After dedicating some time to the Internal Assembly options, I told myself that this model could be also equipped with a Reverse Bow similarly as done with the Esterel-Footy. The transom is also sloped. These two features should offer a lower weight for the hull.
In the Class M is important to save some weight from the hull to be transferred to the bulb and avoiding total weight increase. Further the reversed bow should offer better water penetration and retarding the nose down.
Since was my time for modifications, I have also reversed the Fin shape. It is an advantage to reduce the chord length of the fin at the hull attachment in order to reduce turbulences especially when tilted.
I do also increased slightly the displacement to compensate the appendix area and volume reduction while keeping the LCB close to -3%
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The female mold will be of the same type developed for the Esterel-Footy. with two parts. The hull will be a pseudo mono-bloc.
Tank you Alberto !
Here below the Diamond side view and static calculations for the Rig ‘A’ .
A wind of 9.7kt will produce a heel of 30°
A wind of 12.7kt will produce a heel of 45°
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Performance against wind speed can increase slightly by lowering the sail Center of Effort - CE with a Rig ‘B’ with same Sail Area and shorter Mast…
Of course Breakwater !!!
not evident to make a dual mold assembly and to laminate the inner joint line when the access from the bow is very small. The idea of using an inflated balloon may be the only option I’m thinking now !
In attachment the file including shadows to scale 1:1
ClaudioD
Hi Claude
I like very much your last Esterel-Diamond boat and I think, with your permission, it will be my next project.
I appreciate all your work. You give inspiration to many people.
In your last attachment I can’t open the #6 shadow pdf file (DIAM7-RB-S6). It looks damaged.
Can you indicate the correct place of the mast for the swing rig option to ?
Thank you.
Hi Christos,
You were right and I’m sorry for the corrupted file of the shadow 6.
Checked and inserted the correct one.
Thank you for choosing this brand new design.
For the swing rig is not easy to give a fixed figure since much depend on the Main/Jib rationing.
What I can say is that in accordance with my experience, the mast step for the swing rig should stay ahead of the classic one by about 5.5 to 6cm. Now, also the actual Classic Rig position is supposed to be confirmed .
What I can say as general “rule of thumb” is that the Classic Rig Center of Effort - CE shall fall vertically on the leading edge of the Fin. Variation of +/- 10mm may occurs also depending on the jib ratio. The sail plan depicted above call for a jib percentage of 37.5% .
Nothing better then making some trials as part of the tuning.
For what concern my construction, I’m supposed to start very soon. The shadows are already printed.
Fine, the simple arrangement as you know, is to use a stepping adjustment for classic mast step.
In my first Studio, with Swing Rig, I used 3 tubes. See pictures below as off topic
Cheers
ClaudioD
I just read your Thread here on your M-NewPlan. I am definitely interested to see how it all plays out for you now that you have it in the water. Your soft chined hull, reversed Keel shape. Your hull looks very good on the water. It is not generating any hull wave motion, no wake. Im impressed Claudio. Keep the photos and commentary coming as your testing proceeds.
I didn’t see where you listed what total weight displacement your hull was designed for. Can you give the info?
Allthumbs,
probably you are mis-leaded, the pictures above #32, refers to a previous designed Class M of 2005 and called “Studio 3”.
The Studio pictured above have a displacement of 4442g, including appendices.
For the time being, I do have abandoned the reversed keel shape, since from the Reynold number and speed involved, is not worth using it.
Cheers
ClaudioD
That’s a very intriguing and interesting design concept, I downloaded your futinette plans and are following your build on the italian site, looking forward to see the end.
I have just a question, I was wondering if it would be possible to adapt the diamond M concept to the US one meter class, I understand you are in a middle of a move now, but it would be great to see how the boat would look like.
Hi Gio,
it depends on the US 1meter model dimensions in therm of displacement and bulb weight.
As it is, the actual Diamond cannot be directly stretched since, due to scaling factor, the US1Metre will have a dry weight of only 2.1kg.
Cheers
ClaudioD
Yeah, that’s what I though to i tried once to scale a M down to 1m and that was more or less the final displacement, I will not do that “mistake” again. 2.1Kg would be on the light side for a USOM, maybee to light, but it’s not that off.
US1m are a shorter version of the M, light with quite a lot of lead and some what “condition specialized”, as a developmental class there is a lot of variations and opinions . A good all around US1m would have a 2.5/6 Kg total displacement and maybe 2.2 of those (as much as you can) in the bulb. The only limitations in the US 1m rules are the max.mast height (at 165 cm) the sail area (1524 cm2) and the max keel length (36.2 cm from the keel attachment point in the hull).
Hi Gio,
my readings show that some US1 models are ranging around 1.8/2.0kg for the bulb and 2.8/3.0kg as full displacement. 2.0/3.0= 0.66% is a good figure for the righting moment.
On RCgroup it is reported about Hull16 with 1.8kg and 2.77kg full displacement (4lbs/6.12lbs).
I wonder if the 970g left are sufficient for the full contruction. I do not have such experience with US1.
Remember anyhow that volume scaling go with the “cube” of the scale.
You need first to find out what others have done in terms of displacement as such to make your hown decision.
For a US1, you need to draw it from scratch.
ClaudioD
