"1290" Class M Hard Multi Chine Hull

The Springtime is coming !

Is time for me to return to the Models construction after almost 1 year stoppage due to recovery from hernia operation.

A lot of thinking and discussions about pros and cons for hard chine hull performances.
I just drawn a new plan for a Class M and there is only one way to verify it.
Here the picture about.

Among this design, it happen to discover various painting decorations methods, like “stretch adhesive film” often used for car body, “Hydrographical paint” with plenty of subjects and “Swirling paint”, my preferred.
On You Tube plenty of demonstrations simply using above key words.

The M picture is the result of a screen shot made on one of YouTube short film.


Just a link out of many : https://youtu.be/nAmvavELsFw

It may be of interest to watch this video : https://youtu.be/_CA0DR4GSQg.
I will build my basin with glass-epoxy 150/160x50x50cm to dip the M hull

What a fantastic way to paint a hull. Will look forward to seeing your progress with this concept.
Of course you do realize that there may be many model boat builders that will now get their hands dirty with “swirl”. LOL

Glad to see you active again Claudio, I missed seeing your drawing and building activities.


Hi Clark,
I’m just designing a basin support box that can be dismounted with the use a swim pool film. Unfortunately living in a flat I’d chosen the shower and missed the bathtub. Easy to put it back to the garage when not needed.

Booth methods are interesting when I refers to Hydrographic painting and Swirling painting.

For what concern the Class M model I changed from 5 to 6 panels chines because the draft and beam are smaller at 30° of heeling.
BTW, the Hull Wet Area is very close to the one with round Hull.

Expected more stability.

Another simulation of swirling paint


Six panels chine shadows are cut and ready to be fasten with samba stringers

Progressing with the template drawings in order to cut panels and successive bonding.

Additional pictures as per today.

Not happy with the bow area, some rework could be necessary.

Samba stringers used to better protect the balsa sheeting corners.

Next sanding work and filler before coating with Glass/Epoxy for reinforcement. Similarly the inner side between shadows.

Hard rain and wind outside !
Sanding stringers taking care around the chines corners in order to keep the smooth and linear profiles on booth side for symmetry. Not easy job !
Some believe that hard chine hull are easy to develop, I can tell that is not true starting with the drawing plan and search of developed surfaces.

Interesting to note that the minimum draft is obtained at 12.5° with 42mm and flat bottom.

Next I need the soft filler to repair some defects close to the bow area. This mini problem is due to the fact that I used balsa sheets of 3mm thick where the widths close the bow are rather stiff. Employed 3mm balsa to avoid flexibility between shadows separated by 121.5 mm, but not always it help…
Next time I will use plain balsa bloc and shaped.

Last pictures below.

It’s soooooo! good to see you back at designing and building.

I look forward to your posts because your explanations and illustrations are different than most. Your excitement shows through your excellent knack for photographing your work. I have, in the past had a photography business and was from young age very interested in the art of photography, so I think I know great work when I see it. Believe me, your photography of the projects you work on is on par with your design expertise.

Keep up the exciting work and the sharing with us your passion for designing and building RC sailing models.


Very kind of you Clark.
In the past I was very keen to use my camera.
I’m of the opinion that a clean drawing and an image are replacing 1000 words !

Further work with filler the same used to repair plaster wall. Easy sanding !
Some additional images showing the bow problem ! Regularity of shape profile, similarly will be done on other chine corners although eyes view will be sufficient !

Progressing, rocker rectified, general sanding, support legs added, fiberglass 85g/m² tissue precut.
Legs needed to keep the hull above the plan to allow fiberglass epoxy lamination without interferences.
see pictures :

Coming along nicely Claudio.

Some questions occurring to me when i look at the reverse sheer of the hull shape:
I was wondering if you were going to split the hull in half in order to remove the fiberglass epoxy lamination from the mold? Perhaps because of the thin hull surface you will be able to “flex” the hull off the mold? Perhaps the reverse sheer is not as pronounced as it looks? Or maybe you’re just going to tear up the mold in the process of removing the laminated hull?

Watching your progress with enjoyment.



Hi Clark,

the reverse sheer is not very important it should not present problems. The fiberglass blades will help a lot.

So tomorrow I will laminate the mold. 24hours later defect correction if needed.

Once the mold is ready I will start the hull lamination with 3 layers of fiberglass of 85g/m².

During polymerization I will cut the female shadows at 11, 9, 7, 5, 3, and A positions used as hull support.


Two days of heavy rain and RH above 80%, thus no lamination until this morning.

External lamination completed, today internal brushing with Epoxy resin…50 pictures up to now !

Next I will use spray primer and soft sanding to remove tissue rugosity before applying packing tape.

The white small pots filled with lead shots are used to keep the hull standing-up vertically

Hi Claudio -

will all of those ribs/stations stay in place when done, or is there a plan to remove them. Obviously if using as a plug to layup plain glass hulls, there is no need to lighten the weigh of the plug.

Nice job - looks great.


Hi Dick,
all the remaining parts of the shadows remain in place, no need to remove them since participating to the strength of the plug.

Surface filler all over the glass coated hull.
Only for dry conditions, no water.
This filler is easy to sand and used to remove rugosity before applying packing tape.

My preferred activity : sanding !!!