Raising a junk mast

[AntarcticPilot]

Of course, getting a new mast in by the old was an evolution practised in the sailing navy! And they were keel stepped masts. Might just be worth looking at an old seamanship manual such as Darcy Lever's "The Young Sea Officer's Sheet Anchor" for ideas! It's available in facsimile from Amazon.

 

[Refueler]

The lifting point of the mast needs to more than 50% of its length regardless of its taper / weight distribution ... why ?

When its lifted - the mast will take on a 'balance' angle that if the lift point is only a little past 50% point - will make it hard to push base down to slot into mast point. The higher you can get the lift point - the easier that push becomes.

Personally - I would not use a crosstree .. I would stick to A frame where heads of verticals come together ... there's good reason that sailors for centuries have done that. It automatically gives lateral control of the frame .... folds down easily .... is stronger to mount the lift tackle and its centred ...

The size of the wood that can do this job actually is a lot less than first imagined ... due to the job being compression of length of wood rather than across causing breakage. Of course if using lightest bare minimum sized - care must be taken not to allow any movement of frame from vertical.

 

[AntarcticPilot]

The lifting point of the mast needs to more than 50% of its length regardless of its taper / weight distribution ... why ?

When its lifted - the mast will take on a 'balance' angle that if the lift point is only a little past 50% point - will make it hard to push base down to slot into mast point. The higher you can get the lift point - the easier that push becomes.

Personally - I would not use a crosstree .. I would stick to A frame where heads of verticals come together ... there's good reason that sailors for centuries have done that. It automatically gives lateral control of the frame .... folds down easily .... is stronger to mount the lift tackle and its centred ...

The size of the wood that can do this job actually is a lot less than first imagined ... due to the job being compression of length of wood rather than across causing breakage. Of course if using lightest bare minimum sized - care must be taken not to allow any movement of frame from vertical.

I agree that an A frame with two spars lashed together at the top will be both stronger and more stable than any arrangement using a cross bar. I think the only caveat I have is that the spars must be straight; if they bow it will weaken them considerably.

 

[andsarkit]

I agree that an A frame with two spars lashed together at the top will be both stronger and more stable than any arrangement using a cross bar. I think the only caveat I have is that the spars must be straight; if they bow it will weaken them considerably.

Completely agree that an A frame is better but I had rigid 90deg scaffold clamps to hand. The A frame would be a bit narrow at the top and I was not sure I would have enough clearance for the lifting loop and pulleys. As it turned out it was fine so next time I might put a bolt through the two poles and try an A frame.

 

[Refueler]

On the subject of HIAB ..... the latter end of this video illustrates my point ...

The boat alongside - is to lift and move the mast so foot is in line with deck fitting ... bolt in and ready to raise ... boat then turned bow to bank and HIAB + winch raises mast by it base pivot .... you see my mate just releasing the winch cable from the halyard.

 

[AntarcticPilot]

Completely agree that an A frame is better but I had rigid 90deg scaffold clamps to hand. The A frame would be a bit narrow at the top and I was not sure I would have enough clearance for the lifting loop and pulleys. As it turned out it was fine so next time I might put a bolt through the two poles and try an A frame.

Because I devoured Ashley's Book of Knots as a teenager, I tend to think in terms of lashings rather than mechanical fasteners

My skills in that line came in handy on a team building course where we were shown a pile of poles and rope and told to build a structure that would raise the whole team off the ground! Forget the team - I just got on with it, and the rest fetched and carried!

 

[Wansworth]

If it’s not already mentioned the Junk Right Association will have several ideas

 

[Ribtecer]

Am I the only one here that thinks it a shame to butcher a Hunter Medina?

Lovely little boats that sail really well.

Are there not other more deserving tubs worthy of such an experiment?

I totally get that it is your boat to do what you will with, but i feel for the poor thing.

 

[DownWest]

Am I the only one here that thinks it a shame to butcher a Hunter Medina?

Lovely little boats that sail really well.

Are there not other more deserving tubs worthy of such an experiment?

I totally get that it is your boat to do what you will with, but i feel for the poor thing.

You might remember that Hasler 'butchered' a Folkboat... It became rather famous.

 

[Wansworth]

You might remember that Hasler 'butchered' a Folkboat... It became rather famous.

And he also sailed a Kingfisher 22 junk rigged!

 

[DownWest]

The lifting point of the mast needs to more than 50% of its length regardless of its taper / weight distribution ... why ?

When its lifted - the mast will take on a 'balance' angle that if the lift point is only a little past 50% point - will make it hard to push base down to slot into mast point. The higher you can get the lift point - the easier that push becomes.

I don't get your first point?
I just checked my mast. It is 7mtrs long and the C of G is at 3mt from the foot. So, a little more than that, but less than 'over 50%' of it's length, will be OK . It weighs 23kg. Laminated doug fir.
Effectively supporting it from a point on it's forward side will not make it unwieldy enough to hinder.
The A frame of 25mm alloy tube will easily cope with that, just needs to be slightly longer than I first thought at 3mt.

The mast will be picked up from the deck by the A frame, then the foot pulled back and lowered into the space for it. Some guides will put the foot into it's socket, as it goes down, then it will be pushed forward into the slot in the foredeck and held by a cross pin. (bit of 25mm ss tube)

This needs to be easy, as it will be used most times I go sailing. I do have a free pontoon mooring up an esturary nearby, but I prefere the coast at assorted slips.

Slightly unlike the OPs 'hole in the deck and socket on the keel', but not too far different. And, I am assuming he will not be stepping it very often?

