the good thing about tris is you dont need much wind to have some fun,good luck with your first outing hope she goes well for you mate ,nice job .
mart

hey guys.

over the last few months or so i have been away at sea. and i started desinging a tri i ended up scaling down an exact copy of the B&Q tri (ellan mcarther) i have now finished building it and it sails amazingly well. some of the features include dagger boards on the sponsons which go up and down and so on. shes about 6foot long and 7foot tall from keel to mast. i will get some pics posted soon. but i am temped to make a mold of her now and sell them on ebay. the mold would be available in 2 forms straight from the mold or the hulls glued togher. only probs with the second is the servo for operaing the daggerboards is molded into the sponson so i would have to put these in, i would use futarba standard 3300 or what ever they are.lol. it would also come with a step by step guide to how i did it with colour pictures and a copy of the plans and a few 3D pictures from the plans. i would be looking for around 200 for the straight out the mold and 250 with the hulls gluded. the nearst thing to compare is the F3 which is $2250 in full kit form.

my kit would include;

all 3 hulls
2 x cross beams.(molded archs

extra would be

daggerboards
rudder
hulls gluded including servoss

if anyone is interested please let me know on here i want five deffinates and i will will make a mold. if you all say yes today there would be a 2week waiting. once the mold is built i will offer next day delivery.

i will post pics asap.

cheers matt

what will the hulls be made of poly or epoxy !!.its a bit hard to say yea id like one if theres no pics of the finnished boat or the unfinnished hulls.not sure if your the matt im thinking of whos at uni in fleetwood? if so you kept that one quiet lol.

Hello all!

I found this site while searching for what little there appears to be about RC Multihulls.
I'm in Oregon USA.
I've been building and racing OneMeters for 15 years, and recently (on a lark) decided to try a tri. I used one of my old OneMeters, it's very narrow for a mono but a bit fat for a tri, and added to it. The main hull is glass over balsa strip, the float hulls are glass over foam. I made no real attempt at extreme light weight, the idea was simply quick build and go try it out. One meter long and one meter wide.

The trial rig has 1000 sq inches of sail. These ugly things are only temporary sails as I sort out the rig.
I also have a wingsail I built for a landsailer that I intend to try.

Here's pics (if I can get them to post.)

Just thought I'd add, I've also been building and sailing "full size" boats for 35 years, and currently own a couple of monohulls and a trimaran.
I currently race a Santana 20 and a Tremolino 23 trimaran, in addition to owning a handful of other boats.
-Phil

Nice looking boat Phil let us know how she sails looks really nice .

I finally took the RC trimaran out for its maiden voyage.

All in all I am very happy. New boat usually takes a while to sort out the rig and stuff.
The tri sailed beautifully, it's well balanced and tracks straight, no noticeable weather helm or lee helm either for that matter. Steering is very responsive but not so sensitive it's quirky, the keel and rudder seem about right. The rig is fairly well balanced, but the boat is so light it stops head-to-wind on most every tack. I need to rake the mast aft a bit more, but the sailplan seemed to balance pretty well, but the temporary sails started stretching and blowing out quickly - it was just too windy. Big gusts, was blowing 15 with gusts above 20 out on the lake.
It accellerates like crazy! From a standing start - in 5 feet it's going faster than my US One Meters ever went!
So I believe the sailplan is viable, and will build better sails and it should be good to go.
All in all, a great proof-of-concept. For a one-off "that-looks-about-right" design, it was very good first time out.

Capsized a bunch of times, but as luck would have it we didn't get any capsize on film nor any of the best high speed runs.
Between gusts the wind typically died to nothing, so it was either hove-to during a gust, or not moving for most of the vid shots. Murphy's law of photography, the best stuff happens when the camera is off....

(experimented with posting - can't post a vid and no way to host one...)

