Rig heights

Technical discussion of ARC products
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JupCat
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Posts: 13
Joined: November 12th, 2021, 3:09 pm
Boat Make/Model: SC17

Rig heights

Post by JupCat »

I just bought what I think is a SC20 tall rig, the guy I bought it from said it's from a Tornado, but I didn't think the Tornado rig was this tall. It is 38'6" and has a single spreader and the same extrusion profile as a SC. Came with a sail also that looks like its from a Tornado.

I am about to embark on a silly journey to stretch and widen a SC17 and add a taller rig. My thought is to create a bigger fast boardless boat, shooting for 18'6" long and 9'6" beams. I've completed my cranial calculations and have most of a plan. I think I want to take this newly acquired 38'6" rig and cut it down to 33' like a SC19 and ARC21.

So I guess my first question is, the correct rig height/length for the SC19 and ARC21 is 33'??
Matt Haberman
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Re: Rig heights

Post by Matt Haberman »

Hi JupCat,

It was not a Tornado rig, the 38'6" Rig is from either the SC-20 Tall-Rig or the ARC-22.
You stated it was a single spreader, I am assuming there are outer and inner diamond wires on those spreaders? Assuming this is the case, then it was an ARC-22 mast. However there were also a handful of SC-20's that upgraded to the ARC-22 mast rig so it could have come from there as well.

The Standard Rig on the SC-20, SC-19X, SC-19XL and the ARC-21 were all 33' masts. The rigging on the SC-20 was a bit different than on the SC-19X, XL and ARC-21, but they were the same extrusion and length.

With regards to stretching the SC-17 and making it wider. I am going to suggest you save your time and money as I believe you will be disappointed with the result. The SC-17 does not have enough hull volume to support the righting moment you are going to have after making it longer, wider and taller. If want a bigger boardless boat what you should be looking for is an SC-19X which is boardless, has a 8'6" beam and a 33' mast. With the 8'6" beam the hull volume on the SC-19 is adequate, but with a 9'6" beam it would be questionable in anything but the lightest of wind conditions. If you cannot find an SC-19X, look for a SC-19XL and just cover the daggerboard trunk openings, they are essentially the same boat.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
JupCat
Novice
Posts: 13
Joined: November 12th, 2021, 3:09 pm
Boat Make/Model: SC17

Re: Rig heights

Post by JupCat »

Thanks Matt. I'll post some pics of the rig after I pick it up tomorrow.

I think 33' is the right height and will give me plenty of options on sails.

I knew the 'save your time and money' comment was coming fast. And you and others might be right. But, I've got an excess of SC17 hulls and believe I can make it a solid boat. I'm not trying to build an F18 and I think the 17 hull shape is better as a boardless boat than the 19. Also, there aren't many SC19s of any kinds available around.

My intent is to build a boardless boat with more tramp space that can still move when needed. To optimize the hull volume advantage I am going to cut the hulls just aft of the sidestay, lengthen 10", reattach with six glass laminated foam core stringers and rebuild the section with the same glass foam core sandwich. At that point there is the most under the waterline hull volume and still fine hull shape. I'm then going to add approximately 8" to the bows, but I haven't got that shape totally sorted yet.
JupCat
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Posts: 13
Joined: November 12th, 2021, 3:09 pm
Boat Make/Model: SC17

Re: Rig heights

Post by JupCat »

So the mast I bought isn’t a supercat mast and might be a tornado rig. It’s 32’8” and tapered at the top with a rotating hinge to step. It will still work as a test rig for now.
Matt Haberman
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Re: Rig heights

Post by Matt Haberman »

JupCat,
Tornado mast is only like 29' or 30' long at the most so I don't think that is from a Tornado either.
I saw your pictures on Beachcats and I do not recognize that mast step/base. Definitely not from a SC, Tornado, Nacra, Prindle, or Hobie.. don't think it is from G-Cat either...
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
JupCat
Novice
Posts: 13
Joined: November 12th, 2021, 3:09 pm
Boat Make/Model: SC17

Re: Rig heights

Post by JupCat »

Merry Christmas Matt.

Yeah, I saw the same, closet thing I’ve found is like a tornado, but they are 29’ish. It’s odd. I’m going to fit the SC mast base to it and fab the standing rigging and see what happens. It’ll work until I find or splice a proper mast. A SC20 popped up close to me with some hull damage from hurricane Ian, but everything else looks ok from the few pics posted so I may go take a look at it.

More questions. What is the foot length on a SC19XL square top and a ARC21 square top? What mast was on the SC18 Square?

Thanks, Mike
Matt Haberman
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Joined: November 10th, 2003, 8:22 pm
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Re: Rig heights

Post by Matt Haberman »

Mike,
The SC-18 used the same mast rig was the SC19XL. Don't recall the for measurements of the top of my head, I'll have to check.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
JupCat
Novice
Posts: 13
Joined: November 12th, 2021, 3:09 pm
Boat Make/Model: SC17

Re: Rig heights

Post by JupCat »

I think I've been talked out of the project in the current form. I'll keep searching for some 19 or 20 hulls.

I picked up a Vanguard 15 to hot rod for the kids, so that will scratch the itch while looking.
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