describing how he rigs the system.

Again if you are dealing with a roller furler the gin pole really makes raising the mast with it easy even by yourself. Here is a picture of someone else's boat and I....

...just copy them, but I put the furler higher on the gin pole. Just takes a minute to tie it there and it comes down to the deck without dragging on the deck as the mast goes up.

We also use a Johnson lever and that really simplifies pinning the mast and keeping the proper tension on the forestay without having to mess with the turnbuckle once you have it set where you want it.

Winch the mast up, untie the furler from the gin pole., attach the forestay/furler with the Johnson lever, snap its lever over-center and pin it and you are done and have a forestay with good tension on it. More than you can ever get without twisting the turnbuckle open and then closed after pinning the forestay. A one person job where you can stop at any step,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

justsomeguy · Jul 13, 2011

Sumner said:
Tom that is the way I setup ours. I attach the jib halyard to the top of the gin pole. Then it goes up to the block that is up on the mast where the forestay attaches. Then it goes down to near the base of the mast and is cleated off onto the mast where it normally cleats off. It runs just the way it does under sail.

You're slightly lowering the angle of force applied by running the halyard down to a cleat on the mast. Couldn't say how much, but it is a factor in the equation requiring more power than if it were run straight to the block itself. This is why a longer gin pole has an easier time than a shorter one. Think of the angle the block assumes when pulled by each method.

Sumner · Jul 13, 2011

justsomeguy said:
You're slightly lowering the angle of force applied by running the halyard down to a cleat on the mast. Couldn't say how much, but it is a factor in the equation requiring more power than if it were run straight to the block itself. This is why a longer gin pole has an easier time than a shorter one. Think of the angle the block assumes when pulled by each method.

Maybe I'm missing something or we are talking about something else, but if the line went from the gin pole to the block up on the mast and was tied off right there I don't see the difference in tying it off lower once it has passed through the block. The mast, the block and the cleat are all moving together and the jib halyard from the block to the gin pole is moving with them and is always the same length and angle.

If you tied it up on the block how would you release it once the mast is up?

You might have to draw me a picture and post it for me to change my mind on this

,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

Phyrexii · Jul 13, 2011

This is my rig, which is slightly different. I installed a second 'step' on the deck just ahead of my mast step. This is a 4x4 block with two support plates on either side. I drilled a 1 1/2 dia hole 3" deep in the center to receive my 'winch pole'. (I also made a mast support that drops in the hole to support the center of the mast when transporting the boat).

The winch pole is simply a piece of 1 1/2 conduit about 5' long. I run a line from the top of the pole to the forward cleat for support. I then bolted a winch at a comfortable spot to the pole using a couple of U-bolts. I have a line going from the winch, thru a block at the top of the pole, to the mast - where I've attached my baby stays. Then I simply winch the mast up, easy as pie.

When I'm done, I just store the pole under the cockpit. Very easy to set up and use.

Mast raising quandry

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