Sacrilege

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J--
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Re: Sacrilege

Post by J-- » Wed May 07, 2014 4:16 pm

One of the AC72's? The $10 million carbon fiber hydrofoiling boats that killed someone?

If I had $10mil, I don't think I'd spend it all on one boat. Maybe spend $500,000 on something and never got back to work.

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Re: Sacrilege

Post by BOAT » Wed May 07, 2014 4:40 pm

Well, yeah, not that boat, I said one LIKE that boat. I don't have a crew either. :)

I mean it would be great to have a really fast sailboat - and that is where the cat's do their best work

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Re: Sacrilege

Post by mastreb » Thu May 08, 2014 11:05 am

RobertB wrote:
mastreb wrote:Yeah, any two matching macs, two 26' x 4" aluminum pipe, and pipe clamps on the gunnels and foredeck and you've got a cat. Pull up rudders on the windward half and helm from leeward. Better yet you can still get home sailing half of it :-)
That's basically all the MacGregor 36' was, except longer and narrower.
OK Matt - I challenge you to put this together :) How long do you need? The board is here for all the moral support and suggestions you may want (and not want). I understand there may be a source of spare parts down in some North Carolina home salvage operation :wink:
I will henceforth refer to my boat as "Luna Sea Port" and your boat as "Luna Sea Starboard".

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Re: Sacrilege

Post by Divecoz » Sat Aug 23, 2014 6:23 pm

Well BOAT.. maybe Big Cats do with Professional crews..( go Fast that is.) From the ones I see down here its more for a pleasureable platform..but they can act very nasty in waves. You Have to attack ( tack) each and every wave of any size straight on , so as not to have one hull dig in before the other and spin the cat on her axis. There are no less than a Hundred and probabley more, Cats down here and I only see 2 out and about , with any regularity. Then there is the additional cost of a home on REALLY Prime water so you can get them back home..BTW there are quite a number of X's and M's down here.
BOAT wrote:Well, yeah, not that boat, I said one LIKE that boat. I don't have a crew either. :)
I mean it would be great to have a really fast sailboat - and that is where the cat's do their best work

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RobertB
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Re: Sacrilege

Post by RobertB » Sun Aug 24, 2014 6:33 am

mastreb wrote:
RobertB wrote:
mastreb wrote:Yeah, any two matching macs, two 26' x 4" aluminum pipe, and pipe clamps on the gunnels and foredeck and you've got a cat. Pull up rudders on the windward half and helm from leeward. Better yet you can still get home sailing half of it :-)
That's basically all the MacGregor 36' was, except longer and narrower.
OK Matt - I challenge you to put this together :) How long do you need? The board is here for all the moral support and suggestions you may want (and not want). I understand there may be a source of spare parts down in some North Carolina home salvage operation :wink:
I will henceforth refer to my boat as "Luna Sea Port" and your boat as "Luna Sea Starboard".
With that setup, it will always want to turn a counterclockwise direction since mine is BLUE 8)

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Re: Sacrilege

Post by mastreb » Sun Aug 24, 2014 4:21 pm

RobertB wrote:With that setup, it will always want to turn a counterclockwise direction since mine is BLUE 8)
Good point. We'll have to paint mine blue to match.

Lagoons are all built with about a 58% beam to LWL ratio, so on a Mac that would be a total beam of 180 inches, or 2" narrower per boat than they actually are. I think there's acceptable margin to just say that the two macs would need to be simply bolted to one another in order to make an acceptable catamaran, with aluminum tubing support directly across the transom and at the bow. You'd want just a slight distance between them to prevent them touching, and then a tramp woven between them for transit from bow to stern. The close distance between the two boats makes most of the engineering problems actually quite simple: It could literally be built with just a few pillow blocks located on the transom and bow and some standard aluminum pipe. Steerage could be linked at the aft end of the outboards. There would be a lot of running about during a tack, but as long as you set the windward sheets first everything should be fine.

The boats could be sailed sans ballast, increasing sailing speed by a similar proportion to the increase in motoring w/out ballast. Also, speed would be gained by the prevention of heel (force incumbent upon the sails which does not go to heel must go to forward motion).

The two separate rigs would have better and worse points of sail when run together due to wind interference on the leeward rig by the windward rig, with a Beam Reach being the worst point of sail, and everything else being progressively better as you get away from abeam. Running would be pretty awesome even without a spinnaker. It would almost certainly point better, since the Mac's disadvantages in tenderness and light fin keel / light ballast are completely obviated by the catamaran form factor. This boat would not ever get one "ama" out of the water because it lacks the sail area to do that, so it would sail like a Lagoon and not like a Hobie.

It's difficult to determine whether the advantages of the catamaran form would compensate for the disadvantages, but in sum I think the linked rig would likely perform at least as well as a single Mac and probably slightly better, especially in lighter air.

