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Mast Lowering and Raising

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KD4AO
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USA
202 Posts

Initially Posted - 02/18/2009 : 10:54:54

Is it possible for one person to lower the mast at the dock without a gin pole? Or is it too heavy to handle? How about with 2 people?

Bob Townsend

Past C250 Chief Measurer
Past owner of:
C250WK #704
Honda 9.9

Punta Gorda, Fl.

Have a Great Sail!

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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4479 Posts

Response Posted - 02/18/2009 : 11:12:16

It could probably be done, but the last few feet would be tricky at best. Once the mast gets past 45° or so your mechanical advantage quickly dissipates and the mast is coming down no matter what. On my San Juan 21, I could do this because the mast was fairly light, and the step down from the coach roof to the cockpit seats wasn't very high. On the 250, the step down is a couple of feet, and you'll have the weight of the mast on your shoulder, which is not insignificant. If you could rig some sort of mast crutch to catch it at a point where you could safely step down to the cockpit w/o the weight, you could probably do it. The mast crutch could be wedged againt the fuel locker. If I were to do this, I'd round up at least two more people, the bigger, the better, so you could hand off the mast from standing on the coach roof to standing on the cockpit seats with a third person as a safety measure.

Two 12' 2x4's bolted together at one end and securely lashed to the baby stay eyes & stanchions would be a safer way to go.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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Response Posted - 02/18/2009 : 11:33:38

I agree with David, it is probably not a good idea to try it. I've done it once with three men and had no problem but would not do it with less.

As David points out, making an A frame is too simple and leaves no reason to enter the world of risk. When A frame mast raising was thought to need an articulating A frame, it was much harder but the standing A frame is the simplest and most evolved system.

[url="http://pages.suddenlink.net/arlyn/sailing/mrs.html"]Standing A frame[/url]

Edited by - on

KD4AO
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USA
202 Posts

Response Posted - 02/18/2009 : 15:26:01

Thanks guys, I understand but still wonder just what the actual weight of the mast is.

Edited by - on

Steve Blackburn
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1091 Posts

Response Posted - 02/18/2009 : 15:50:15

I think it could be done just by hand, but if ever you drop it, it will bust a hole in your cabin top. Don't ask me how I know. I'm guestimating the total mast weight to be about 100 lbs, that is if you are right in the middle of it. If it's still pinned down you experience a leveraging effect which will feel like much more than the total weight. Forget it, not a good idea.

Why do you want to take down the mast at the dock? I have a feeling that you need to get to the mast top. If so I did it with a bosun chair last season, but it was very difficult for my helper to raise my 180 lbs.

Edited by - Steve Blackburn on 02/18/2009 15:52:08

John Russell
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Response Posted - 02/18/2009 : 15:57:16

I'd imagine the mast itself is less than 150 pounds. One of these engineers probably knows how to calculate the downward pressure exerted and the perceived weight based on a given fulcrum. The risk, other than personal injury, is should the mast come down uncontrolled and hit the crutch described above at too great a speed, it will likely never be straight again.

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delliottg
Former Mainsheet C250 Tech Editor

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4479 Posts

Response Posted - 02/18/2009 : 16:05:02

I did some quick & dirty math on this with some assumptions.
Aluminum weighs 165lbs per cubic foot.
I assumed the mast was a 3x4 ellipse with a 1/8" extrusion
I assumed the mast was 35'
The math goes like this:
Area of an ellipse= pi *(major semi-diameter) * (minor semi-diameter)
That gives me 37.7 square inches for the outside diameter
and subtract 35 for the inner diameter
divide by 144 to get square feet
multiply by 35 to get cubic feet for length of mast extrusion
multiply by 165 to get weight of the mast
=108 lbs

If the extrusion is 1/4", double the weight (I couldn't remember off hand).

Caveats: I made a number of assumptions, so if this is within 15-20% I'd be happy with the result. Figure the mast is at least 120 lbs with spreaders, stays, lights, halyards, sheaves, etc. added in. And don't forget I might have the extrusion width wrong, which could double the weight.

Edited by - on

KD4AO
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202 Posts

Response Posted - 02/18/2009 : 17:00:48

Thank you all. I need to get to the anchor light and also to mount a Windex. I will start working on Arlyns idea, it looks like a much better plan. The weight is more than I imagined. I will also enlist a few neighbors to help. Thanks again. Bob

Edited by - KD4AO on 02/18/2009 17:24:09

bear
Admiral

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909 Posts

Response Posted - 02/18/2009 : 20:27:07

Bob, I have lifted the mast on "Brandy" and placed it in the forward mast crutch. I think your calculation is pretty close. Before I turned stepping over to my marina we tied a line to the jib halyard
and stetched it out from the front of the boat. Worked well Two souls out in front controlling the lowering and two souls on the cabin seats and/or the cabin roof. Baby stays are a must. JMTCW

Edited by - on

piseas
Former Treasurer

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USA
2017 Posts

Response Posted - 02/19/2009 : 15:32:30

Does anyone remember seeing a link one the forum to a video of a guy lowering and raising his mast on the water in the slip and doing it alone? He made it pretty simple looking.
Steve A
ps, I found it but is for a [url="http://www.youtube.com/watch?v=EsLxujYRsMQ"]C25[/url]

Edited by - piseas on 02/19/2009 15:37:37

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 02/19/2009 : 17:05:04

I've done mine single handed many many times but of course used a gin pole.

