I’ve got my Marblehead hull faired and primed and it’s time to install the drum winch and sheeting system,etc.
I’ve got some diagrams in front of me of the various sheeting systems that can be used with a drum winch but there are two things that stump me.
I think that I would like to use a closed loop system but what parts would I use for the pulley system? Where would I get the ball bearing pulleys? (Note I mean large pulleys not blocks)
My foredeck is closed off already so I may go with an above deck sheeting system. Unless one of you guys know of an easy way to install under deck system. How did you do it?
Anyway, I’d rather not reinvent the wheel and wanted to see what you guys came up with and what parts you used to make it work.
The closed loop systems I have seen use pekabe or similar small blocks. I’m not sure why you would want to use a large pulley instead of a small block - sounds like it would just add extra weight. I’m guessing that the diagrams show a large pulley so that you can easily see what it is… I have not seen any marblehead systems, but on the US1Ms, IOMs and EC12s I have seen, they use the small blocks. Besides, I would be worried about the loop line jumping off an open pulley where it cannot do that with a block…
Rigging a system under the deck once it has been installed is difficult but not impossible. You can drill a small hole through your king plank at the position where you waht your forward pulley located. Then, you can pass a length of rigging line through that hole and feed it back until you can reach it throught the hatch. Pull it out and tie your forward block onto that. Then, you can just pull the rigging line back up through the hole and it will pull your block forward. To secure the block in that position, you can tie off the rigging line on the top of the deck near the hole. Make sure you put another length of rigging line for your closed loop system through the pulley before your pull it forward as you will not be able to get to the pulley later. You will need to position the aft pulley a little lower than this forward pulley so that you are not dragging your shuttle along the underside of your king plank. Also, you may need to position the aft pulley slightly off to the side so that the loop clears your keel trunk and mast compression strut (if you have one).
You may want to have the shuttle side length of the loop on one side of the boat and the other leg of the loop that passes around the servo drum on the other side so that they form a slight triangle. plan this out ahead of time as it may dictate how you rig the your loop line through the pulley before you pull it forward.
You do not need to have the loop line cut to length at this point. you will have access to both ends of that line after you have pulled the pulley forward, so you will be able to make all your adjustments after you have the other components installed…
Note, you can do the same trick with a small hole on the stem plank instead of the king plank. This hole could then get covered with a bumper…
I’ve got drawing here from the US 1Meter Construction manuel that shows a large pulley system that’s similar to the system that’s used on the “Skapel” M-class boat. I’ve alway known for some reason that large pulleys have less friction resistence than small pulleys. But it may be moot here.
Otherwise, That’s a neat trick! Using a piece of rigging line to pull your block forward.
I would have to agree with Will here; the main thing is to choose your pully or block in function of the sheetingline. If the pully or block is to big it will jump of, if it’s too small it will result in to much friction. I use 2 blocks and a closed sheetingloop myself. But then again I built a 10-rater so I have room to spare …
One extra thing, try to position the thru-deck-block (hope you know what I mean because I don’t know how to write it otherways in English) in the same virtual line of the sheeting system. It will provide the most power, the least friction and the least chance to pull it of the block.
Sorry, can’t help you with that. I use a Whirlwind Olympic Special. The Whirlwind has a little screw so you can adjust the travel to your own settings.
The standard HiTec sail winch has a travel distance of 450mm.
I use the endless sheet system on my multihull, and have a spring included in the loop to keep the tension.
I have had the drum mounted above the deck on previous boats. THe use of some silicone helps when mounting this way.