Mast and sail


Sept 13th 2015

Mast is going to be a hollow birdmouth mast, length about 6m or 20ft, diameter 120mm or 4 23/32inches, tapered towards ends.

This is how I ripped all my wood, very simple setup on handheld circular saw
A piece of plywood screwed to it to act as a fence, working on 2 chairs... Joining strips to get desired length, so that all joints are on different heigth when mast glued together; planing, then cutting the birdmouth and tapering...

Here setup on the saw for cutting birdmouth.
 Just tilting the saw 45 degrees, screwing on piece of scrap plywood for fence, and... with a helping hand: saw one foot forward; one foot back saw together with the strip; and so on.
 here the mast top side of the strip before and after tapering


Dry fit and assembling

Quite a bit of mixing thickened epoxy. Had 10 hose clamps, clamped on  cilindrical area first, fixed with packaging tape and moved towards ends, reclamping hose clamps and fixing with tape on the way. Using C-clamps ocasionally to squeeze out epoxy
 

Sept 16th 2015
From this shape planed it octagonal first, then 16 sided. But The lines were not clearly visible; to change that, I stained it first and then planed the corners off again, trying to get the stripes as equal width as possible


Then continued to plane it round

The blue hose that sticks out is a hose running through the mast for masthead light wires.

Oct 3rd 2015

The mast is now sanded, by a classic round mast sanding setup
The drum on the drill should have larger diameter than mast, to have enough resistance to make the belt move. in my case I just pressed on the belt with a thumb and controlled belt tension. The heel I made from 8-sided back to 4-sided. I left the end plugs sticking out, for supporting the mast while painting it later

 I milled a groove in the front of the mast and fitted a flattened copper tube for lightening rod

Then the mast was epoxy sealed and will probably wait to be painted until spring next year



May 10th 2016

I planned to make the sail during winter time, but as I was working away from home; it didn't work out that way... So when at home, the weather was not as warm yet, so I decided to deal with sail first. I ordered some Odyssey fabric for sailcloth; took an old sewing machine back to the shop and came back home with a new one; got some thread from a guy near by and I was ready to start.
First (whilst waiting for the fabric to arrive) I made templates for each batten panel; 6 in total, 4 templates as 3 lower panels are the same. The design was worked out long ago, with help from JunkRigAssociation; and specially from Arne Kverneland. The sailmaking way also follows Arne's description of his own sailmakings and suggestions. 

It is a cambered sail, with 8% of camber calculated into it. Battens and boom will be 30x2mm aluminium alloy tubes; and the yard 50x2mm tube; purchasing of these is still pending; hard to get the right alloy in this country...

I taped the fabric to the floor; then fixed a template to the cloth with tape again and marked the outline of template. then marked several points for (curved) hem lines and used the template to conjoin these points.
 
The panels have a round on top and bottom edge, an extra space for making the camber. Upper panels have smaller round.


Placed the upper panel on top of the lower, upside down; lined it with the 15mm line. Folded the lower panel hem back, on top of the upper panel, at the 15mm line; then folded it once again at the cutting edge. Each time it had a tape to hold it in place (in different place on every fold); then folded the upper panel over the seem and voila – ready to be sewed. Tape held it together well.  

 then 2 batten pockets on top of each seam. Space in the middle for batten parrels and Hong Kong parrels. The forward one, the one against the mast, is made of the PVC coated cloth, similar to one that the truck tents are made of, for wear resistance; the one towards leech is from the sailcloth. 
 

Section of the seam looks somewhat like this:
(source: http://www.junkrigassociation.org/Resources/Documents/Arne%20Kverneland's%20files/1%20The%20Cambered%20junk%20sail%20,%20ver%2020071228-1.pdf)



There were more easy sewing systems suggested by Arne, but I went for a complicated one. Each new panel had to be rolled together to get it through the sewing machine; also folding was more complicated. But doable for a small sail like mine. After sewing all 6 panels together, I laid it on the grass outside, to see if the shape is some what similar to the one on the drawing board ;) Not too far away.
 

Now there is left hemming and some sloops and hoops... As the weather is nice and that is a different job anyway; I use the weather to work on mast and hull and finish the sail when the weather is not as good.



May 29th 2016

The mast is now faired and primered



 

There will be more coming...

4 comments:

  1. I'm following your project carefully,
    But I didn't understand, when cutting the birdsmouth, what you meant by "one foot forward, one foot back . . ."?

    ReplyDelete
  2. Hi John,
    What I meant is... Had I used table saw for this, I would have had to just push it through; but as I was using handheld saw, I couldn't push the saw through the length of the strip, as the table and the side support, fixed to the table were not long enough; also considering that the strips hanging over the table were quite fragile/bendy. So instead we pushed the strip through from under the saw; but the resistance was too big for the strip to slide back on the table while having the saw pressed down against it. So instead I stood behind the table, pushing the saw as far forward as I could, then pulling the saw back, together with the strip :)

    Hope this is more clear now.

    Eerik

    ReplyDelete
  3. Thank you!
    I understand the problem!

    ReplyDelete