The original C250 setup was in some ways better for the single handed but all in all it was fraught with some failure points and the revised trailer system is safer.

The advantages of the early system was that no need existed to get off the boat, which left the operator in clear view to watch that no shrouds were fouled and if they did he was close and could extricate the snag and continue. And... of course no trailer was needed.

The disadvantages were that if a pelican hook on a baby stay didn't stay latched, the gin pole would roll over and the mast would fall. Fortunately I didn't learn this lesson but others have reported it. The other problem (also reported and not learned by this sailor) was the jib halyard that cleated to the gin pole sometimes slipped the hold of the jib halyard cam cleat. The instructions clearly said doing so would overload it and to carry the halyard to one of the mast horn cleats. I took those instructions as good.

At any rate, there were enough failures of the early system that Catalina abandoned it after the '95&'96 model years in favor of the trailer pole system that is significantly safer.

I still use the gin pole though it has been modified as a telescoping pole and uses a hand winch rather than the block and tackle. I'm careful to double check that pelican hooks are secure and that the jib halyard is cleated on a horn cleat.

Any one still using the original mono gin pole system should be cautious and realize there are danger issues.

The standing A frame system is much safer and in fact if the boat is setting level and there are no wake issues, baby stays are not needed.

Edited by - Arlyn Stewart on 02/19/2009 17:07:22

jbkayaker
Captain

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299 Posts

Response Posted - 02/19/2009 : 17:50:04

I recently had to take my mast down to install an antenna and thread the wire down the tube inside the mast. I used baby stays and found that they were considerably tighter with the mast all the way down than up. Next time I will leave the baby stays with maybe a half inch of slack at the pelican hook connection to the stanchions when in the up position.

I used what the guys at the sailing club call a "gin pole". It is a large telephone pole firmly set in concrete next to a boat slip. It has a 1 inch diameter rope long enough to go from the boat deck up through a pulley on a stout arm (chained on the opposite side to prevent it from bending down) about 45 feet up. From the pulley the rope extends down to a heavy duty sailboat winch mounted on the bottom of the pole. Is this mast handling device also properly called a "gin pole" ?

Edited by - on

zeil
Master Marine Consultant

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1314 Posts

Response Posted - 02/19/2009 : 19:04:11

During a 380 km Trent/Severn water way passage we raised/lowered the mast while in the water, away from truck and trailer...

We used an on-board gin pole, cut in half and sleeved in order to store below, with block and tackle attached in the anchor locker, baby stays and the stern mast support resting on the back center seat. Notice that the pop-top was left in place while lowering the mast. Although the mast is raised/lowered together, it could be done with one person. The only tricky time would be when the fore stay is detached from the block and tackle to be connected to the bow and tightened with the turnbuckle.

Edited by - on

britinusa
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Response Posted - 02/19/2009 : 20:37:17

Henk, how far 'down' could you lower the mast with the pop top up? I'm guessing that it would not reach the mast crutch.

Paul

Edited by - on

zeil
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Response Posted - 02/19/2009 : 21:59:05

Paul... the debate at home continues...

did we or did we not leave it up. In the picture the pillow placed on top of the pop-top would indicate the initial intention to lower the mast, if required, onto the pop-top but... did we manage to lower the mast and leave the pop-top in place...? We're not sure at this point...

Edited by - on

Arlyn Stewart
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2980 Posts

Response Posted - 02/20/2009 : 07:20:55

Henk, an alternative to using the forestay to gin pole connection for mast raising, the jib halyard can be used to the gin pole. Just be sure not to cleat the jib halyard in the cam cleats but rather make it to a horn cleat on the mast.

That way no transition of the forestay from the gin pole to the stem fitting needs to be made, the forestay is free to pin to the stem fitting while still tensioning the gin pole via the jib halyard.

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Arlyn Stewart
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Response Posted - 02/20/2009 : 07:38:01

James... I think they are correct in calling the pole a gin pole. In my view, any monolithic pole with a line at some point along the pole either fixed or sheaved to effect leveraging or lifting is a gin pole.

If the pole were not monolithic and were built of trussed parts, it might then be called a gantry pole.

