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.