Shinobi mini40

Thought I’d share my latest mini40 here. First time I’ve had someone to wave a camera at it! There’s quite a bit on interest in the UK at the moment with one club even running a race series for the mini40 over the year.


Tri sails by ??? (PJ Sails, your own or someone else?)

Thanks for the video, Dick

The sails are my own. Admittedly I’m a bit lazy here and just made them out of single panels and used luff round to get the shape. Main is a bit flat down low but I just wanted to get something together while I’m waiting for my PJ suits to arrive.

That is a fine looking boat! Fast and stable, and you did a good job pulling her out of a potential pitchpole at the end of the film.


Great video clip, the boat looks fast and does not tend to bury the bows. Definitely your foils make the boat more stable.
It would be great if you could post some data on the Shinobi - foil dimensions and position as well as rudder dimensions and the position of your rig.
Keep up your good work!


I’m afraid if I told you that I’d have to kill you! :slight_smile: Best to send the divers down to get a look while it’s on the water…

Not really in the spirit of building class interest then are we.

There are plans out there that are unstable/easy to pitchpole and that is a detriment to building interest in the boats and encouraging less experienced sailors to make the move towards multihulls. Information that can make improvements to the handling faults of model multihulls is an imperative, unless proprietary interests are your personal priority and you like to sail alone.

Thanks, Niel - you kind of echoed my own thoughts.

I know Siri is building/selling for profit - and perhaps this owner isn’t interested in providing ideas to others who may make a profit is one thing - but on the other hand as you note, dispelling the often-held notions about poor handling of multihulls, lack of tactics, etc. certainly don’t serve the r/c multihull community or inspire class growth. Fortunately, Siri not only has multiple designs available, but is serving the multihull interest with free plans seems to reflect what some of us hope the forum would provide… sharing of information.

To each his own, but from a personal perspective (not as moderator) one could easily say …“So What” to the entire post. There are lots of other r/c multihulls - both cat and tri that have videos on YouTube as example - what is one more? As I recall, Mike Friend from the U.K. was gracious and shared video and information on his successful cat design with foils a year or so ago. Maybe competition is fierce there and so any advantage is intended to bring home a new “pickle dish”, but my guess is that the responding post, without much explanation, may have turned off many in the multihull community.

Thanks anyway for the video. Dick

My impression:

Please don´t take him to serious for that kind of respond.
Maybe he was just too lazy to answer the questions from Siri properly. :slight_smile:

I would assume that his Shinobi needs an endplate - which slows his boat down.
Overall performance in a series of races under different conditions is what counts.

Just my 5 cents. :slight_smile:

I would have thought the smiley face in my previous post may have indicated some humour in my reply but apparently not. Much of the internet passes under the ‘so what’ category. I apologise for sharing some good resolution video of a mini40 going quickly!

The mast is bang on mid length. I’ve no idea where the foils are off the top of my head as I only have the measurements from Shinobi #1 and I moved a few things after that boat.

As for endplates on the rudder - I find that if you couple them with float foils the boat manages it’s own pitch considerably better than without one. If the float foils are left to their own devices they will overlift as speed builds whereas the T foil starts picking up the transoms with it - end result is quicker in my experience. The Shinobi has so far proved to be quicker around a course than a current catamaran and a Machete tri.
Float foils are not a one shot fix for all that ail’s ya. Many of the ‘problem’ 40’s I’ve come across are poorly rigged and torsionally flexible and the two combined makes it nearly impossible to fly a main hull without burying the bows as the c/e moves forward as the boat gets more powered up and even more when the floats start burying.

As for multihull interests - I’m interested in pushing fleet racing locally to me and have got 2 people into boats at my sailing club.

Dear aardvarkissues,
Don´t you worry - I got your sense of humour. :slight_smile:

Having shared my own experiences for the last decade in this forum - and others,
I know that´s it not allways easy to stand up with what other people expect of you.
Sometimes they appear offending and as a pain in the …:lol:

Anyway - I believe that guys like Gary Moorse, Siri and I - and also Dick Lemke for example -
have helped to increase the overall understanding of rc-multihulls quite a bit.
For now I think that sharing technical informations and building details are the way to go.
Later on, when we meet at the pond(s) there will still be enough time to act as “opponents” - got me? :confused:

It was not untill I got in contact with certain german modelbuilders (!) that the theoretical
and practical understanding of the involved forces increased to a point where I became
satisfied with their overall performance.
And you know - don´t you (?)- there are a lot of difference between 40´, 60´ or even bigger multihulls
and the behaviour of our little 65cm, Mini40 or 2 Meter models.
There is still lack of knowledge out there!
The amount of impressive rc-multihull-videos on youtube for example has also increased to about 500% over the past three years!

As you may be aware,
my personal goal is a real rc-multihull-worldchampionship with 50 starters at least.
But it still may take another decade to reach that point - I will be 60 then.
Again anyway - got nothing " better" :smiley: to do for now.

By now more than 1000 plans of my own “Nightmare Mk.VII + Mk.VIII”-designs for free download
have been given out to people from more than 20 different countries via my own emailadress and Siris site -
And there are really “exotic” countries/states like Kuwait and Tasmania amongst them.
So there IS interest out there.
And the responds in itself are very interesting.

