A possible 65M class multihull?

Ah, the fun of writing rules for a new class. I’m in favor of fewer rules, don’t know what to do about the multimast thing. Maybe just limit it to one rig, or a total mast height of 110cm? I hope that some others jump in on this discussion.
Dick, I like everything that you have posted, with the exception of the unlimited beam. But, lets get some input from several people to try and keep this generalized as to what everyone wants. Once we get some more input, well condense on two or three rule sets, put up another poll, and get the ball rolling.

Sounds good to me - let’s see what the British and Europeans have to suggest.

Allright. You speak french? The French are very much into multi’s, maybe they’ll have some good input. I believe there are some very good french multihull sites, but I don’t speak anything but 1 2 3.

Hi Dick and others,
This program will tile the PDF onto any size paper, I just downloaded it to print the ghost train file, the Adobe Acrobat reader software has the function disabled.

http://www.docu-track.com/home/prod_user/PDF-XChange_Tools/pdfx_viewer

Regards
Nick

Just a thought, re reading the rules you posted Dick it appears a monohull would also fit into the rules? How do you define a multihull?

Might be an idea to keep this point open so either would be OK within the rules?

Brownie - I went back and forth on that one. Having seen a couple attempts at a skiff with “balance pods” - not sure what else to call them a couple of years back, I’m not sure if it (the skiff) would be a mulltihull or not. I got off into thought about the size of float hulls with a percentage of the main hull, but that threw out twin hulled catamarans - and might have disqualified a proa design.

USA #5 (at the time) - an F-48/Mini40 sized trimaran was reported to be scaring the bejeesus out of 10 Raters in Hawaii until it was sold to Australia. I can’t confirm or deny - just note the owner had lots of fun, most bigger monohull owners didn’t want to sail it and I believe Mark Baldacchino (first owner) reported “harrassing” Marbleheads in Arizona when he first started sailing. Here in the US - Clyde Jones has a big one too, but not sure if he has sailed it against anything big. Nothing in mmediate area for my big one to sail against, but I’ve sailed my 1 Meter with the small 36/600 rig and have had no problems with local ODOM class boats unless I really “blow” a tack or run out of wind. I find myself so “into” sailing the boat I forget tactics - like staying in the strong air ! Ha Ha. I mention these as I don’t believe most monohulls will be competitive - but you probably are riight … maybe something to the effect… “Two or more hulls in any configuration” would help to further define an acceptable platform.

Other suggestions?

I don’t think we need to worry about defining the amount of hulls. For one, no monohull with a 1lb leg slug on the bottom could even dream of competing with a multi, unless it’s blowing so hard that the multi’s just couldn’t stay upright, and then the mono would probably have some significant problems.
Dick, I did a little youtube research last night, and the multihulls that I saw all looked to be quite a handfull. I’m thinking now that at the size of boat we are messing with, a larger overall beam might be a good thing. I am still opposed to an unlimeted beam, but was thinking of something along the lines of 85cm?
Also, I have to add, I am experienced with sailing, and rc sailing. I’ve also learned the basics of naval architecture from a young age. I designed my first sailboat on paper at the age of 12. Kinda loosely based on a ec12, but 48 inches, and the sail was much higher aspect, and located much further aft.
Anyway, I’ve never built a multihulled rc boat, but built lots of tri’s that were freesailing as a kid. So, take my thoughts with that in regard. i am however, very interested in getting this class of the ground, and doing it in such a way as to promote it to anyone who has an interest in rc sailboats.

Thanks for your reply. I’m not completely “stuck” on unlimited beam, other than it is just another limiting rule - but acknowledge a tape measure would quickly process any protest of beam width. Based on a few of the small ones I’ve seen in photos and that Haegar has provided, they appear to be easy to build, and then modify and then build a new one. Certainly will take time, but the build of a new idea at this size may move people to try different ideas. If it follows the RG-65 monohull class from what I have seen - the hard-chine, balsa sheet boats seem to remain compeitive with round bilge designs and carbon fiber hulls. Thus a new builder will probably go to a hard chine, while a more experienced builder will go to a more complicated design. Both will be happy, and both will (probably) not be bale to stop at only one boat.

Just to throw out a possibility that once a few of these get on the water, their design and dimensions may soon evolve to a size that proves to work. At first blush, a super-wide beam may be helpful up wing, but tacking and downwind may provide issues. Too narrow of a beam will allow easier tacking, but probably be very tender, and tip sideways easier.

Should we just let it go and see what appears on the water? Should we have Category I and Category II boats where one is unlimited and the other may be beam restricted, minimum weight, etc. ? Not sure - but like the battery issue that tore apart the FOOTY class for a while, making a decision on a specific beam dimension without even seeing performance is a gamble. Because it is developmental, I just want to be sure we don’t close the door on ideas. What about a maximum of twice hull length - or around 130 cm.? That would surely give any foiler ideas an opportunity to develop, and yet it would eliminate the wide open door that a “no minium” would provide.

For my first effort, I plan to stay pretty “traditional” and see what performance and handling problems I find. I still have doubts about a boat that is too light weight, and it’s ability to carry through lulls, or tack in very light and very heavy winds.

I wasn’t thinking about putting lead on a keel, there are other theoretical ways of ballasting a model monohull. :wink: How they would work in practise, I’ve no idea.

This IMHO is what would make the class unique and is a failing with other classes I have looked at, it would be great though to hear opinion from those more experienced in this field.

Regarding tacking problems, this was a similar POV put forward when dinghies that planned upwind developed and everyone said they would stick to the laylines upwind and put in just one tack. Hasn’t turned out that way.

