This class sounds a good idea. I have the pieces of a mini40 I am about to give away, and due to a move, have to sell my share in a full size tri. I am keen to have a pair of whatever I decided to build, as it is so much more fun racing than just sailing around by yourself. A couple of 65cm tris seems like a fun project.
Am wondering however, if they will be too ‘twitchy’ and be easily overcome by wind gusts?
As for how to start a regatta with 130cm wide boats - not a problem. My full sized tri is 840cm wide, and we manage that!
Well, most people want the only rule to be 65cm total length, so I’m gonna start designing and building based on that. For my first boat, it’s gonna be about an 85cm beam I think, but I’m gonna set it up so I can change the beam pretty easily. Removable arms should accomplish that, and that way I can play with the angles to find the optimum height for the outer hulls. I was thinking of making the outer hulls asymetrical, with an airfoil shape to help compensate for leeway. What’s ya’lls thoughts on that? I know the old hobbie’s did that, seems like a good idea. The construction of this thing is gonna be balsa, basically a hard chine with the chines rounded off, pretty much square. I don’t think I’m gonna mess with foils yet, I just wanna get a test bed in the water, something that i can change the parameters around on fairly easily until I find something I like.
Anyone else up to starting a build?
This makes a “LOT” of sense (oh oh :scared:) and will probably be what helps the rules evolve to something we agree on “After” the performance is observed.
I have 2 RG-65 monohull’s left to finish of my fleet of 5 and then will see if I can also come up with somthing for the water. In most likely case, it will probably be modeled after my 1 Meter trimaran hull and float shapes.
There are a few flat bottom boats in the works, plus a really light weight triple-pod (for lack of better description) - and we could always adopt the FOOTY course idea to translate performances into time. A dozen or so of those times for same distance should start to identify ideas that work - or don’t.
Yep, just waiting for the balsa sheet I’ve ordered to turn up then I’ll start a thread and base it around the 65CM length rule.
I’m planning for hull structures out of thin balsa sheet bent into shape, movable ballast similar to the Aquataur model dinghies and rig that cants to windward.
Ummm - What will fit in my “trunk” may be too big for yours. I have a pickup truck so could carry multihulls up to 2 Meters without issue. Then if still too big for truck, I can pull out the 27 foot (8.22 meter) horsetrailer and carry it inside.
I kind of think most have focused on the 65 cm overall length for everything - bow bumper, sprit, rudder, etc. and a mast that will probably not be limited (but most likely will be close to the 110 cm of the current RG-65 monohull) - so they can use the same rig.
This is by no means teh final rule - just from what concensus I have read into the thread.
Somewhere soon, we will ned to ask for specific rules to be written, as yours above is way to open for anyone to build to, in my opinion. I plan on mine being 65 cm overall length, not sure of the beam and will start with a very tall mast, and start cutting it down until it is something that can be managed on the water. Keeping track of how the boat sails and what issues I find, will be helpful when it is time for the real rules to be adopted. I would urge everyone that is going to experiment to do the same so there is objective, rather than subjective discussion.
All right, let the accumulation of balsa dust start! For an internet course, how about we set up something along the lines of the footie thing, but set the two markers about 150’ apart. One anchored, the other with a sail to hold it downwind. Start at the rounding of the leeward mark, end at same point.
Dick you have any suggestion on on how to modify an existing plan and more importantly how, for a complete multi novice. Something like target weight/displacement and size …… How much rocker, for example, need the main hull to have, if a rocker is necessary at all? Something like that.
You suggested the Ghost Train in your first post, are there any other plans/models that would be easy to convert/redraw?
I think a whole new area for discovery, since most multihulls have been large, and these are very small in comparison.
In one of my photos posted somewhere (too hard to keep track) is a photo of a red 1 Meter trimaran sailing. It is a simple down-scale of the UK Champion “PULSE”. I ran drawings and he built it. Seems to sail decently and looks to be on its lines based on photos I got.
There is GHOST TRAIN, SNAPDRAGON, PULSE, WATER RESIST and of course the various designs Ernst/Idealist is pushing - and while all are of Mini40/F-48 size I would think you can downscale the main hull and just keep some volume in the floats. There is also my MultiONE template lines out here which could also be reduced.
