Wednesday, January 21, 2015
Getting Up In The World
Longtime readers of this blog will remember that Helena and I have already experimented with home-made bosuns chairs. It was so much fun that Helena insisted on giving it a go.
Home Made Bosun Chair photo jalmberg |
In the impossible case of the seat cracking, the crossed line would hold the thing together long enough to get the victim -- I mean worker -- down safely.
Add a 6x block and tackle, a safety harness attached around the mast, one halyard for the chair and another for the safety harness. Toss in a healthy dose of common sense and you are in business.
The big problem with this approach is the 6X block and tackle you need to hoist a full grown person. Even on my short-masted boat, this means threading 200 feet of line through 2 triple blocks. And you cant just thread the line any old way. Because of friction, the line has to follow a specific route through the sheaves that I cant remember without pulling out the books.
In short, the bosun chair is the best way to get to the masthead, but its an all day project. I wanted something simpler and quicker.
The inspiration for this project came from watching a fellow sailor climb to the top of his very tall mast on an ordinary household aluminum extension ladder. Well, duh! I thought. How simple is that.
That got me thinking of ladders, but I wanted something a little more portable. Something I could stow away down below in case of emergencies far from home and ladders. Then one day, I was thumbing through my "Ashley Book of Knots", and found exactly what I was looking for.
The solution was on the very last page of the book, in fact:
Rope Ladder from Ashley Book of Knots |
The ingredients for this project are:
- enough 1/2" line to go up and down the mast, with enough left over to tie securely. I started with 100 for my 27 mast, so I had plenty
- enough oak dowel stock to make the rungs. I bought 3 lengths of 1" round stock from Home Depot and cut them in half to make 18" rungs.
- tarred marline for the lashings. I used #18 tarred nylon since I have several miles of it lying around
- a thimble for the top.
The rope and dowel are probably oversized for strength, but you want something thick enough to hold on to. The 1/2" line and 1" rungs felt just right for my particular death grip.
I started by lashing the thimble into the middle of the line, then pre-marked the position of the 15 rungs on both parts of the ladder. To do this, you need to take as much of the stretch out of the line as possible. I tied the thimble to a work bench and stretched out the two parts on the floor, parallel to each other. Then I marked off the positions of the rungs, 18" apart, on both lines.
Laying the two lines out on the floor for marking... The stretch needs to be taken out of both lines evenly before marking. |
In retrospect, Id probably reduce the rung spacing a bit -- perhaps to 14" -- but 18" is fine.
Once the rungs were marked off, it was time to start lashing. I tried various ways to do this, but the easiest was to suspend the ladder from the ceiling and work on it standing up.
At this point, some you are probably saying, Whoa! Lashings?!?! NO WAY IM TRUSTING MY VALUABLE 200LB CARCASS TO SOME DANG LASHINGS!
The first couple rungs |
Some simple math will show its perfectly safe. #18 tarred nylon has a breaking strength of 170 lbs. If you put 10 turns in your lashings, as I did, the lashing should be good for 3400 lbs -- enough to hold even the loudest member at the yacht club bar. (Think about it... each turn is 2 strands... one on one side, and one on the other, so 20 strands all together.)
I forgot to take a picture of this, but to prevent the rung from rolling, I used a half-round rasp to cut a shallow, round notch in each end of the rung. The line is laid in this notch, and then the line and rung are lashed together with 10 good, tight turns.
Here are front and back photos of the lashings.
I forgot to take a picture of this, but to prevent the rung from rolling, I used a half-round rasp to cut a shallow, round notch in each end of the rung. The line is laid in this notch, and then the line and rung are lashed together with 10 good, tight turns.
Here are front and back photos of the lashings.
Back... you can sort of see how the line is recessed into the smooth, round notch |
Front. Notice how the lashings are crossed |
As a side note, I gave all the rungs several good rubbings with linseed oil before lashing them on. They dont really need much protection, but I like the smell and look of linseed oil.
After youve got a few rungs lashed on, it gets a bit unwieldy. I found it best to keep the part I was working on hanging as straight as possible, with the rest of it out of the way.
Plenty of light and a place to hang things is essential. Note the tape on both lines showing the rung positions |
Left side temporarily held by constrictor knot, while the other side is lashed |
By the time you are done, you will have perfected your lashing skills, and if you are like me, will be raring to try it out.
On a calm summer weekday (to minimize powerboat traffic), with Helena in the chase boat, and 911 programmed into speed dial on her cell phone, I proceeded to hoist my lovely ladder up the Blue Moons mast.
The ladder hoisted and steadied by bridle to bow |
First, I discovered you want the ladder to hang at a bit of angle from the mast. This makes it a lot easier and less scary to climb. Trust me.
Taking the stretch out of the ladder |
Then, to put even more tension on the ladder, and to prevent it from twisting, I lashed a kind of bridle to the ladder and tied the bridle off on the Sampson post in the bow. See the bridle in the two pictures above.
With these precautions in place, the ladder was stiff and easy to climb, even for an old geezer like me.
Getting that halyard back up again |
In the photo above you can see that the halyard has also stretched, so the head of the ladder is too far below the masthead. As you take the stretch out of the system, be sure to re-tighten the halyard so the head of the ladder ends up at the masthead. A lesson for next time...
And that was that! Now that I know how to rig it, the next time, it will take about 10 minutes to hoist and secure. Very salty looking and the envy of my yacht club.
>>> Next Episode: Mark III Block Update
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