Mast lowering.

[firstascent2002]

Have just put a deposit down on an RM trailer and am bringing my old girl home for the next year to dry out and give her a face lift so I may need a fair bit of help over the next year or so!!.

First problem mast lowering.

The plan is to lash the boom acros the tabernackle mount of the mast, and take a rope from each end of it up on the jib halyard. I'm hoping this should elimate too much lateral movement.

Next to run a rope from the end of the inner forstay through the spinnaker pole and down through the bow roller. Spinnaker pole should be made fast to boom as well I guess. Then lower away. mast goes down ans spinnaker ople goes up. what could be easier...

Am i missing anything important?

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[AndCur]

Two poeple can easily lower my achilles mast with out any problems. We simply use a large pole with a y shaped section at the top to support the mast when its on its way down we also rig a rope to a pulley system to the jib halyard to give more control to mast on the way down. This system is used in our club for most of the boats with out many problems.

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[snowleopard]

in the setup you describe you need two lots of additional bracing:

the spinaker pole needs to be braced sideways or it will fall to one side as the mast approaches the horizontal. more importantly the ends of the boom must be secured to prevent them moving up or forwards. the boom must be as close to the pivot point as possible to keep the staying length constant.

bear in mind that the load increases dramatically as the mast approaches horizontal so make sure you have adequate braking on the halyard or it could run away with you.

as a rough approximation the force you have to contend with is:

weight of mast x height of mast x 0.7
------------------------------------------
length of pole

and masts are generally a lot heavier than you'd expect.

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[bob26]

You are talking about a Seal 22 mast?

Personally I'd rather make an A frame out of the spars you have, with the base anchored on the deck each side of the mast with the apex at the bows. With one person lowering the other should be able to control sideways movement if the mast is in a tabernacle.. You need some sort of crutch well aft to take the weight when it is near horizontal and much of the mast is sticking out over the transom. That's when a Y-ended prop comes in useful because the mast is generally too high to reach from the ground and the overhang puts a lot of pressure on the bloke at the back.



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[Jools_of_Top_Cat]

My dad and I did this on the beach at Porthmadog years ago when I was still very strong and fit. He was able to stand well back from the stern with warps passed over a strut on the transom, the warps had about 3 turns so he was just expecting to brake the fall. My job was to walk the mast down the coachroof, the side stays loosened right off but not removed to give extra support.

I cannot remember the strut, but it should have worked, it did in the area that it did not break, and it did assist in braking the mast. The mast is 30ft.

All was going well until the mast passed about 45°, then it got heavy, very bloody heavy. My dad 14st was dug in to the beach like the anchor in a tug of war but was being pulled towards the transom, I am shouting out loud, a wieght lifting type grunt trying to now take the wieght rather than just act as a steadier. The mast came down, a controlled fall if you like, it did not drop and done what we inteneded.........but, never again, the turning moment was just too much. I am still surprised the foot did not give way under the pressure.

No help, but just consider all outcomes carefully, counterwieghting might be an option rather than relying on brute force, you have heard about the builder and the barrel of bricks haven't you?

<hr width=100% size=1>Julian

<A target="_blank" HREF=http://www.topcatsail.co.uk>Top Cat Homepage</A>

 

[Seal_surfer]

I have a seal 22 and have been raising and lowering mast every season for last 7 years, but practise had made it near perfect - eventually! Allow plenty of time (2 to 4 hours), double check at each stage as its easy to do expensive damage if you're not concentrating.

It can be done single handed, but is best 2 handed. Don't underestimate the weight once its below 45 deg. If you rely purely on the stemhead line/tackle or winch it puts huge compression and twisting strain on the mast foot/heel plug casting where it is fastened into the mast extrusion. This is because the pivot point is not directly under the mast, but at the aft end of the casting. This can cause the casting to break tthe securing screws or rivets and slip out of the mast extrusion in mid operation - very risky!

To avoid this, assist the mast by making a simple 8' long or more crutch/clothes prop to jam under the spreader bracket once mast is low enough to reach. This takes much of the weight until it is low enough to reach up and manually assist it down on to scissor crutches. This all assumes your Seal hasn't had a custom Tabernacle fitted, but crutch prop would still be advisable.

I made up some steel triangle frames that engage on chain plates and position a temporary shroud anchorage in line with mast pivot axis athwartshup to control lateral movement. Leave cap shrouds connected but watch out for any snagging - shrouds often catches on wooden hatch surround near cockpit.

I used to use coachroof winch but evolved to fitting main sheet tackle/jammer to stemhead and pole end.

A final refinement was to make up a stern roller that uses a trailer roller for the mast to drop on so that it clears coachroof and hatch coaming whilst the pivot pin is removed, then mast rolled f'wd with roller supporting overhanging section. This consists in a cross shaped tubular steel frame that drops over rudder pintle and has hooks that go over pushpit rail.

Good luck.