I would be against anything to define number or ratio or anything about the hulls. Just make a box it has to fit in and call it good. One, two, three, or more, what ever shape…

As for mast, I would support a limit on how tall it can be. Do what you want (number of, configuration of, etc) as long as it is not too tall. Something like 110cm should be enough to power up the boat.

I am all for unlimited size and type of sails, including kites.

David

My two pennith worth. :devil3:
Why restrict yourself with all these silly rules.
We have seen what a pig`s ear it makes of other classes that have tried it.

The only criteria that needs guidance is, “overall length must not exceed 65cm.”

Everything else will sort it`s self out.

Excellent :smiley:

That does seem to be the simplest way to go. But one complication, does this just include the hull, or does the rigging have to fall into the 65 cm overall length? Are bowsprits or bumpkins included? I’m not trying to play devils advocate, just making things clear. For my viewpoint, the 65cm rule should be absolute. Nothing can project past 65 cm, including rigging. Not very hard to do in practice, so I don’t see anything wrong with it.
Adding a new poll.

To be trully multihull, I’d rather go for a surface (22.5 dm2 to re-use the RG65 rig ?) and leave all freedom to the hull !!!

Small multis are suffering from insufficient longitudinal stability, it would be a pity to set a not-so-good sailing rule.

We should target at trying to obtain the fastest possible model fitting in the trunk of a convertible car. The RG65 rig (110cm mast / 22.5 dm2) is a good start.

The reason I’m not convinced that 65cm overall gives a sound model is experience of the “jauginette” (Google it), a rule with all allowed with a 50cm hull(s)… It ended up with monohulls as multis had a two-digit chance to capsize on jibes, espacially when fighting in a regatta.
We ended up with massive foil rudders when the wind was up, even for the monohulls


BR
Calou

Hi Dave -

we went around a bit in the F-48 class rules on this subject. Conclusion - the racing rules we would use do not/did not contemplate a sail that might be several meters away from the platform or hull. As example, a boat “Finishes” when any part of the boat crosses the finish line. Kites could (in theory and probably practice) be flow a meter in front on a downwind leg, thus “finishing” well before any other part of the hull. On a reach or beat, if flown to windward it would potentially eliminate a boat from passing a leading boat to leeward due to kit and control lines. Not saying a kite would show, but if it did. it would send rules into a spiral.

[SIZE=2]I tend to agree with Ian, as the issues so many think need a rule, will probably eliminate themselves due to practicality on the water. I do see the issue noted by “Calou” in that a 65 cm boat could end up being a 55cm boat allowing a rudder trailing behind, of 10 cm. The rules suggestion for two or more hulls would at least address the monohull versus multihull issue. As for rudder abberitions, the rule IanHB cites could include max/minimum for hull which would include any bumpers, transom rudders, sprits, etc. As for mast height, many current multihulls often have masts twice the length (or more) of the hulls, thus I suggested 130 cm. maximum of all rig heights added together (for multiple rig boats). The 2 Meter multihull class sucessfully uses a mast height limit and allows whatever amount of sial material to be hung on it. Seems to be working well.

IAN - thinking of playing?

[/COLOR][/SIZE]

Hi,
I have just posted the linesplan of the DEPRONI here: http://www.rg65.de/forums/showthread.php?tid=778&pid=11073#pid11073

Thanks to Peter!

However, please be careful, it is just a quick and dirty sketch in Freeship 2.6. It might still contain some minor errors.

Hey Dick, always thinking of playing, but “so much to do and so little time” as someone famous once said.
I tend to spend so much time on this bl**dy computer, playing on “Virtual Skipper” (now ranked about 1200th in the world) and around the various forums.
I do get to sail every Sunday and sometimes during the week and I have just started playing golf to get me some exercise. Enough about me and back to the matter in hand.

I truly feel that all the concerns anyone has about sails, rudders, channels, kite power, bowsprits, spinnakers, beam, mast height, foils and everything else will work it`s self out as people try to push the boundaries and find that so much of this extreme stuff that we dream up does not work in the real world.

If you allow the maximum overall hull length to be 65cm, with no restriction on anything else, then as I said earlier, the class will truly develop.
If that means a monohull style of central hull with outrigger stability pods then so be it.
Let it be its self and I predict you will see a fairly conventional trimaran style of craft with two channel control and a conservative swing rig just as we have seen previously.:graduate:

If someone has the balls to construct and successfully race around a standard course with a kite powered proa, using adjustable hydrofoils, with six channels of lithium powered micro digital robot controlled inputs while vewing on a tera linked screen via miniture cameras then more power to his elbow. :devil3:
Here endth the rave. :lol:

Hi Ian -

I would say “I’ve got the balls —but certainly I had NO idea !”

:smiley: :stuck_out_tongue: :smiley: :lol:

thanks for your comments and as always - your wisdom.

Dick,

I also think simplicity - overall length only (includes any fitting, bowsprit, rudder, foils, etc).

Limit mast height if you have to (to same as rg65) i dont think it is needed (and most would soon find out why)

Limit beam if you have to (to same as length?), but no box rule where you could make a longer diagonal main hull with smaller (foiling) floats.

Like Ian - if someone could make a 6 foot tall rig work, on a 6 foot beam, I would certianly like to see it (to copy of course!)

Jon

I don’t understand how we could make a regatta start with 130cm wide models…
Also, it would be a pity to reduce sail because of the downwind leg only. Before rules are set, I’d recommend that we test a few models to check their practricability. Making the hull(s) a few inches longer would make such a better performance and would simplify the design also.

The simpler thing to build, a 80cm x 60cm cat’ weighting 500g… as long as it can still be easily transported, why not enjoy ?