DSII Mid-boom Sheeting

Moderator: GreenLake

DSII Mid-boom Sheeting

Postby TRWXXA » Sat Apr 10, 2021 10:59 am

Got a new boom, courtesy of Rudy, for my DSII.

BTW: Southwest Airlines Cargo is THE best way to ship a spar (up to 13.5'). Faster and cheaper than EVERYBODY else. You just have to go to the airport to pick it up.

The old boom was hacked beyond measure with spit and bailing wire -- literally... BAILING WIRE. Some people need to learn that Tractor Supply is NOT a substitute for a marine supply store. I don't like spending $40 on a Harken block either, but that $2, pig-iron pully will get someone hurt.

Back on topic... The boat has mid-boom sheeting, and the boom and boat are not in the same location. With eyeball and tape measure, I make the correct mounting point for the sheet block bail to be 72" from the back of the mast, or about 70.5" from the mast end of the extrusion itself. The old boom is useless to measure off of. Pretty sure it's off of another model boat with boom-end sheeting. Hence the hack job.

Before I put drill to boom, does this sound right? Does anyone have any official, O'Day measurements for this mounting?
I suppose it would be better to err on the longer side of placement. Maybe 73" or 74" from the mast?

Thanks!
Chris S.
DSII #10220 -- "Uisge Beatha"
TRWXXA
 
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Re: DSII Mid-boom Sheeting

Postby GreenLake » Sat Apr 10, 2021 1:58 pm

Class rules do not put any constraints on how you rig your mainsheet. Therefore, class rules can't give you that answer. To my understanding I wouldn't expect a difference in location of the mid-boom block whether it's the turning block for end-boom sheeting or the single attachment point for center boom sheeting. However, I've seen booms rigged with two single blocks, spaced out a bit along the boom, instead of a double block. In which case I'm not sure how those would be located.

I've never given the question much thought, because I've never made a change in that aspect of the rigging. Unfortunately, I'm also not able to access my boat for measurements.
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Re: DSII Mid-boom Sheeting

Postby TRWXXA » Sat Apr 10, 2021 8:41 pm

The old boom looks like it was end-sheeting only, with no mid-boom block. Like I said, I think it was for another sailboat, and the p.o. tore it up trying to make it work on a DS with hardware store parts. The pully (I'm not calling it a block) was wired to a cleat on the side of the boom, which is nowhere near the right location. It's useless as a guide for outfitting the new spar.
Chris S.
DSII #10220 -- "Uisge Beatha"
TRWXXA
 
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Re: DSII Mid-boom Sheeting

Postby GreenLake » Sun Apr 11, 2021 1:14 pm

I get you on the problem of not having a pattern.

Intuitively, I would think the block location should be directly above the block in the cockpit.

However, at the moment I'm not where I can get you a measurement for that for my boat. I'll be happy to take one for you when I'm able to, but perhaps someone else reading this can beat me to it.

PS: on naming: the reason we call these things "block" is that they started out being just that: blocks of wood, with no sheaves. In their original form, you can still see them on old square riggers, where they are used to tension and connect the shrouds to the chain plates. We've come a long way since then, with ball bearing and carbon casing. Even though, you might argue, the ends of the arc are coming together again, if you can agree that both wood and modern carbon composites are examples of a fibrous, carbon-based matrix. :)
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Re: DSII Mid-boom Sheeting

Postby TRWXXA » Sun Apr 11, 2021 2:43 pm

GreenLake wrote:PS: on naming: the reason we call these things "block" is that they started out being just that: blocks of wood, with no sheaves. In their original form, you can still see them on old square riggers, where they are used to tension and connect the shrouds to the chain plates. We've come a long way since then, with ball bearing and carbon casing. Even though, you might argue, the ends of the arc are coming together again, if you can agree that both wood and modern carbon composites are examples of a fibrous, carbon-based matrix. :)

I deliberately called what came on the boom a "pully" for a reason. The $3, pot-metal, hardware store , 75# SWL, POS that came wired to the boom has no place on a boat, and should not be called a "block".
Chris S.
DSII #10220 -- "Uisge Beatha"
TRWXXA
 
Posts: 20
Joined: Wed Jan 27, 2021 1:02 pm
Location: Indianapolis, IN

Re: DSII Mid-boom Sheeting

Postby GreenLake » Sun Apr 11, 2021 7:03 pm

OK - you got your reasons :)

(I know those parts that you are talking about and shudder about the thought of someone sailing with them ...)

I'll see whether anyone else responds sooner, but I'm going to be able to swing by where my boat is and perhaps report some measurements.
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Re: DSII Mid-boom Sheeting

Postby GreenLake » Mon Apr 12, 2021 12:13 am

I measure almost 6' between mast and mainsheet swivel, but only about 64" from the front of the boom to the location of the block. (Ignoring the gooseneck).

Hope you can use this information.

(The location of the block along the boom is somewhat adjustable on my boom. There's a very short bit of track there, and I didn't look carefully, but it may have more than one stop for the pin)
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Re: DSII Mid-boom Sheeting

Postby TRWXXA » Tue Apr 13, 2021 10:33 am

GreenLake wrote:I measure almost 6' between mast and mainsheet swivel, but only about 64" from the front of the boom to the location of the block. (Ignoring the gooseneck).

Hope you can use this information.

Thanks, GL! It does confirm what I got eyeballing it -- something between 70" and 73" from the back of the mast.

Thanks, again!
Chris S.
DSII #10220 -- "Uisge Beatha"
TRWXXA
 
Posts: 20
Joined: Wed Jan 27, 2021 1:02 pm
Location: Indianapolis, IN

Re: DSII Mid-boom Sheeting

Postby GreenLake » Wed Apr 14, 2021 10:37 pm

I have 64" + space for the gooseneck when measured along the boom. That's shorter than 73".

The longer distance I measured to the mainsheet swivel in the cockpit.

Looks like the sheet is angled so forward a bit as to very slightly pull back.
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Re: DSII Mid-boom Sheeting

Postby Vanalien » Fri Apr 16, 2021 8:51 pm

I got my DS II out of storage for the season yesterday, and today I measured 70.5” from the mast to the forward edge of the bail. My boat is a 25th Anniversary model, built in 1985, in case that makes any difference. I have only owned it since 2017, but I believe everything is original.

I hope this helps.
Steve
"Nellie Ruth" - 1985 DS2 Anniversary Edition #12819
Little Canada, MN
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Re: DSII Mid-boom Sheeting

Postby TRWXXA » Sat Apr 17, 2021 9:58 am

Thanks!

I went with 71.5 from the leading edge of the extrusion. That'll be about 73" from the back of the mast. That should give a little forwad pull on the boom when it's centered, and a touch more leverage. With only 3:1 sheeting, I'll take all of that I can get.
Chris S.
DSII #10220 -- "Uisge Beatha"
TRWXXA
 
Posts: 20
Joined: Wed Jan 27, 2021 1:02 pm
Location: Indianapolis, IN


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