C'mon Andrew K. I have quite clearly stated that if all three hulls are restricted to fit in a square box, then you should use maximum beam! Of course you can go narrower, but why the hell would you want to?

Have you actually sailed a Multihull yet? It sounds like you have not. If you had, and for someone who quotes he manufactures these boats as well, you should at least have some comprehension of how all these forces work!

I can assure you, I am not wrong!

Multiman

multiman,
thanks for personal attack...perhaps you had seen that i posted photos of my tri on this site...yes i have built them and sail them...
I said that perhaps you were slighty wrong by stating "YOU CAN ONLY AND SHOULD ONLY PUT THEM AT THAT MAXIMUM BEAM"...
clearly this is not the case when dicks boat measures 1100mm and others that i have measured are between that and 1050mm...
the question i was asking is what is the general concensus on beam...

perhaps you could post some photos of your boat....

Hi guys,t'is I tricat !?to those who are mystified as to why there seems to be such an interest
in the max beam of a trimaran.Here are my thoughts on the matter.A trimaran sails better and faster
to a point if it can cut down its hull drag,so lifting the centre hull JUST clear of the water is a good thing as long as it does not force the lee float under or cause the cross beams to go under.This means that it can be balanced by either a taller rig, or less beam.If you look at the trimaran from the bows you can can see the moment arms of the rig and the lee float.By adjusting the height of the sails you lift the centre of effort of the rig,by pushing the beam out you get more stability,it is a balancing act.It is not good to alter both at once,so the rig being cheaper and easier to make
seems the best one to start with.If you are building a racing multihull you need the max power,this is why Multiman says why start with a narrow beamed multi in the first place.As you can see this leaves the rig.It can be too high,and this causes seriuos problems if you sail dead before the wind,especially if you have a fine nosed multi.My personal thoughts run loosely around, if the centre of effort is taken and a line taken from it at 45 deg downwards, I do not like it to cross the water line outside the confines of the hull either forward or sideways,if it does I try to make it as close to the hull as possible.The reason is that the drive force will be giving an extra moment arm to try and turn the boat over.As you can have various rigs for your multi it eases this problem to what suites your particular boat in certain wind conditions.My testbed [foamy]top rig of 970sq ins is only 41ins high and sails like a formulae 1 racing car in most weathers.I will try and put a photo of it on my profile.
Multiman has asked if I could put a video of it on this forum,I'd love to but it does not seem to want to upload at the moment.I'll keep trying[:-] Regards to all Tricat

thanks tricat...out of curiousity i will try the 45' on my current rig and look at where that point is in relation in the morning...
cheers
andrew

Hi guys
Im up to making the cross beam on my Cat, But i'm not sure what to make it out of, so it
will be strong and light.
Ive though ply or fiberglass...But im thinking fiberglass will bend and so will ply, so
im out of ideas.

Thanks

Midget -
here in the States, I found and use 1/2 inch diameter (12.7mm) carbon fiber straight wall tube. You can get a 60 inch (1524mm) long piece for around $18.00 - or you can look at Kite Stores and they may have the same but 48 inches (1219.2 mm) long for around $10 each.

The long one also works fine for a mast - or use two short tubes with a ferrule/joiner in length. My first boat (not a great performer but scaled after my big cat) used aluminum tube. Kind of heavy compared to the CF tubes. If $$$$ too much, look at a fiberglass tube. A bit more weight, but less cost.

Probably a high shipping cost, but here is an idea of sizes and costs. Note they also sell heavy weight rip-stop nylon or polyester fabric by the yard for sails if you decide to make your own. I use the 1.4 oz. stuff. A bit stiffer than the lightweight 3/4 oz. spinnaker cloth.

[link=http://www.kitebuilder.com/catalog/index.php/cPath/33?osCsid=6b5a68fc148978c6f7468a36f5c06e3a]The Kite Shop[/link]

You should have similar shops there in the UK for the kite-builder guys. Lots of cool building stuff at pretty good prices.

Dick

As for my boats, there have been pics on here already, you can also go to one of my websites.
http://www.apolloboatservices.co.uk

I have been producing Cats and Tris since 1994.

Good Day!

Multiman


<mod edit - adjusted for tone>

fair enough....consider that issue dealt with

Andrew K

How very condescending of you!

Multiman Manufacturer of MANY RC Trimarans and Catamarans.
Manufacturer of Full size 26' and 44' Sailing Catamarans
Manufacturer of F1 Powered Catamarans.

Next?