I would guess that the target weight will be somewhere in the area of right around 1 lb. or so. The RG monohulls are coming in with a bulb weight of 1 lb. so isit possible a full boat could weigh that much? Search some of the posts as the guys from Germany have provided the weight of the DEPRONI which is nothing more than foam board, and taped together. Rocker will be an experimental thing, but I would opt for rocker to allow for easier tacking and finding a happy middle ground so you don’t get a lot of hobby-horsing.
Size - no more than 25 1/2 inches (65 cm) long and I don’t know that I would go with the same size for beam. On one hand, beam can prevent tipping, but makes tacking more difficult. Would also start out with a mast meeting RG-65 monohull size 110 cm/about 43 inches but that might be your light air “A” rig.
A lot of these will become design standards as some boats get on the water and owners see how well behaved they are.
Im going to build a RG65M now as well (not guaranteeing to finish though), doing the Ghost Train from the plans Dick put up. Floats are going to be made up of end grain balsa laminated together bread and butter style as an experiment like the earlier pic of the foam section. I get the balsa for free;) is the only reason. What weight should I aim for for a float?
Nick
Thank you for the answer Dick. It’s more or less in the direction I was thinking …
Something else I was thinking about, some times ago there was some trimaran info posted from Australia where they were adding omas to existing old M’s. How about something similar for the Tri 65? There are some narrower hulls (Aspara?) that could probably serve the purpose, and a 1lb boat is not totally unrealistic … any thoughts?
Ha Ha - I will start using the comment …"If you got it - give it a ‘tri’ - as in trimaran.
Ok - bad joke ! :rolleyes:
Actually, the converted “M” trimarans worked very well in their local fleet until they went to a different regatta site where multihulls built specifically as a multihull really beat them. his was reported by one of the participants with the modified Marblehead.
Now that being said - until they are on the water - everything should be a winner… [smile] …until it is beaten. If you already have a hull to act as a main hull of a trimaran, I surely would give it an opportunity to prove itself. Remove the lead bulb (or retain it as training wheels) put in a new keel blade without bulb, probably a deeper rudder to keep it in the water when windward float and center hull lift clear of water, and maintain the largest legal RG-65 monohull rig/sail (110 cm mast height, and approx 300 sq. inches of sail area) - some carbon or laminated balsa cross beams, longer side shrouds, and some foam floats. It sure would eliminate a lot of build time, give you an idea of possible speed, and if the concept of a monohull plus floats would work.
I know a few guys in teh UK were experimenting with similar ideas using older 1 Meter boats.
For first few sails, I would tape a piece of foam to top of mast to keep from turning “turtle” if it does go over in a gust. Finally, look at your winch to see if it has pretty fast reaction times. If boat starts to tip while sailing upwind, if you have a slow winch, just steer higher (into the wind) and the boat should settle back down to the water. If you steer away from the wind, it will most definitely go over since you are presenting even more sail area surface to the wind, and you probably have sufficent drag to eliminate the acceleration you would get sailing an ice boat or land sailer.
Ok, I dont thing the balsa end grain will work as actual hulls, as a plug it would be fine but I think I will just strip plank it(and bear the cost:rolleyes:)
Nick
Ive now completed the basic construction of the floats, Because its my second multi hull (first one was years ago and wouldn’t tack) I simplified further and went to a chine design, I will get some photos up in due course. I figured that my Razor Footy sails well enough(in explanation of going for the chine). I’ve attached a very basic outline of the floats with the bow, centre and stern formers that I used. Its the same rocker as the floats of the Ghost Train. I’m going to build the centre hull in a similar fashion.
Regards
Nick
Glen, I figure about $25 in balsa and glue, standard radio gear under $100 even upgrading one of the servos if needed, maybe $50 for the rig including carbon tube. lets say allowing for extras $200 in total, I’m spending considerably less as I already have most of the radio stuff
Here are the promised pics of progress, I am sort of bodging it together and discovered my main hull is actually slightly narrower than the floats:mad: Ill run with it. Straight single carbon tube cross beam I think.
Nick
Hello Nick, excellent. It may be better for future reference to start a new thread as eventually anyone wanting to learn from your experience will have a job ploughing through this thread.
I’ll be starting a new thread in a day or so documenting my 65CM multihull.
Nick I would respectfully suggest that two cross beams would be a better bet.
The forward one should be sufficiently high and back to remain out of the water when the nose goes under (which it will, trust me )
The twist actions of the floats would then be shared amongst the four joins instead of just the two in the middle.