Hi guys,Are you all sailing now or what !?Just thought I'd drop a line to see if anybody's there.
I think the way the rain has been coming down,it may be possible to try mild aerobatics like loops and rolls,I do enough inverted flying alreadyso I'll give that a miss.I don't know about the rest of the world but I've seen more than enough rain for this year.My mispent time has been trying to fly a helicopter on the computer !!!?[:-]It's a good job I did not buy one first 'cos I could have bought a full size multihull for the price I would have paid out !!.I have nothing new either built or sailed
since my last writeup,but I check at least once a week to see if there is any more postings.
Stay right way up and Happy folks!! Scotty

Currently back to Michigan. Attending the Formula17 (big cat) championships. Hope to get a few good detail photos for a possible next boat. Otherwise, it's just been too hot to stand in the sun to sail !

Hi DickL,You lucky man SUNSHINE & Multihulls !!!!!! Looking forward to your pics,please try and include shots with sunshine on as I've forgotten what it looks like.
Stay happy !!! Scotty

Photos Just for you Scotty !!!

One of the starts for the F-17 North Americans.
The F-17 - a single handed, uni-rig with Asy spinnaker
Formula 18 - a big brother, double-handed boat (main, jib and spinnaker)

Sunshine, warm water (about 76 degrees) 8-10 knots of wind, waves 1-2 feet. (oh - and lots of beer)

I have been reading thru this thread with much interest- Having been planning on building a Cat for a few years- Started lofting out some ideas last night. It seems the common thread here is Tri's- I am a cat man thru and thru- Pics below is my day job- 70ft long and very fast.

So I want to build around a 1.2 mt cat and really like what I see Multiman doing so can any one out there provide me with some basic cat guidelines based on 1.2mt LOA- even better has anyone got plans for a cat that will perform without all the usual design flaws??, any help much appreciated /) /)...

Had trouble getting pics on from last post -try this.

Dream -

you will probably have to come up with your own lines, since most r/c boats are of the trimaran configuration. Even at 1.2 meters (48 inches) you may find the hulls too narrow to house a winch. It might require a central "pod" and for that reason, many don't build cause they don't like the looks. A builder from the UK had one (and the only one) that I've seen photos of that actually was a nice looking boat.

Just like big cats, the little ones suffer from pitch-pole and over-canvassing. Since you aren't aboard, you can't feel weather hull go light until it's out of the water and too late. Movable ballast is possible, but again, it will be reactive - not proactive. Ad in the inability to back wind the jib easily (you can with a second winch/radio channel) and it probably explains lack of interest or numbers of a cat configuration. I started on a 1/2 meter of my own cat, but got disillusioned with trying to make it "look nice".

These two from Australia.


And two from US - mine has the pink wing-mast.

Dick, thankyou for the heads up, I see the limitations of rc cats but wonder if I can build beam wide enough to house gear (and balance) in both hulls. Which brings to mind the question of beam vs lenght and achieving a nice balance of aesthetics and performance. When you talk of difficulty of backwinding jib I assume you are talking of the trouble getting cats "out of irons" ??.

Hi,Dickl,Thanks for the pics,they are so good I;m going to sit looking at them to see if the sun rubs off????.I would like to throw an idea to you,but need some time to get it together re the cats.It should work?????if the tri mods are anything to go by.Remember me saying about the video of my test bed tri having difficulty tacking?By using a simple ploy it now spins like a topin most conditions.After seeing your third photo showing the whole cat,the idea floated across my mind,it is using forces available when going into the tack.I'm pushed for time right now so I'll come back to the idea soon.Regards Scotty.

Scotty - am anxious to hear your ideas. Will be standing by until you have time.

Dream - actually on the beach cats, the boat starts into a turn to tack, the main is released (and traveler in heavy wind) and the jib remains cleated. After the bows cross the eye of the wind, the jib is uncleated and is allowed to flop over to leeward side. This slight delay helps "push" the bows over to the proper side and helps prevent the dreaded "irons".

Once the jib is sheeted, I usually bear off a few degrees, "SLOWLY" sheet in the main as the boat starts to move, I then start to head up. I think some problems with tacking can be directly related to a tiller movement that is too quick and fast - putting on the "brakes" and also of sheeting in the main too fast which weather-vanes the boat. A long slow turn and footing off usually is needed to get twin hulls to tack. Often the new cat skipper thinks he is on a monohull, throws the tiller across and wonders why the boat stops dead - and in irons.