We need a lot of co-operation if we ever expect this "multihull thing" to take off and be viable classes around the world. New sailors will blow off the class/threads if they see this kind of bickering going on over a mis-stated/mis-interpreted statement. Save this stuff for important things. An argument over this is easily answered by reading the rules which say a "maximum" for beam and length dimensions. In actuality, nothing prevents Tricat (as example)from racing his M1M within the Mini40 class - there are no minimum sizes - only maximums. What actual dimensions others are using for thier boats seems to be a logical question.

let's get on with the reason we are here - r/c multihulls, their improvements, building techniques, race results and new ideas. Both of you have too much info and experiences to share


<mod edit - adjusted for tone>

nothing ever changes i see ? multiman is still trying to put people down

Hi Midget,As DickL is talking about f48/Mini 40 size,re cross beams and sizes,I will give you an idea of what I use on my testbed 1M Multi.Both fore and aft beams use 1/2metre 8mm carbon fibre tube with a 1metre 6mm tube running through it[or whatever your beam requires].The 8mm is secured to the centre hull the 6mm tube is just taped up to stop it from sliding through.This allows you to dismount the floats easily for transportation if needed.This arrangement will handle 3.75lbs of hull in any weather without any problems at all.One point about carbon fibre is the ends of the tube do require binding or in time they will crack.I use electricians tape[a couple of turns will do]To give you further info on strength,I can pick the multi up by the outrigger float no trouble nothing gets strained, so they have plenty of stiffness in them when you need to lift it out the water in awkward places. Regards Tricat

Dick L

I utterly agree that ANY Multihull below what are Class Rules in MINI40 can be entered for any race in the MINI40 Class. That was not the question as I understood it.



<Mod edit - edited for content and tone>

My apologies for not specifying the F-48 size versus the 1 meter size.

Although I do use the same diameter carbon cross beams on my 1 Meter multi only because I had a bunch of tubes already purchased. On that one, I too use tape wrapped around carbon tube for locating left/right location on main hull and as "stops" for float attachments. The carbon tubes are held inside the glass tubes on top of the floats by the rigging. Mirror hanger are screwed to outside of the tube (wood dowel inside) to which the "Y" harness for side shroud rigging is connected. Hopefully photo will help explaining this method. It is a glass tube mounted tot op of float into which the carbon tube is inserted. A small wooden dowel is pressed inside the carbon tube and the hanger is screwed to the wood.

Cheers

Multiman - my point was only an example of the rules I suggested would have covered the entire size issue. For both the Mini40 and F-48 Classes, the rules specify maximum dimensions - and it was my point to show a smaller size (or boat) still met the rules.

To clarify "my" reasons for a narrower than allowed beam is the hope that tacking will happen faster and all three bows will cross the eye of the wind faster by being closer together than if they were further apart. My focus direction is for a fast tacking boat and I will give up a wider beam to achieve that. If I find it wasn't helpful, I can always widen the beam out to it's allowed 48 inch maximum (1.2 meter) size. Hopefully that will also address Andrew's post of the difference in maximum beam compared to a less-wide beam?

Regards - and keep the ideas and suggestions coming.

Dick

Whatever mutiman your the know all here ,I do plenty mate i just got tired of your attitude which stinks as i think Andrew allready hinted at.All you do is put people down ,your posts on here prove this .I stopped posting on here becauase i got sick of your attitude,its suposed to be fun and people like you take all the fun away.

multiman,
i had wondered why my post got you on the wrong foot to start with,
my post was never to come across as to whether you have any boats, or boatbuilding experience,
if you took it that way then i apologise, but that was not my intention...
anyway,perhaps "everyone" can move past this issue now and we can start freely discussing
rc tris again...


i looked at your website,the boats look cool, have you got any other images or webpages to look at...
cheers
andrew

Notice to one and all. If you are not prepared to play nice your posts will be edited or removed. Having reviewed this thread I cannot really see the need for such tone or direction so in the interests of restoring a positive direction several posts have gone and others were edited. Anyone want to discuss the topic further please contact me (or the party with whom you have something to clarify) directly.

On a more personal note - I have dealt directly with world class sailing teams over the years (Oracle, Stars and Stripes, Team NZ, a few Volvo teams, Mari Cha, Dame Ellen, Around Alone, Olimpics, etc etc etc) so I have seen plenty of egos. But wouldnt you know the best teams had the smallest ego. They work well with others, complimented and develop the sport, and continue to encourage others to follow a similar path and share the dream.

In email correspondence with both the moderator of this forum thread, as well as the forum administrator, the concensus of opinion/view was that they want to see positive posts that encourage the hobby to be an interesting one and to help membership/participation grow. Dissention and disagreement IS ALLOWED provided it is done in an adult and courteous manner.

I think the "hinted at" message reply from both of them was that if in disagreement, state your "opinion of the issue" (not a personal view of the other poster). Better to not repond, than to begin taking on an edge of personal attack which will easily be grounds for having the post edited or removed.

Since this is such a great site for sharing of ideas and information, I strongly encourage all to heed the suggestions from the guys running the forum and thread. We all can learn MUCH regardless of how experienced we are or think we may be.

Let the ideas and discussion continue ................ please?

