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Aug 25, 2016, 06:13 PM
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Crunchy Frog's Avatar
Quote:
Originally Posted by Dick L.
Found a set of templates for a 2 Meter catamaran that are free and can be found on the Multihulls thread on RCSailing.net in case anyone is serious about trying a build.
Can you post a link?
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Aug 25, 2016, 08:23 PM
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Dick L.'s Avatar
CORRECTION: These are for a 2 Meter trimaran...NOT a catamaran !


http://www.rcsailing.net/forum1/show...trimaran-build

Post #6 are float templates
Post #13 are main hull templates
Page #19 - templates cut out - both floats and main hull
May 09, 2017, 04:28 PM
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Dick L.'s Avatar
Just to update the build - which WILL be very SLOW, since I have a grandson's electric train model layout to fabricate and complete, and as I was getting ready to cut templates, my band saw died. Since it was in the fall, and not enjoying winter cold work, I finally got band saw issue taken care of, and also managed to cut foam hull templates.

Laid out in the photo are the templates for creating one hull (of two). With the total hull length limited to two meters (about 76.74 inches) the layout of templates is only 72 1/2 inches - but I haven't yet cut the spine for a reverse thin bow. My templates in photo are currently sitting at a spacing of 6.25 inches, so I can cut the bow to the plan size and them simply adjust the remaining templates to a slightly shorter length overall to come in under the 2 meter minimum.

I assume by now there must be seven or eight hulls/boats under construction - both cat and tri configuration (based on number of emails with questions about the build, design and number of hulls in questions). Frankly it would be cool to see maybe two or three show up here in the US.

Next step is to cut the outline of the bow and then get a building board built. Until I get the hull templates pinned down, I am still contemplating construction- wood strip - or foam with foam left in place. Because of a rather "funky" looking bow and foredeck, I may build each hull in two parts. Hull and then deck. This will help since removing my hull from templates in one piece isn't possible, so that means building two separate hull plugs. If I build deck in 2 parts (hull and deck) I can pull the hulls and will only need one master plug.
May 10, 2017, 01:12 PM
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DLord's Avatar

2 meter cross arms/ diassembly


Dick, my Fire Arrow tri is only 65" LOA(1.65m) but is 79" wide(2m). The tubes I use are 1.125"(OD) with a .0625" wall from Rock West. I use the ferrule made by them for this tube which allows the ama to be simply unplugged for transport. The ferrules fit snugly but not too snug-glue one side... Might work for your boat.
May 10, 2017, 01:26 PM
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Dick L.'s Avatar
Thanks Doug. Will give this solution consideration. Is there any mechanical solution to keep the tubes from slipping out of the ferrule? Maybe set screws, cable ( wire) with turnbuckles, etc.? How does the platform resist twisting if tubes are inserted into location by slide on ferrules?

Thanks for any further level of information.

Dick
May 10, 2017, 01:47 PM
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Dick,
Make one plug! A single plug, mold after the plug is made perfect, cast multiple hulls from mold! Cat, or Tri, or hulls for other builders. A simple mold can produce 10 hulls. A more intricate mold can produce upwards of 20 hulls, more than I think you will ever need to provide. I may be wrong.

I am working on designing and building a 65M. Right now it is a Cat with a rig on each hull, central swing arm winch to control both sails together. Debating connecting the two rigs or letting them run free of each other. Right now a 2 meter is to big for my small shop but the idea of two smaller rigs on a Cat is proven in sit-on-boats, and foilers. They would reduce the height of the Center-of-Effort of the sails improving righting moment and doing something about pitch poling.
Still could have the same or more sail area, just spread between the hulls. With rigs on both hulls you would not need heavy crossbeams to support a single rig between the hulls. The rigs could be mounted on/in the hulls as in monohulls. The only downside I can see is it would look odd, and take some time to get used to.
May 10, 2017, 05:08 PM
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Dick L.'s Avatar
Niel,
The problem with using a plug and then making a mold for hull layups is there are numerous areas where the hull and/or deck have negative (reverse) angles which would prevent removal from a mold.

After looking at the general hull shape of the hull templates, I am leaning to a possible strip layup, buy using 1/2 thick foam strips (to eliminate sag between templates) and then possibly wide but 1/4 thick foam for fairly flat areas. Not sure but will have to try out to see if it works.

Will see how a hull shape develops.
Dick
May 10, 2017, 05:26 PM
Registered User
Well, I have made molds for M boats that were two half molds to make a roundish hull. These were right and left molds with the seam along the deck and rocker. With an open stern I was able to seal the two hulls taken from the molds with a glass epoxied tape along the seams. It was one of the most waterproof hulls I ever made. The molds produced 25 hulls before the boat design was no longer competitive. I lost time and money making those hulls so I don't produce multiple hulls any more. But the system works, just make sure that your hatch openings are included in the molds. It is much easier to think ahead than to cut through the hull when the tape is in place.
May 10, 2017, 06:59 PM
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Dick L.'s Avatar
I used the vertical seam for my Multi1 trimaran. Worked good for amas, but was a bi#*h to align centerline stuff in the main hull,without a point of reference. ( hatch, keel, rudder, mast, etc.) A horizontal cut is much easier for locating beam width, centerline, etc. (for me at least) LOL
Last edited by Dick L.; May 10, 2017 at 09:20 PM.
May 11, 2017, 08:56 AM
Registered User
Dick, just tried to help.

I would think that the centerline would be obvious as the seam on a right/left hull would be its location.

On the plug you could locate where you wanted all the places needed to be. Cast the first half mold with a temporary wall (I use placticene) along the centerline of the plug. Make sure that wall has several keyholes in it. That wall goes all the way around the plug, top and bottom. Cast the first half. Once the first half is cured, remove the wall, carefully turn the plug and the half mold revealing the unmolded side, and cast the mold on the new side. When that has cured, split the the molds and you can cast hull halfs left and right. These boat half hulls can be trimmed, sanded, taped together, and sealed with the aforementioned glass, epoxied tape. Then cast as many half hulls as you want, in the pair of molds!
May 11, 2017, 09:37 AM
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DLord's Avatar
Quote:
Originally Posted by Dick L.
Thanks Doug. Will give this solution consideration. Is there any mechanical solution to keep the tubes from slipping out of the ferrule? Maybe set screws, cable ( wire) with turnbuckles, etc.? How does the platform resist twisting if tubes are inserted into location by slide on ferrules?

Thanks for any further level of information.

Dick
-----------------------------------
With two tubes and snug ferrules there is virtually no twist to the platform. I have a no-stretch line rigged with a simple bowsie between the two amas across the boat so there's no chance of an ama slipping off.
May 15, 2017, 06:52 AM
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glouis's Avatar
Quote:
Originally Posted by Dick L.
Just to update the build - which WILL be very SLOW, since I have a grandson's electric train model layout to fabricate and complete, and as I was getting ready to cut templates, my band saw died. Since it was in the fall, and not enjoying winter cold work, I finally got band saw issue taken care of, and also managed to cut foam hull templates.

.
lol I know this too well... have not made any progress on my 2m multis - 2 RA class boats have somehow squeezed in. One was not sailable but the hull was sound so after gutting it I updated a lot of the fittings and built a new rig, new electrics, now needs sails and should be back on the water. The other though raced had some structural issues with the deck liftig at the join with the hull under load so it was a complete gutting and sanding to the primer for the hull and deck with epoxy/fg reinforcement on the full length of the join and now it is rock solid. I faired this in and now looking at improving the deck fitting layout with new electrics... not easy... ;-)


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