So sharing technical informations and knowhow can be very awarding in itself.
But it is absolutely up to yourself, if you are willing to go down that road.
From my own experince I only can tell you that I had been looking for shipwrights/ boatbuilding teachers -
who where also willing to share their knowledge - for many years.

And because of their appearent “envyness” I really got pissed for quite some time -
and started to behave the same way.
Then I shifted my own attitude back to the way I was before -
and I can tell you, it feels much better. :slight_smile:

But again, these are just my own 5 cents

Apologies - but the smilie face wasn’t noticed as it was only [ :slight_smile: ] which was overlooked when included in the post - the smilie “image” stands out and is easier to see. [ :slight_smile: ] I would have known then that there was humor attached.

Sorry for misinterpreting.


Dear Aardvarkissues,

I offer my apologies as well as I too missed the smile symbol.

But let me ask you this, without the reactions of Dick and myself, would you have started to volunteer information about your boat or would have left it at the quip?

Would you be willing to provide more details? For example; foil placement, foil length, area, and camber profile (also, symmetric or asymmetric?), depth of rudder and area of the T-Foil, along with an explanation of your choice of these particular parameters and why you think that they work in concert with each other so well?

Since there is such a lack of hard information on the whys and wherefores of the various components that make up a model multihull any light that successful designers can shed will help all of those who are interested.

As Dick well knows, the monohull RG65 Class has grown quickly in the US, as well in the rest of the world, primarily due to the great amount of information that is available to help those interested to get involved. It is not by accident, it is the fruit of the great efforts and commitment to growth and open sharing that the class leaders have sown for years.

A multihull is not a monohull, in many ways it is more of a challenge to build. The tradeoff is exchanging lead for spread, and there are more component parts that have to be designed and constructed into a coherent whole. Improvements in design understanding and the placement of the pieces to make a good boat is an imperative if there is to be any growth in the multihull classes.

Look, in many ways the multihull offers a lot of plus side. It has the speed and acceleration that might attract the youth that looks to video games as ideal entertainment and by shedding the lead bulb allays the concerns of parents for themselves and their children having to deal with a toxic material. These are good things that should be hi-lighted in promoting the class, but more reliable designs will go a long way to making multihulls a more acceptable option.

Yes, I would have but with time being what it is, not until I had the chance to do it properly. The boat lives somewhere I don’t get to it often and as everything on it was placed on a whim.
One thing I’ve learned from sailboats is that you can make anything work as long as you understand its shortfalls. If your foils or rig aren’t in the right place then rake or sail area distribution can be changed or daggerboards moved - This is why nothing is written down for my boat other than what bits were designed on the computer (hulls). The hulls are at the angle they are after test floating at displacement before final assembly. The foils are wherever I decided to put them and then the sails get shifted to compensate if the balance isn’t quite right.

The only things I can tell you off the top of my head is that the T foil is symmetric and on the bottom of the rudder at -2 degrees and the float foils are naca 64310 tapering down to 64308 at the tip as that is what my moth hydrofoil moulds look were milled at.

There aren’t any smiley face symbols in quick reply?

I’ve uploaded a bunch of detail shots here. I’ve not got any dimensions still, but you can scale most of the useful stuff from the photos if you are really that interested…

Suffice to say it was a bit windy for the top suit in those pictures! :wink:

Looking at the photos - may I ask where/how you access the main hull for servos, radio gear and batteries? I “thought” it might be in the low spot directly behind the mast, but the closeup of your vang doesn’t seem to show it having access.

Thanks, Dick

Wow, what a beautifully turned out craft!

I really appreciate that you haven’t had to kill all of us for a few pictures. Although the pictures are killer!

Back to the boat though, are your foils asymmetrical? Do they toe in a few degrees? Very nice rudder linkage and a pretty small T-foil rudder to my eye. Do you change rudders for different wind conditions, a larger T-foil for brisker weather? Very interesting bearing gooseneck, using the mast as the axle. I designed and used a similar one on my conventionally rigged 36/600 (an American Monohull Class) before I switched to Swing Rigs. I thought it a pretty slick design element and yours looks very professional.

Shinobi is obviously well molded, will you be making hulls available? Have you any interest in publishing plans?

All in all a very well engineered Tri from the looks of it and the video shows her at her best. Have you had her in any Spring contests yet?

I haven’t really decided about supplying boats yet. I only have moulds for the hulls and foils as it stands and the crossbeams are a pain to make. I will do a set of plans but I’m afraid they probably won’t be free!

Dick, there is a patch there for the winch/receiver and if you look closely you can see it in this picture:

The servo is under a patch behind the aft beam.

I’m yet to sail this one in any event’s but I have sailed the previous one at an open at Gosport where it won a couple of races. Most of the hardware is from PJ Sails including the gooseneck and head fitting bearings

Thanks for pointing it out. My first (and a few thereafter) views didn’t detect the very slight folds in fabric patch. I think the boom shadow added to pull my eye away. Nice rudder linkage system/idea too, by the way. I’m not too far along to cut out my main hull stern and fit similar. I like it because it looks easy to access and adjust. Mine was going to be inside with servo - but yours looks much cleaner and easier.