Narrow Deck Concept - NDC

This sketch is illustrating the basics of my New Design Concept

The triggering ideas was the “Weight” reduction of the Hull.

I assumed that since nobody is on Board, no galley needed nor sleeping beds, etc. I could easily play with the deck surface.
By narrowing the beam, another direct consequence was to keep the deck sheer line above the water when the boat is tilted.
Using a Chine hull, I further found that the tilted drawing presented a sort of “immersed vertical wall”…
I told myself that this feature could help contrasting better the lateral “Drift” when Close Hauled.
Of course nothing is proven yet since no models of this kind are in the water at the moment.

The experimental work started with the class M “Diamond” where the principle is applied to a round hull still under construction.
This work is now applied for economic reasons to New Footy designs called : Futynette and Futinett still under construction.
Similarly a couple of RG65 are shortly presented

Any comments ?


Hello Claudio,

I like your idea. Looking at your design it occurred to me that you could push the idea to the limit by reducing the deck height to the waterline (in the inclined position shown). It would be interesting to see the extreme limit of this idea where there is the bare minimum of hull above the waterline. This would certainly minimise the aerodynamic drag of the hull.


Hi Jim
hope will spread around !
You are right, the limits are imposed by the electronics and eventually the servo Arm unless a servo Drum is used !

Good concept, I used a similar design on my semi-v at the transom, sharp v at the bow power boat I designed years ago.
Basically an anti-trip chine, the boat was nearly impossible to flip over thru the turns.

Will be interesting to see how your hulls will work.
Nice job.

Hi Sven,
Indeed the basic form is quite similar but work in the reverse mode on sailing boat. !

this is very interesting indeed as the designs in IOM has evolved to round hulls to chined hulls but the big debate is the angle of the chine, it’s position on the hull and how far towards the bow you need it.

It seems that boats with chine are climbing that little bit higher when beating upwind and accelerate faster out of a tack, while planning quicker downwind.

Glad to hear that you like this idea.
I draw a sketch of the side view to show how the “vertical” surface extend along the lenght.
Modifying the chine segment of the foward shadow it may be possible to extend the “vertical” wet surface, but I’m not sure that will be a wise choice !

The dark blue is the actual “vertical” wet area contrasting the drift while the yellow could be achieved but with wet area increase…

Nothing is certain until the water will tell ! For sure is that the upper part including deck produce a gain on the weight and keep the deck sheer line out of the water and this is already an achievement.

the Lintel is a IOM boat from the UK which works particularly well in a blow hence why they’ve adopted it in Dallas for their Blow out event - you can see why with the distinctive chine. But lacks light wind performance

The Britpop and V8 are the top designs at the moment - slightly different thoughts on the design of the IOM with a chine

some of the Marbleheads and now 10R are also coming to this new design see Frank’s new 10R

RC boats seem to get narrower as they less rely on the withd as their full size versions but to get the volume the chine seem to be the solution

hope you enjoy the links and see the different thinking in the designs


Nice to see similar design approaches, while I ignore the motivations that produced that shapes.

Hi Claudio,

have a look in there as there are some really good articles and in particular look at the December 2012 one where you have the interview with Brad Gibson who is behind the first chine IOM in recent years that really works - chine boats is not new as you know but it is making a come back and for good reasons - to the point where people like me who still sail a rounded hull we struggle in the top wind conditions of each rig whereas they can carry theirs longer and this particularly works in times where the wind swerves on the limit of our top rig.

The example I can give is when myself and another sailor went to the Scottish National champs (see the latest newsletter of Sept 2013) and I struggled at the starts as in Ireland we don’t have many boats so it took me a while to get used to the starts with up to 14 boats. But even when I got a bad start I pretty much always managed to get back to the top but never won a A fleet race despite leading at the first weather mark a few times. I had the pace on most skippers but not on the top 5 who had chine boat design (the britpop) and who historically I used to compete with.

I found the biggest difference being downwind - I simply could not keep up with them they got planning much quicker and were surfing longer than me and lost places almost systematically to them on these legs. Then upwind during a puff they seemed to have more “bite” as I presume the chine is acting reducing the amount of lateral drifting due to the heel and less bite from the fin keel then. Also they were able to stay on their top rig where I had to change to B as the wind increased but with some lull in strength giving boats with the top rig a clear advantage, particularly downwind. Despite them broaching at times in the gusts what they lost was less then what we (sailors who changed to B) lost in the lulls. Also in the puffs downwind they had less tendency to nose dive over round hull designs and as a result they accelerate once they recovered from the initial speed increase in the sails. This because the other design element they’ve done is to move more forward the volume and in particular keeping quite full the volume just in front of the fin so to reduce nose diving whilst still trying to keep a relatively narrow line entry at the bow to help in the light wind (well that is my view anyway but I’m no architect like you).

couple of the guys here in Ireland now have a chine hull design so it will be interesting over the next few outings to see the differences.

enjoy the reading

Interesting Gilbert, I need some time to read all arguments.
What is making a difference is that my New Concept is based upon a full chine hull where the bottom is a real flat surface as wide as the deck and the angles between panels properly selected.
Pity that for some time I could be able to test my design on a Class M since preparing for a big removal. A lot of trows aways & packings.

Are you moving house Claudio ?


While my Lab is empty the PC is still alive and this is my last application of the NDC for a Class M :


Don’t forget to let us know if your email changes.

Off course in due time !
To sell a flat here in Nice it can take 15 days as well 6 months…

BTW, have you seen the Esterel M chine Ver.6 below ? is somewhat lighter since I reduced the draft to 42mm.
Are you interested ?

Yes - I just “found” your last email with lines, and was happy to see the beam down and under the “traditional” 200 mm (plus).

As per our emails, I would like to try a minimal version, and as you know I like the multihull hull design, where there are flat underwater forward sections with transition to a rounded underwater section to the rear. Minimal to “zero” flat deck and basically a “toothpick” with tall mast and deep keel.

I will give a try at building your thin, chine-enabled M hull to see how it performs. I had already thought about lowering the deck height from waterline, so less draft would also be something to try.


PS - if busy getting ready for your move - this can wait. I will compare the sections’ sizes you sent me, to the ones shown in your above Rev 6 sketch.

Hi Dick,
will be difficult for me drawing a mix of flat and round sections changing along the lenght. Shaping a bloc of foam will be better and faster.

With the Classic Rig type A


Apparently, as being reported to me, some RG65 drawing files disappears from various treads
This is a collection of some drawings (ZIP file) about Esterel RG65 various designs evolutions.
I will do the same on other related treads.
Sorry for the occurence, but I ignore the reasons !