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[William_H]

Depending on whether the boat is on the water or the trailer in my opinion the sideways movement of the mast is not so much concern especially if you can assign a person to steady the mast while standing on the cabin top. If you are on the water you need to haver still conditions and drop the mast fairly quickly into a supporting crutch.
If you are concerned about sideways support you can use a main and jib halliard one either side attached near the gunwhale abeam the mast step, continuously adjusted to support the mst in it's swing down.
An alternative is to attach buldog clamps to the side stays in line with the mast pivot and brace these points foreward so that the stays remain tight in the traverse down.
You can use a single pole from the base of the mast foreward to the forestay bow fitting but this must be braced sideways and two poles pivotting near the gunwhale approx abeam the mst is a better arrangement. You can use an inner forestay or even a jib halliard but I think the main forestay is the most robust . If you use the inner forestay the loads will be much higher because you are lifting from the centre rather than the top using forestay. You will need at least 3 purchase tackle to the forestay and this should then lead to a winch to provide control as the mast goes lower than 45 degrees. You must have a crutch at the transome as high as possible as this will take the load earlier in the descent.. I like to disconnect the mast pivot and get one person (tall) to help slide the mast foreward in the crutch while another guides the base of the mast until it is at the pulpit and the top of the mast is near the crutch top. It will then be easy to lower the top of the mast down to ideally a shorter crutch for towing.
I lower my 9 metre tapered fractional rig mast while under way approaching bridges and it is a worry but not unduly so.
If you can get someone standing on a step ladder or jetty so that thdey can catch the top of the mast that is so much easier. It is worth investing in strong stable gear as I reckon you will be lowering the mast a lot when you find how easy it can be.

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[MIKE_MCKIE]

If there is anyone you know that has a Macgregor 26 get them to show you the mast lowering instructions that come with the boat. A pal of mine had one & first time he loaned me the boat I rigged the mast from scratch single handed (albeit on the trailer ashore), simply by doing what it said on the tin. Likewise lowering at the end of the day. A fair bit of planning & effort, but it worked & was safe. It does use a prop spar forward to keep the forestay up & increase the angle of the forestay when the mast is low, but the spar does not require side stays, simple geometry keeps it vertical, provided the mast is fore & aft.
Best of luck, remember the 6 P's, Perfect Planning Prevents Piss Poor Performance, & you won't go far wrong. I am told it this is also applicable to other areas, but have so far failed to prove it's efficacy!
Brgds
Mike

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[extravert]

Alternative method (pic)

Does your mast heel deck fitting allow you to lower forwards rather than aft? Mine goes down forwards, which has these advantages...

If anything goes wrong and it falls down, it falls where people are not, rather than crashing into the cockpit.

You can use the boom as the perpendicular beam, which is already in place and strongly attached.

You can take two lowering lines from the end of the boom to the toe rails and then to winches. These provide sideways support to the boom as well as controlling the lowering.

You will still need to make up some lines to support the mast sideways as you suggest.

Here's my boat's system in action.

<hr width=100% size=1>One day, I hope to own a real boat.

 

[firstascent2002]

Re: Alternative method (pic)

Great photo!!. Sadly can't lower forwards but thanks anyway.

appreciate all the advise, new trailer will be arriving in 5 weeks and I want the mast down by then so if the wind abates than I'll be giving it a try. Seal_surfer, I've Pmed you re the metal triabgles that you mention in your post.

Thanks one and all

Jamie

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[Gunfleet]

Re: Alternative method (pic)

It doesn't matter whether you can lower forwards or not, extravert's just shown you the right way to do it, that is with a spar at 90 deg to the mast so that you never end up trying to hold the mast on whatever purchase you have at an obtuse angle. The obtuse angle is what Jools was describing and I've made the same mistake. It was awful. However with a nice big spinnaker pole close to the J mmeasurement and lashed at 90 deg forward from your mast and a 6-1 purchase rigged from the end of that pole to the stem head while either the forestay or jib halyard goes from the top of the mast to the end of the pole too, you only have to control the descent through 90 degrees. A chum on the foredeck can control the side to side movement if you want but the Dutch (who do this a lot, for obvious reasons) often have a stainless A frame permanently rigged to the bottom of the shrouds. This is usually stowed along the deck towards the stem. In use it is fixed to the mast and controls lateral movement while a spar and 6 part purchase deal with the fall. If you feel it's dangerous you're doing it wrong.

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[Avocet]

Re: Alternative method (pic)

I've lowered a 30' mast with 3 people a few times. It helps to have a very long rope on the end of the forestay, someone to hold the mast to stop it moving sideways and someone in the cockpit with an extending ladder to catch the mast. If you get the height of the ladder about right, it catches the mast just in the region of the spreaders and long before it gets to such a shallow angle that it all goes pear-shaped. Once this has been accomplished, you can take a breather and all three people can go to the ladder. This can then be lowered a rung at a time until the mast is low enough for someone to hold it standing on the transom. The ladder can then be moved out of the cockpit and down on to the ground where the process can be repeated in easy stages.

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[extravert]

Re: Alternative method (pic)

I used to do something similar to what you suggest with my 30' mast on my Extravert, and had a few scary moments. Although with a mast this size and plenty of helpers, it is possible to get away (just) with using people to hold the mast and perpendicular strut to stop them moving sideways, it is a lot easier and safer if some purpose built system can be devised that does this instead.

My mast now is 45', and definitely needs a proper system of support while lowering and raising. It makes it safe, and also makes it a two handed job. The equipment I use is all manufacturer supplied, so it is all fit for the job and works well, but making a similar home made kit should not be difficult or expensive.

<hr width=100% size=1>One day, I hope to own a real boat.