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Duo 900 Italy

 

Hi Bernd
?
Added new photos on the work of the DUO 900 Italy.
It has been like spring here for a week and I have also worked on the DUO.
January and February I was unable to work on the boat and it was a cold winter in my part of the country.
?
The second hull is already fully positioned and must only be closed ...

/g/K-designs-Multihull-Sailboats/album?p=Taken,,,20,1,80,0&jump=1&id=256248

BYE
 

Ciao Domenico

So, you are experimenting with a wing mast. Very interesting. and success
A question why did you changed the bow UW section? I am afraid this will generate a lot of
disturbance and water resistance.?

Cheers

Bernd
 

Hi Bernd
Yes, I'm building the wing mast.
I made a 400mm x 300mm x 140mm section
With the spruce strips this section weighs about 900gr
I used 4mm okume plywood instead of the central band and 130mm x 8mm always okume.
I managed to fold everything, now I am preparing the 12m long plan to build 11m long mast.
?
In the next days I will make a section also for the mast KD122 but having the two ends the same.
?
For the bow, there will be no problems since I have not encountered any problems with the KD 860 ;-)
 

Hi Domenico

Do you made any calculations for these sections? The main ligger how we call the part of the biggest thickness (baout 30% of the corde) I have no idea were your Ligger is mounted. He is in any case to weak. At least you have to add stringers from 25x25mm (spruce) that you get a? I-ligger.? What do you use for the covering. Whit this dimensions as you mention you need UD (E) glass and carbon UD for enough strength, Plus some glass cloth to finish the layup. Will you apply it in vacuum or by hand layup. To be optimal the matrix should have a relation of at least 52 % glass i.e. carbon and 48% Epoxy. The layers should be added within 18 hours? to get a chemical connection between the layers.?
To the bows. I do not know how you will make these from the DUO 900 as you dit and your KD 860. I add two photos to compare.
Bernd
 

i Bernd
I am following the project files present here on the forum.
Of course now I am also waiting for other more experts and together with you we will evaluate what to do.
Do you mean spruce strips 25x25mm along the vertical of the two sections?
?
ps some photos of the kd 860 la. The bh 0 has not been touched but a 250mm forward piece has been added, same thing for the Duo 900.
If you want you can bring everything originally.

kd 860 italy 3.jpg
kd 860 italy 5.jpg
kd 860 italy.jpg

 

Hi Domenico
Okay, when you finalize the bow as on the KD 860 then it is okay.?
Here a sketch what I mean to make from the main ligger an I-beam

Cheers

Bernd
 


Ciao Bernd
posso chiederti come migliorare la sezione del wing mast. I listelli 25x25mm guardando le due foto come devono e giusto?
E altro da aggiungere per migliorare la sezione?
Grazie

------ Messaggio Originale ------
Su Giovedi, 22 Apr, 21 At 14:46, Bernd Kohler<ikarus342000@...> da:

Hi Domenico

Do you made any calculations for these sections? The main ligger how we call the part of the biggest thickness (baout 30% of the corde) I have no idea were your Ligger is mounted. He is in any case to weak. At least you have to add stringers from 25x25mm (spruce) that you get a? I-ligger.? What do you use for the covering. Whit this dimensions as you mention you need UD (E) glass and carbon UD for enough strength, Plus some glass cloth to finish the layup. Will you apply it in vacuum or by hand layup. To be optimal the matrix should have a relation of at least 52 % glass i.e. carbon and 48% Epoxy. The layers should be added within 18 hours? to get a chemical connection between the layers.?
To the bows. I do not know how you will make these from the DUO 900 as you dit and your KD 860. I add two photos to compare.
Bernd

 

Ok perfect I will procede in the same time i send you this new photo

20210423_115943.jpg

 

This looks perfect.?
Bernd
 

¿ªÔÆÌåÓý

hi all
sorry for my underknoledge but ?what is the espect life time of wood mast?
stephane b.?
montreal canada



--
stephane blanchette?
montreal canada kd860
 

Hi Domenico - this looks good - my only comment would be without doing the maths (take me too long to remember my 4 years of structural training of 50 years ago and not used since) would be that I would make the area of the vertical wood at the back of the rear trailing edge proportional to the verticals at the leading edge based on their distance from the cross piece.
 

Infinity if you manage and prevent rot Less than one year if you don't - sorry that's cheeky but not far from true.
 

¿ªÔÆÌåÓý

Thanks?
For rot? ok
But more from mouvement of the mast wood -epoxy-fiberglass-carbon

A know from my old sailboat mast have lot of compression on one side after other side? and from front to back

Sorry not be very clear my english is not the best

In french
"Fatigue de materiaux "


Envoy¨¦ depuis mon appareil Galaxy





-------- Message d'origine --------
De : "Ivan via groups.io" <Ivan@...>
Date : 2021-04-25 15 h 22 (GMT-05:00)
Objet : Re: [K-Designs-Multihull-Sailboats] Duo 900 Italy

Infinity if you manage and prevent rot Less than one year if you don't - sorry that's cheeky but not far from true.

HEV_1614602334495.png
-307155435_sc_139903.png

 

This is whay I always work with US carbon and UD glass material. The DUO 800 plans owner will have my mast drawing. There I give the built up system with carbon und glass to compensate for the changing loads from compression and tension.
Bernd
 

On Sun, Apr 25, 2021 at 09:22 PM, Ivan wrote:
Hi Domenico - this looks good - my only comment would be without doing the maths (take me too long to remember my 4 years of structural training of 50 years ago and not used since) would be that I would make the area of the vertical wood at the back of the rear trailing edge proportional to the verticals at the leading edge based on their distance from the cross piece.
Hi Ivan
?
You could make a drawing to understand better.
We are here to improve the wing mast section.
Thank you
 

Hi Domenico - see attached

WingMast.pdf
WingMast.pdf

 

Thanks Ivan
?
Then propose a crossbar along the entire mast.
I am not a technician but building this mast with all this central section becomes difficult to build. To build you must first make the central part then insert in the front and close everything on the rear strip.
?
Bernd's photo is easier to do because you are able to insert the central crossbar and close as you go on to the end ....
With this I am not saying that I don't want to do your idea but I have to understand how to set the work on 11m of mast ....
?
When I made the rudders of the KD 122 Italy I had built the blades differently by first gluing the central strip, then closing the two ends and finally rounding everything ....
?
See this folder? ? ? ??

/g/K-designs-Multihull-Sailboats/album?id=185822
 

Domenico,
If you add a 12 mm cf tube at the rear and glass this in properly you can cut it open at the back for the sailslides to slide up and down. Just ensure that the left and right sides of the mast is glassed well under the tube so that it does not split open.
Cheers
Philip Malan
On Wednesday, 28 April 2021, 01:33:54 SAST, domenicodispaldro@... <domenicodispaldro@...> wrote:


Thanks Ivan
?
Then propose a crossbar along the entire mast.
I am not a technician but building this mast with all this central section becomes difficult to build. To build you must first make the central part then insert in the front and close everything on the rear strip.
?
Bernd's photo is easier to do because you are able to insert the central crossbar and close as you go on to the end ....
With this I am not saying that I don't want to do your idea but I have to understand how to set the work on 11m of mast ....
?
When I made the rudders of the KD 122 Italy I had built the blades differently by first gluing the central strip, then closing the two ends and finally rounding everything ....
?
See this folder? ? ? ??

/g/K-designs-Multihull-Sailboats/album?id=185822

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