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Jib sheet turning block location

PostPosted: Fri Feb 25, 2011 7:07 pm
by Clyde
My DS1 has no turning blocks for the jib sheets. What type of block would anyone recommend and where should it be located - i.e. how far back along the side deck or gunwale?

Any suggestions would be appreciated.

PostPosted: Fri Feb 25, 2011 8:09 pm
by GreenLake
The typical thing would be to mount a set of 12" tracks such that the forward position is about 6-9" from the cuddy opening, see the picture. (click to get a larger view).


As you can see, I got a Harken part (track and sliding car with block) but you might find different or cheaper makes.

The correct placement depends a bit on the cut of your sail, the idea is that in different wind conditions you want to be able to have the angle at which the jib sheet pulls such that the luff of the jib "breaks" evenly top to bottom as you come up into the wind.

Mine seems to give a reasonable range of adjustement.

PostPosted: Sat Feb 26, 2011 9:20 pm
by K.C. Walker
In addition to what Green Lake mentioned and pictured I have added an auto ratchet block and really like that. A ratchet block will give you somewhere between 5:1 and 10:1 holding power after you haul the in the sheet line. This makes it a lot more comfortable to hold on higher wind days but also allows using the cam cleats under less tension and therefore it is easier to cleat and uncleat.

Backing place

PostPosted: Mon Feb 28, 2011 3:03 pm
by holstein

Were you able to install a backing plate behind the track ??

I'm interested in doing something similar, however on my DS I do not have access the the space behind the wood trim.

I was considering installing the track on the rail where the hull and deck meet. (behind the shroud u-bolts )

Bill H

PostPosted: Mon Feb 28, 2011 3:28 pm
by Mike Gillum
I installed the same Harken track in the same location in #2772 which is where the original track was installed.
There's a piece of wood moulded into the deck reinforcing the deck where the original track was installed.
No need for additional reinforcements just make sur ethe original holes if you use them don't have any dry rot.
Like K.C. Walker I used a Harken 40mm Carbo Ratchet Block on the track to help my crew with sheeting the Jib.

PostPosted: Mon Feb 28, 2011 9:19 pm
by GreenLake
Dry rot is a concern. The way the wooden carlins are glassed in does a good job of trapping moisture and a poor job of sealing.

On my boat, there seem to be some spots that are a bit soft, right around the screw holes. As a temporary measure I treated them with epoxy. That stiffened things back up to where the coaming and jib track screws will hold firmly again.

When I got the boat, on the maiden voyage, so to speak, the screws for the jib track pulled out on the water - the P.O. had refinished the coamings and that had loosened the screw holes in the wood. That's when I installed my new jib tracks.

The best epoxy for this purpose is something that flows easily and gets wicked as far as possible into the wood. SystemThree makes a product called RotFix, which is a very low viscosity epoxy that flows like water. There are competing products that use strong solvents to achieve the same effect (these are usually called 'penetrating epoxies').

If have some good laminating epoxy, you might be able to use that as well. It wouldn't wick in as far, but should work much better than any epoxy that's formulated as a glue.

Epoxies have an extensive shelf life, by the way, so any leftovers can be kept around for future projects.

PostPosted: Mon Feb 28, 2011 11:25 pm
by algonquin
Epoxy - The modern sailors duct tape !! :lol:

PostPosted: Mon Feb 28, 2011 11:50 pm
by GreenLake
I admit, I tend to think of it first. It does have some limitations. (Here's not the place to elaborate, because we are discussing jib tracks).

Wood strength

PostPosted: Tue Mar 01, 2011 12:39 am
by holstein
My jib sheet currently cleats off on a set of swivel cam cleats on the cabin top.

The wood trim around my cockpit is only about 1/4 in thick and 3 inches wide. I think it is more for cosmetics and to hide the hull to deck joint.
I'm concerned that it is not structurally robust enough to handle the jib track.

Have you seen any DS's with this configuration ?

Bill H

PostPosted: Tue Mar 01, 2011 3:21 am
by GreenLake

this would be easier if you uploaded a photo. My DS is a '63 and by looking back at your first posts in this forum I'm reminded that yours is an '86. I see from the bylaws that the coamings on your boat are not structural. However, even on my boat, it's not the coamings that hold the jib track, but the carlins. Those are pieces of wood that are encased in fiberglass along the deck edge. My DS doesn't have a double hull, so I can reach under the coamings and see those (somewhat sloppily) encased wood pieces.

In your case, the place where the coamings are fixed to may or may not have additional support behind the fiberglass. That's something I don't know. Perhaps another owner of a 'recent' DS1 could provide some input.

The general technique in your case would probably be to cut some inspection port somewhere, so you can get access to the area between your hulls in the right place (and mount any missing reinforcements).

When I say that the coamings on my DS are structural, I mean that they are stiff in the vertical dimension. They are also only 1/4" thick, but by their placement, they resist flexing of the deck in the down/upward direction (important if you are sitting on those decks when hiking).

Similar setup

PostPosted: Tue Mar 01, 2011 6:20 pm
by holstein
I'll try to post some photos tonight, but I found a similar layout in the board.


Bill H

PostPosted: Tue Mar 01, 2011 7:07 pm
by GreenLake
How are the coaming strips fastened? Screws? If so, are they just screwed into a normal layer of fiberglass or is there something more substantial that the screws go into?

I'd think, unless you hear from anyone who has a double hulled DS1 like you do, you have essentially two options.

One, is to add an inspection port right below where you want to add your fitting. That should allow you to reach the space and add a backing plate. (If it's foam filled space, then you may need to remove some to be able to reach in).

The other would be to use something like a wall anchor, if that's the correct name. You know, one of those things that you push into a hole and that expand and can distribute the load. I seem to recall a conversation at the dock, recently, with someone who has a different small boat, one of those that are essentially not that different from a surfboard with cockpit. He was describing how he added some fixtures with "blind" fasteners where he couldn't add a backing plate.

That's all I can think of right now.