Edited by - on

Tradewind
Admiral

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531 Posts

Response Posted - 02/20/2009 : 08:01:28

How long should the gin pole be and how is it attached to the mast?

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britinusa
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Response Posted - 02/20/2009 : 09:10:57

I was trying to find my much earlier post on doing this on the water, didn't find it.

Here's the way that I'm setting up JD to raise/lower the mast on the water.

I have a sturdy whisker pole (Telescoping 2" outside diameter, 7' long collapsed)

I also have my old lower shrouds that I replaced last year.

My intent is to modify the old shrouds to make new 'babystays' that will attach between the end of the whisker pole and the stancions where the mast's baby stays attach. I'll put pelican hooks on the lower end, and wire thimbles on the upper end of the new baby stays.

The upper end of the 'whisker pole stays' will attach with D shackles to the top of the whisker pole (somehow !)

Then I'll make a cup holder for the lower end of the whisker pole that will also hug the lower end of the mast.

Then I'll attach the spare gib halyard (unused as we have a furler) to the top of the whisker pole and secure the other end on the cleat on the mast (with a couple of turns around the mast)

Now all that will be necessary is to attach a line from the whisker pole down to a block near the stem and run it back to the winch.

I'll have to work out the lengths of lines involved, but I hope I can set it up so that there's at least a 2 to 1 advantage (extra blocks) so that not all the tension is on the winch.

It's a work in progress. The admiral is not keen on doing this, so I'll have to practice it in the backyard a few times before showing her the process.

Paul

Edited by - on

zeil
Master Marine Consultant

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Response Posted - 02/20/2009 : 12:37:53

Thank you Arlyn for suggesting to use the jib halyard instead of the forestay... why did I not think of that

. It'll also be very helpful and far safer, to keep the tension on the mast while pinning and turn-buckling the forestay.

Although I do not have the exact measurement the gin pole must be close to or just over 8 ft long. In horizontal position it reaches from the mast to just shy of the block & tackle eye in the anchor locker

In order to stow the aluminum gin pole below we cut the gin pole in half and used a 12" stainless steel sleeve over the joint

Edited by - on

zeil
Master Marine Consultant

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Response Posted - 02/20/2009 : 13:18:14

The mast end of the gin pole is equipped with a cup-type plate similar to the contour of the mast and comes complete with a two diameter pin which fits snugly into the bottom of the mast to prevent shifting.

Paul... your question... did we or did we not have to remove the pop-top to lower the mast. After some

we finally came to a consensus that in order to lower, un-step and run the mast to the foreward bow cradle it was necessary to lower the pop-top first.

Edited by - on

britinusa
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Response Posted - 02/20/2009 : 14:03:31

Henk, any chance of a pic of your gin pole cup?

Paul

Edited by - on

jbkayaker
Captain

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299 Posts

Response Posted - 02/20/2009 : 15:14:11

If you need dimensions to help with your shroud to baby stay conversion I can email some pictures of the ones Catalina Yachts Parts Dept. supplied for my 1999 Catalina 250 with a tape measure lined up next to them. Basically it is 81.75 inches between the two bearing surfaces with the pelican hook adjustment being able to loosen about another 0.25 inches or tighten a good bit more.

I don't know how to attach pictures here.

Edited by - jbkayaker on 02/20/2009 15:21:20

zeil
Master Marine Consultant

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Response Posted - 02/20/2009 : 18:25:40

'95 C250 WB Gin-pole to mast connection detail... at one point the wider part of the pin was welded and part of the the gin-pole mast cup. However, it cracked and broke off during a mast raising/lowering episode. (It is nearly impossible to keep the 8ft plus long gin-pole, once inserted into the mast, exactly aligned. This creates lots of stress on the weld). To prevent this from happening again and to allow for some up/down/sideways "play", at the mast we fabricated a steel pin insert which now is attached to the pin connection that is inserted into the mast. Since the long skinny part is inserted into the larger diameter gin-pole there is sufficient play without breaking anything and without danger to ever disengage...

To clarify... the long skinny part is inserted into the larger diameter gin pole with the thick part fitting into the mast. The short thinner stub protrudes from the back of the mast... To prevent alum to alum rubbing we recommend to include a felt pad to the gin-pole's mast cup.

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britinusa
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Response Posted - 02/20/2009 : 18:28:11

James, I think those numbers are correct, we have our original baby stays (we use them every trip)

I was thinking of making the 'cup' from PVC piping connectors. Hence my interest in Henks design.

Thanks.

Paul

Edited by - on

zeil
Master Marine Consultant

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Canada
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Response Posted - 02/20/2009 : 18:35:55

Paul... reading your last comments, due to the stress placed on the gin-pole parts during mast raising and lowering, I would hesitate to use anything else but the strongest materials & connections...

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