If one also considers the lack of lead keel/boat weight and the loss of momentum happens pretty fast too.

Will be interesting to see/read TRICAT's thoughts.

To add to what Dick L has said about Tacking, the idea is to 'drive' your boat through a tack, judging the speed and the amount of rudder you can use without stopping the boat dead in the water. Use around fifteen degrees of Rudder throw on each side and that should stop the 'Braking' effect. It will only come with practice, and depends on your boat design too.

When tacking my MINI40 CHEETAH cat, you can literally just let go of the transmitter and the thing will find it's own way through a tack when in irons !! Most Multis I have ever used will tack on there own if the sheets are tight in !! The trick is to encourage it to go on the one you want !!

Multiman

Hi Dick L,Hey you've brought the sunshine,thanks DickL!My solar powered brain may work now?To throw my penneth of info on cats into the ring.Things that came to light in the testing of cats were the following. 1 If the hulls had little rocker they were very reluctant to tack.2 conventional rig with big jibs also bad at tacking.3 choppy water causing wave slap as you start to turn cancelling most of your speed and penitration during the attempted turn.In answer to No 1more rocker did work better,but was not the complete answer to tacking.My thought on this is based on triming out my marblehead yacht.Set the transome down by about 3mm and rake the mast about 40mm back.As soon as the wind blew the transome rose to above water level and the mast became vertical,ideal.Maybe that if the cat was trimmed so that it took most of the weight in the back 2/3 of the hulls when in flat calm water.when the wind drives it the hull will push the nose down to let it sit at the correct angle in the water.When you tack the drive stops and the bows will rise reducing the
the sideways area of the hull the further forward you go,in otherwords reducing the moment arm length of hull that is dragged sideways.??!![:-] As for No 2 consider this fact as you tack with a conventional rig the main depowers as you turn because it moves downwind.The jib does the opposite,sounds good the wind must increase giving more thrust?Not so,for a split second it does but then it becomes nearly at a right angle to the jib killing all drive as well as trying to drive the hull back down wind.So a small jib is better on cats[models].You can of course use a swing rig because
both sails depower and only offer the drag of the rig which is nearly head to wind anyway.As for No3
All boats suffer this sometime,if you get into irons it's just a question of letting you boat get moving in reverse,letting your sails fully out and putting in full rudder left or right as required.Most times
the boat will swing round easily then pull your sails in and away.!!???Those are my thoughts
at the moment based on books and testing out ideas,it's just that cats present quite a challenge
I think Multiman may have more info on them,but I think he maybe on holliday at the moment.
Regards Scotty

Hi dickL have just picked up your reply.Yes I agree with both yourself and Multiman.The cat seems to want constant sailing when tacking,when you are on board its alot easier,being able to back the jib
on demand,on models it means adding weight to do that.As I said Multiman should have more info about cats,I have seen his sailing,very nice it is too.Regards Scotty

As a captain on performance 70ft cat and owner of fleet of rental hobies I too have had plenty of experience in getting the nose round and watching / teaching others to do it- it is certainly more difficult on smaller beach cats mainly as you don't have the weight/ boat speed to get you round- not to much of a prob on a 17 tonne cat but still can occur.

The key points in a successful tack are cerainly- choosing your wind shifts/gusts, choosing the right wave to go on, keepings momentum up thru smooth turning, releasing jib at optimum time and leaving main close hauled thru tack ( I guess not possible on a model as the main and jib sheets are usually working as one) and probably most importantly when in doubt, bear away a little ease out sails a fraction for a gain in boat speed then bring it back on wind while sheeting in and continue thru to a tack before you lose that liitle boatspeed.

All sounds easy on a big cat- looking forward to giving it a shot on model- which brings me back to where I was a few posts ago- I understand that hull shape is not as important as sail setup- mast placement- trim and skipper expertise...but what I would like a recommendation on is what approx measurements should I be looking for on a 1.2 mt cat ie..what hull beam at widest point, what overall beam of cat, mast height??, with these basic cluse I could make a start buildinga couple of prototypes with foam and epoxy.