Hi guys,In reply to an earlier question Midget asked what to use for the cross beams.DickL answered this question in full.It also brought up the question that if certain materials bend too much
what could he use.Multiman mentioned laminates.This method is like ropes the more strands [too a point]the stronger it is.It allows curved shapes to be made,it gives great strength,the only thing that may go against it is weight.As I personally have not built any laminate fittings of the type required,
I would rather have someone in the know advise how to build this type of cross beam.
In my dingy days one of the solid ash ribs[2" by 1"]continually broke in heavy weather.It was replaced with a laminate rib 4 times 2" by 1/4" ply strips.the ribs in question are still in good condition 56yrs later.O-ooops I will give my age away?????

Regards the other matter.As DickL says Let's keep the info coming in for the benefit of all. Regards to all. Tricat

As an addition to what Justaddwata stated, a few of the members in here have shown their hand as being sellers of sailboats or other RC related goods. For those of you that are dealers please review the site rules concerning those of you that are in the RC business. I know who you are and expect you to conform to the RCU rules or face Moderated Status or banishment from the site for failure to comply to the rules that you agreed to when you signed up here.
Any questions, PM Matt or myself.

Now, back to the program already in progress.

Hey Ron -

thanks for the reminder.

It might be worth the effort to look a bit deeper into signatures and claims. In the SAILING multihull r/c world (this topic/thread) - most who claim to be builders are what I affectionately call "HOBBY BUILDERS" - you know - those guys who do some design and building in basements or garages - and when done, offer the boat to recoup costs for materials and labor to allow a build of a new idea or design.

I have been in the mulltihulls r/c hobby since 1999 - and into r/c monohulls and big boats much, much longer. A review of those who claim to be builders are NOT production builders, and certainly don't make a living off of what they do build and or sell. If I knew of a viable source of buyers for an r/c multihull, I too would consider myself a "builder" - considering I have done about 6 custom r/c monohull builds for friends, I guess I too could be in "your category" of a "builder".

I know of only one US production company, and to my knowledge their total sales of a production trimaran "might" be 8 units. Ummmm - call me silly but this is NOT a production builder selling his products on a high annual volume. The company MicroSAIL is still considered a home builder. While I understand you want to resist the urge for companies (or dealers, manufacturer's reps, etc.) to post free sales adds when the forum could be gaining revenue......... I am suggesting it might be more appropriate to take a look behind the scenes and see exactly how many boats they are building/selling. I AM a builder/assembler of r/c boats - it's just I didn't add that to my signature line. If that's the problem, why not just email those in violation and ask them to remove that from their signature? Deal with the specifics, not in generalities - it makes it a lot easier to determine if you are referring specifically to me - or the "other guy". The fact that someone includes their background as a big boat builder should NOT play a role in how they are viewed commercially. They may be using their outside job experience to explain why they feel qualified to post a response - position - or opinion.


I now return you to the program already in progress and will look forward to moderators dealing with specific posters - not doing a shotgun approach and including everyone. Just a suggestion to make your reminder posts a little more "people friendly".

Actually, you were not one of those that I had in mind but one member "outted" himself and yet another I suspect is a dealer of not only sailboats but other R/C boats also. One has been contacted through a PM but the other hasn't, ........ yet.
I give most members a lot of space and understand that when they do signup they don't bother to read the site's rules as they assume that all forum site rules are pretty much the same but no, this one throws in a few extras. I'm the first to admit that when I first joined I assumed this also until I took the time to read them.
There are ways to publicize your products if the rules are read and the author understands them. They shouldn't look at the rules as a bad thing unless they're trying ot be sneaky but can also find that it can be a way to get yourself noticed by prospective customers.

OK, where were we?

Happy New Year to you all,each and everyone ! from Tricat. I know in the northern hemisphere we
are all a bit hazy and sleepy,but 'tis time to get your thoughts on track for the coming year?!
Does the southern hemisphere have any feedback for us to look at or read about yet ? myself?
a doodle on paper re autogyros[electric models]and their mysteries led me into the realms of aeronatics again.There it was,for a flat sheet,a camber at 40% of chord of 4% chord will give a very fair shape on model aircraft.Mm-mm-m ! Our sails are small and are a flat sheets,was this the info required for my question.why do flat sails work very well in calm conditions when fitted to a multi?
Well it is January,bags of time to design some more sails ready for the warmer weather.
OK that's all for now.Regards Tricat

Flatter sail on a multi since you need speed, not power to push lead through the water. Also less camber for wind to move across. On the other hand - waves, medium winds, add camber and power up the sails. Once you get into the wind speeds of just staying upright, flatten them again to reduce the power. Kidnd of rule of thumb, and somewhat influenced by leadfree sialing on a multi. Same goes for ice boats - flat sail = fast !

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< Message edited by Justaddwata -- 1/2/2008 7:44:38 PM >