 

[Wansworth]

The secretary of the junk rig association had a 26 footer the name escapes me but Itwas that yacht that could have big outboards on the transome……anyway his junk rigged mast was in tow parts .Althoughkeel stepped the bit stepped on the keel hinged the rest of the mast about four foot above the deck so the top bit was lowered disconnected from the lower it and that was drawn out.Memory abit weak but I recall helping him stowing his boat on his trailer ,he went to many meets of the j r a

 

[Refueler]

I don't get your first point?
I just checked my mast. It is 7mtrs long and the C of G is at 3mt from the foot. So, a little more than that, but less than 'over 50%' of it's length, will be OK . It weighs 23kg. Laminated doug fir.
Effectively supporting it from a point on it's forward side will not make it unwieldy enough to hinder.
The A frame of 25mm alloy tube will easily cope with that, just needs to be slightly longer than I first thought at 3mt.

The mast will be picked up from the deck by the A frame, then the foot pulled back and lowered into the space for it. Some guides will put the foot into it's socket, as it goes down, then it will be pushed forward into the slot in the foredeck and held by a cross pin. (bit of 25mm ss tube)

This needs to be easy, as it will be used most times I go sailing. I do have a free pontoon mooring up an esturary nearby, but I prefere the coast at assorted slips.

Slightly unlike the OPs 'hole in the deck and socket on the keel', but not too far different. And, I am assuming he will not be stepping it very often?

Even when a mast or beam is lightweight - when you try to push base of it so that it becomes vertical - it gets harder as you approach vertical .. and if you don't lift high enough ABOVE the 50% mark - believe me - it can get hard to get it vertical. Its a bit like the old trick of piece of paper halfway along a piece of string and trying to get it absolutely sdtraight horizontal. The more you pull to straighten - the harder it gets .. but move the paper nearer one end and the string straightens more.

7mtrs long and 23kg ?? Interesting .... I have 6mtr long PAR pine of 10 x 15cm (I have various wood for renovating my old pontoons) ... one person can lift it - but takes two people to handle.

 

[DownWest]

Just to add to this. Musing on mast lifting early one morning... My main sprit boom is 4.5 mtr. So, going to set up a socket and clamp next to the mast and use it as a crane. No extra bits, like an A frame. It's length gives me 50cm over the mast C pf G as a lift point. Should be enough.
I will post a photo when I get it sorted.

 

[LittleSister]

I have often pondered the challenge of mast raising when one doesn't have a tabernacle or A-frame.

I my more fanciful moments I mused about helium balloons attached to the top of the mast to take most of its weight, but then realised that the weight of the mast is probably more than the tanks that helium comes in. (Perhaps instead of helium, could one use hydrogen separated out from the water the boat is lfloated in?)

I also wondered how big hot air balloons would need to be for the task - probably rather large! One would also need a means of generating the hot air (maybe this forum could help? ) and getting it into the bags.

With either helium/hydrogen or hot air one would need a method of detaching the bags from the top of the mast after raising it, and re-attaching them up there to get it down again.

Perhaps I could make my first million building and renting out a four-rotor drone powerful enough to lift masts?

 

[PatrickB]

Arctic Pilot's approach, using an A frame, is exactly how we did it on my son's junk rig boat (since sold) - mind you there were two of us, I don't think I could have done it single handed.

 

[Blueboatman]

Hello all and Seasons greetings.
I am part way through a design to convert my 20' Hunter Medina to a junk rig. Looking for some ideas to step the mast. It will be approx 8m tall, round in section and weigh approx 30kg. It will go down a hole in the deck 1.2m to the base in the hull. I haven't yet decided whether to have partners at deck level and a separate mast base or whether to slip it in to a fixed in place tube.
My current mast is easy. It has a hinge on the deck and I raise it with an A frame. The new mast has no supports, no rigging, no hinge. It will be smooth, with no spreaders. It will be in three tubular sections, one inside the other, so I was thinking maybe some sort of telescopic arrangement. Or perhaps some sort of hinge and slide arrangement.
I don't have any boaty friends here so I can't do it alongside another boat. There's nowhere high enough and accessible, like a bridge or gantry at the launch site. I really need to do this single handed.
Any ideas would be gratefully received.

Firstly, good luck with your conversion. May I suggest that you hang on to the original rig as well in case one day yiu decide to sell or indeed convert back to original ?
Now to your specific question
As a former junk rig user, I’ve raise the mast three ways
Firstly the plain and daft. Just pick it up and balance it precariously and feed it down the hole. I got away with it. Young, fit and strong
Secondly and infinitely the easiest . Bring the boat alongside a wall or quay at low water, put a person, water containers or anchor and chain on the side deck in order to heel the hull toward the quay, then simply feed the mast over the edge of the quay ( on a piece of cardboard or carpet so as not to scuff it up) and slide it home into the hull.
Thirdly , I have raised the mast afloat and that was interesting but can definitely be done: You rig up an A frame using the yard for the sail, which is a strong item, and a bundle of weaker sail battens, secure these port and starboard and vertical to meet somewhere just ahead of the mast partner hole in the deck, then using a block hook the mast upright and ease it down into its hole. Yiu won’t have enough length of yard/ sail battens to be able to tie onto the mast above its centre of gravity, but you won’t need to if yiu have a helper or are strong and competent enough to keep control of the rope and the masts foot and ease it down into its hole..

Good luck, it’s ( mostly) a great rig and on your size of boat I travelled many happy trouble free miles.