Or should I build something with a little more LOA??, any help much appreciated

Dream -

there are three international size classes of multihulls most commonly built ...

1. a 1.2 meter MINI40/F-48 size,
2. a 2 Meter size and the
3. 1 Meter size ........... is quickly catching on.
Staying within one of these will result in a boat that can be raced, and will probably be sellable.

All are development class boats, and the F-48 has the least restrictive rules of the bunch. Speaking of this size, the class allows 1.2 meter (48 inches) length maximum, 1.2 meter width (48 inches) maximum, 2 or more hulls, and .93 sq. meters (1400 sq. inches) of sail area maximum. Working within the very unrestriced size rules, you are free to build what you think is fast. The MINI40 Class has a few contradictory rules, and the 1 Meter is similar to the F-48, except for size.

The 2 Meter class is obviously a bigger boat and the main difference in rules (and size) is the the 2 Meter class has a maximum mast height, and sail area is unlimited - just opposite of the MINI40/F-48 mast/sail concept.

I originally started with a NACRA 18 Square (see photo) as my base boat - 5.5 meters (18 feet) long, 3.35 meters (11 feet) wide and 18 sq. meters (194 sq. feet) of sail area - main only - no jib. This "real" boat gave me suggested scale sizes for my first r/c model. The hulls are approximately 0.076 meters wide hulls x 1.2 meters in length. (3 inches x 48 inches) You can start there, and most drum winches will fit inside the hulls. Arm winches won't.

I suggest corresponding with MULTIMAN as he has experience in production and sales if you are thinking of going that way.

Dick,

Thankyou, very informative- not sure if any of these classes are operating in NZ but will do some research.

Still sure I will go the 1.2mt size as this size fits in most vehicles with ease (have found this is optimum size in my RC powerboats for transportation.

Will build at beam at 85% of LOA (thankyou Multiman for heads up on this).

Unsure of sailplan and mast height /rig but plenty of time to work thru this issue.

The thing that really troubles me is the instability of these model Cats.

It seems having read thru forum that the the biggest issue with these boats is preventing pitchpole .

So if built to scale against say the 70ft version I captain, then I would need to have a model that weighs many tonnes to provide the required balance.

On the otherhand if the scale model was based on say a nacra then the scale weight could come right down- but of course small performance cat's absolutely require a crew on the windward rail to acheive high speed and balance.

So this got me to thinking the only true way to replicate any full size performance cat is to add ballast on windward rails.

This could be done with a third servo and is the way I will build.

With respect to sales and production- we are a family boatbuilding business(full size) and think it would be great to have a product to sell- people do think our power hulls are pretty special( we tool up and build productuion moulds for all our rc boats) however, whilst we have dabbled in selling the occasional hull and deck, we will not put a website online until we are 100% happy we have ironed out all issues with design and build.

Once again - thankyou Dick - it would be fantastic to have a f48 class down here- hopefully we could make it happen.

One of my "mentors" who was instrumental in helping me set up the F-48's up here is Alan Hayes. Alan hosts the Kiwi website and offers a forum that seems populated by some of your fellow countrymen. Alan has a wonderful looking/sailing GHOST TRAIN (currently up for sail) and there are a few other Mini40's (same size as the F-48 at 1.2 meters) and also a group on the multihull forum that are into 800 mm size smaller trimarans. As for cats, as mentioned, not many of them around - anywhere!

Here is the forum address and from there you can get to the home page, and then a contact page for Alan. I am willing to bet he will be helpful to you too, and can fill you in on the interest in multihulls down there.

Good luck !

[link=http://kiwitalk.radioyachting.com/phpBB2/viewforum.php?f=12]Kiwi Radio Yachting[/link]

Hi guys It's tricat !Bit of interest for Dreamwakes.In John-Shuttleworths write ups on one of his multi's called Nai'a[30ft]He describes how they looked at things to improve performance.Like Taylors tank tests for hull length/breadth ratios.It is only a small write up but it gives you an insight
to what to look at.Just type in the following '30ft trimaran Nai'a' then click on the heading, '30ft
racing trimaran' for the write up.Regards Scotty