Thank you for the info.
Michael
some news about the fin and trunk integration ,
cheers
Claudio
Hi Claudio
How do you align the fin fore and aft. Said a different way, how do you align the chord of the fin with the centerline of the boat?
Thanks
Don
HI Don,
First I put the hull on her support, see drawing. I then measure the LWL heights as such to keep the boat aligned longitudinally.
Trasversally I use a Water level .
When all that is done, I introduce the manufactured trunk and adjusted to the previously cutted window in the hull bottom according to the drawings.
The trunk is then glued with epoxy charged resin and to ensure the verticality, I introduce the Fin with the bulb to acts as a pendulum and by gravity ensuring the trasversal alignment, while the longitudinal alignment and verticality of the fin is ensured by pushing the bulb with an heavy bloc (see lead) as such to verify it with a 90° corner.
The second question ‘how to align the longitudinal fin profile with the hull centerline ?’
Personally during the manufacturing of the master mould I mark 3 dots using brass spike heads following the frame drawings , one for the rudder stock and the others two for the fin trunk. Once the hull is laminated, the points are reconized by the marks left by the spikes heads.
Another simple method is to measure the perimeter of the hull at the frame position where the trunk should be located and then divide by two to find the center line. Normally I use a simple paper ribbon , folded in half and mark the bent.
Repeating this operation at various places, you get a serie of marks trough which it is possible to trace the centerline.
The fin cord is aligned vertically on my drawings with the major bulkhead section represented by the summit of CoA. To do that, I take the Curve of Area positioned and stretched between the extremes of the water line in the hull. The vertical line start from the curve summit and shall cross the fin at 35% of the cord while the CG of the bulb shall fall some mm backwards depending on the loads positions.
Hope to have provided the answer you ask for.
Cheers
Claudio
some additional pictures .
Hull filled with water in order to check the inner displacement, the external volume will be some 30 g more because of the skin thickness.
The new bulb of 650g.
Total expected weight should be 1175g with 650g bulb against 1182g calculated ( 1050g + 102g + 30g = 1182g ) - 102g = appendices
Cheers
Claudio
in the pictures is visible the multiple mast support.
Four carbon tubes that will accept either classic and swing rig.
The most recessed 8mm tube, close to the fin trunk, will be used for a new type of sail plan where the jib is representing 50% of the total sail area ending up to the mast top as the main.
In the RG65 nothing forbid to have a tall jib as the main.
The 2 fin/bulb are paint drying
Cheers
Claudio
These are two of the 3 sail rigs that I will test. The missing is the swing rig already used on the CD65.
Notice the mast step position that change as fonction of the rig CE , the swing rig is further ahead - this is why there so many vertical tubes !!!
Cheers
Claudio
a couples more !
I just prepareing for the Deck manufacturing
Cheers
Claudio
the work is progressing, actually dealing with the deck preparation and some accessories under !
In particular the second picture refers to a lamination employing carbon / kevlar of 165 g/m² and glass of 105g/m² - this material showed to be too heavy.
A new lamination (3rd picture) was done using carbon/kevlar of 65g/m² obtaining a deck cover of 20g before bonding.
Cheers
Claudio
some more for today !
ciao
Claudio
Hi Claudio,
Do you find any final weight difference between carbon/kevlar mix cloth and using just plain carbon cloth?
Its just that I always find that Kevlar requires much more resin to wet it out…
- Therefore it might be heavier than using a pure carbon cloth.
I know that I am splitting hairs but it might make a difference, especially on the bigger components.
You must be quite happy with it as you wouldn’t use it, I just feel that maybe pure carbon might be lighter still!
I just thought I’d ask…
Cheers,
Jim
Hi Jim,
for a 120cm hull , I would suggest 2 layers of carbon at 93g/m² and 1 layer of kevlar in between of 70g/m².
Why kevlar ?
Simply because the carbon is relatively fragile against shocks, therefore the kevlar, either in between or as internal coat, will acts as a damper or shock absorber.
Remember : the kevlar never outside !!!
Cheers
Claudio
PS :
2 OT pictures of my Studio2 class M 129cm long :
- Notice kevlar is inside
with reinforcements
Just back to the Topic.
This is the new rig design composed of 2 swing rigs. Not yet made, but the idea behind is to try to get read of the mast interferences.
One of my foggy ideas, could be the one where the mast may also rotate/swing too of some 25/30° under the swinging boom pressure, but this will be experimented later or… never !
This prototype will go under assembly as soon the ordered material will arrive
Any comments or suggestions ? Thanks
Cheers
Claudio
Hi Jim,
for a 120cm hull , I would suggest 2 layers of carbon at 93g/m² and 1 layer of kevlar in between of 70g/m².
Why kevlar ?
Simply because the carbon is relatively fragile against shocks, therefore the kevlar, either in between or as internal coat, will acts as a damper or shock absorber.
Remember : the kevlar never outside !!!
Cheers
Claudio
PS :
2 OT pictures of my Studio2 class M 129cm long :
- Notice kevlar is inside
with reinforcements
fairing / filleting the Bulb-Fin joint with loaded epoxy resin. The blue plastic film is used to isolate the Bulb from the Fin.
Claudio
Here we are ! I think that this is the first time that such arrangement is done ! It will work ? who knows !
This is the double swing settting. I just found out that I miss the additional fairlead for the main boom of that configuration. Nothing is fixed yet, the sails are not made. Even under that configuration I will employ the 100% mast height for both main and jib . Both sail will have 1250cm².
The last picture shows the gap betwen main and mast. In my opinion the mast ‘should not’ intefere anymore with the main luff , obviously need to be proven yet !!!
Cheers
Claudio
hi Claudio,
great job as usual !!!
What about a wing sail as brand new america’s cup winner ?
I’ll be back soon with pictures of the Open 60 construction.
cheers,
Paulin
Hi Paulin,
it is not escluded, since the RG65 is an Open Class. Something can be borrowed from the land sailing.
Actually I want to try a sail plan with 100% height for both sails and splitting the surface at 50/50.
At the same time I want to check if it s possible to reduce the typical mast turbulences and get higher speed.
The idea of using a double swing is challenging my curiosity, we will see !!!
Ciao
Claudio
Claudio,
What about using an “A” frame of smaller diameter spars to hold up your sails. Each spar would be mounted near opposite gunwales and connected at their tops. Since your mainsail swings aft of the mast in your current set up you would be able to have a few cross members at intervals bridging between the two mast spars to help keep them rigid. As far as windage is concerned any advantage would come from reducing the diameter of the spars employed to a minimum. An arrangement like this one would get the “masts” more out of the flow over the jib and main than your current set up shown above.
No idea Niel,
I did not even thought about, for the time being I stick to my idea, in future perhaps, why not . If you do something like that let us knows !
Cheers
Claudio