Furthermore, the linked boats could still theoretically be powered WOT by both engines on a plane with linked steering and the ability to control both throttles simultaneously, although the connecting braces would have to be strengthened to counter roll torque and its unclear to me what effect the inner boat's wake would have on the outer boat. I seriously doubt there would be enough force to flip the assembly in any circumstance, although full power on one engine with full reverse on the other would be seriously problematic. Best to avoid planing I think as power imbalances would be hugely problematic. I'm sure there's a reason why there aren't very many planing catamarans.

It's not an entirely terrible idea, and in states where multiple trailer towing is legal and variable-wind lake sailing is the norm, it might not even be a bad idea.

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Re: Sacrilege

Post by vizwhiz » Sun Aug 24, 2014 7:51 pm

I think I've seen this somewhere before...

http://en.m.wikipedia.org/wiki/North_Am ... in_Mustang

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Re: Sacrilege

Post by vizwhiz » Sun Aug 24, 2014 8:10 pm

But on topic... :wink:
I looked into the Mac Cats a few years back when researching the type of Mac i wanted to get. Not an expert by any means, but here's my .02... Please note that this is all from memory, so please don't bust me if I got something wrong.
They were fast and handled well...like 20kts+ and could fly a hull. Small outboard motor(s). Very light for their size (no bridgedeck to speak of, no large internal motor, etc.) Early versions had one daggerboard, later had two IIRC.
Open deck with only tramps. Bimini of sorts could be added to the back half.
52' tall mast or thereabouts. Carried a lot of sail for such a light boat, but made more for the speed/racing scene and less for cruising and chartering.
Very narrow hulls by today's standards (~38" i believe), and much narrower than our 25's and 26's. Not much room for anything but sleeping, so a fair weather weekender for the most part. Had a small galley in one hull, and a small head (porta potty) like the ones in our boats, so no better accommodations than we have. Hulls were not standing room, had pop-tops (hinged, not full pop-up) so you could only stand right in the center portion.
Found several used for day chartering and "catamaran rides", a couple private owner that had been neglected. Still in fair demand as they have a reputation for speed and handling - not unlike our beloved Macs which hold a good bit of value.
Would be an interesting project boat, and could be a fun "big boat" for a young couple that was really more interested in sailing capabilities and who could live without all the accommodations in the cata-condos out there today.

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mastreb
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Re: Sacrilege

Post by mastreb » Sun Aug 24, 2014 8:57 pm

vizwhiz wrote:I think I've seen this somewhere before...

http://en.m.wikipedia.org/wiki/North_Am ... in_Mustang
Yep, same concept.

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Re: Sacrilege

Post by seahouse » Sun Aug 24, 2014 9:24 pm

Catamarans suffer a loss of efficiency because interference between the bow waves causes an increase in drag. This is normally offset by the gains made by making the hulls long and slender.

If you bolt two Mac hulls together not only do you end up with increased drag from this interference, but you benefit from no offsetting gain of having used thinner-shaped hulls.

Cats will also have an advantage in drag reduction when one hull lifts, which is unlikely to ever happen with two bolted together Mac hulls.

The (sidewise) maximum forces on a Mac's rigging (or any monohull for that matter) are dictated and limited by the heeling moment of the boat. Joining two hulls together negates these limits, so the entire rigging and attachment points would need considerable reinforcing and upgrading to avoid certain failure in winds that the monohull would easily handle.

- B. :wink:

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Re: Sacrilege

Post by Catigale » Mon Aug 25, 2014 2:37 am

He's asking 120 which means he will sell for 60.
,,,and his estate will get 30 when he croaks...

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Re: Sacrilege

Post by BOAT » Mon Aug 25, 2014 6:45 am

seahouse wrote:Catamarans suffer a loss of efficiency because interference between the bow waves causes an increase in drag. This is normally offset by the gains made by making the hulls long and slender.

If you bolt two Mac hulls together not only do you end up with increased drag from this interference, but you benefit from no offsetting gain of having used thinner-shaped hulls.

Cats will also have an advantage in drag reduction when one hull lifts, which is unlikely to ever happen with two bolted together Mac hulls.

The (sidewise) maximum forces on a Mac's rigging (or any monohull for that matter) are dictated and limited by the heeling moment of the boat. Joining two hulls together negates these limits, so the entire rigging and attachment points would need considerable reinforcing and upgrading to avoid certain failure in winds that the monohull would easily handle.

- B. :wink:

Yeah, what he said - and where does the mast go??

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Re: Sacrilege

Post by Chopper Pilot » Mon Aug 25, 2014 7:28 am

I can keep going if y'all would want to see what I think it should look like

Image

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Re: Sacrilege

Post by Chopper Pilot » Mon Aug 25, 2014 7:40 am

Image

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Re: Sacrilege

Post by BOAT » Mon Aug 25, 2014 7:44 am

It would never work. It looks like it can't get out of it's own way.

The big mast in the center is supported by what? That idea is a non starter - it would not work, and it would be much slower than one MAC.

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