Hi Claudio, regarding the keel box I see you’re laminating carbon to wood, another weight saving option is to make the keel box from wood, then wrap wood it in plastic tape and then laminate over it with final peel ply covering over the laminate to give good bonding surface to the hull.
Once cured you just need to slide the wooden keel box out from inside of laminated keel box & no wood (weight) just my 2 cents worth.
Love your deck alignment tabs to hull …very slick !
Cheers Alan
Yes of course Alan, but my design about the Fin Box is that this element is also a support for the servo arm plate.
With a drum servo the laminated fin box is a normal choice since all loads are taken by the horizontal beam.
With the box lamination there is an aspect, often ignored, since a glass laminated box is also a source of leak because of the glass porosity and at the end it may happen that further laminations and paints are necessary to avoid leaking and at the end the gain in weight will be very marginal.
In my previous post I was discussing the increased displacement margin after volume measurement.
With this margins I do not consider necessary a laminated Fin Box . Personally I believe that a wooden reinforced structural box is stronger and more reliable.
For an RG65 I should consider another option !
Cheers
ClaudioD
Claudio, Exiting your engagement to explain and to demonstrate your ideas .-:idea_125:
I too - perhaps - understand 
Cheers
GINO
Ciao Gino,
I try to be as clear as possible and when words are failing I use drawings !
Cheers
ClaudioD
I was a little lazy in the last days !
I was playing with the foam searching for the hatch shape. Personally I like the 3 and 4 !
Dealing with Fin Box !
Inserting 162g/m² glass reinforcements inside the hull !
Next will be the cutting out the fin box slot in the hull and mounting !
ClaudioD
PS : the box is now Red
The Hull weight increase !
1 - Hull just molded = 157g
2 - Hull with stripes = 165g
3 - Hull with glass reinforcements = 218g
4 - Deck with stripes = 125g
Projected hull deck assembled = 360-370g
ClaudioD
Claudio,
Back from the dreaded surgery and I’m likeing what I see; if you’re thinking of running a poll for the final (ish) deck & hatches etc, then I’d definately vote in camp 3 - to my way of thinking / visualising the aesthetics win over each and every time I look. Although of paramount importance would be the attachment & waterproofing systems utilised and of course how effective that then proves to be…
Surgery was considerably longer than anticapated (4 1/2hrs v 1 1/2hrs-2hrs) which resulted in a few extra nights in hospital (not pleasant, especially when you can’t find your earplugs and you should have left home 20mins ago!). So, anyway I’m really hoping to start making some serious progress with ‘Enterprise’ in the next few weeks once I’ve got the complexities of the sitting and/or walking thing back to (hopefully) some semblance of a poor impression of said activities. Ho Hum…!!
Back to the proper stuff now (apologies if I appear to loose the thread at times, I’m currently ‘enjoying’ large quantities of powerful opiates so I’ve been known to wonder…)
Anyway, in terms of timescale, when do you think the first onetwothree sailing trials may be taking place?
Regards,
Row
Wishing you a speedy recovery Row 
Row ,
I’m so glad to ears you back !
Please get some rest and be patient for a while, everything will come better then before.
Cheers
Claudio
About slot and Fin box !
ClaudioD
PS : the lateral profile of the hatch forms. From top I like the 3 and from the side I like 2
Preparation for the Fin Box alignment and preliminary bonding with the help of mounting tool.
The fin alignment can be seen with the lead cord and fin edge while the water level is verifying the transversal orthogonality of the hull.
ClaudioD
Another step with picture 250 . This is the bonding of the Rudder trunk lower part. Upper part will be completed once the deck is bonded.
Claudio
Claudio & Alan,
Many thanks for your kind words, as ‘things’ improve I’m finding it increasingly frustrating - feeling a bit better but not ‘allowed’ to do stuff: three whole months before I can drive again, etc etc…
Anyway, back to the important subject! With the side profiles of the hatch I think I still prefer number 3 - number 2, whilst looking extremely aerodynamic (I believe you mentioned minimising drag) to me looks a little too much like an aircraft wing - I guess that’s a result of your pre-retirement profession! - whereas number 3, to me, looks a little more business like, possibly even a little aggressive perhaps?
Also, without wishing to go back too far in your previous posts, with the fin box is the carbon lamination on the inside of the box? A little later you made reference to glass lamination aswell which I would then assume to be around the ‘outside’ of the ply box.
One final question (honest!!) When you’re establishing the centreline of the hull, obviously the ‘chord’ of the hull to the waterline (ie hull draft) is relatively deep, so how do you avoid parallax error when ‘pushing’ the elastic cord into the bottom of the hull? (Hope that makes sense)
There was another question, but I’ve forgotten what it was for the time being…!!
Regards,
Row
Hi Row,
the central line is marked on the mounting board with the female shadows. By transparency this line is visible trough the hull glass laminate.
No parallax error since the elastic chord was just for visual verification from stern to bow and the already marked C/L on the hull bottom.
The box internal surface is black painted over the glass lamination. The red painted external box surface will be glass laminated.
OK for hatch 3 then ! For his use I shall , nevertheless, build a new deck wooden plug.
Actually I’m concentrating with interior set-up as learning laboratory.
Take care now, while wishing you all the best !
Cheers
Claudio
PS : Row I have taken a couples of pictures to show how I can mark the Center Line - C/L
Each shadow have the vertical C/L and on the mounting plane the first thing to do is to draw the Center line. The shadows are then aligned and C/L marked as such to be visible by transparency on the hull.
Of course, this cannot be done with a carbon fiber hull.
For marking centre line (C/L) on the inside of “carbon” hull is quite easy also.
Using the C/L of building board with frame cradles mounted on the board (as above) then position a laser light so that it aligns with building board C/L and then introduce the hull into frame cradles until hull is level.
Stick few strips of masking tape in the bottom of the hull, mark the laser light position line on the tape with pen, then scribe the C/L into the carbon, along the keel with straight edge ruler.
Cheers Alan
P.S You can pick up cheap laser-light from handy mans store.
IMO this is where using carbon has major construction advantage over fibre glass, you don’t need to use reinforcement with carbon to stiffen the hull…this is main reason I prefer to pay extra 40 Euro for carbon.
Cheers Alan
Hi Alan,
are you sure !
If the gain will be 40g, then I will consider it very expensive to pay 40€.
What I have to say is at the moment with 3 layers of 105g/m² the hull came out at 157g
Of course is not a classical hull in terms of height dimensions and this is why the deck is heavier then expected.
All together now the total weight of Hull + Deck + Fin Box + Rudder Trunk = 380g
The strength of the hull and deck are actually “over dimensioned” and next time I could use 3x80g/m² for the hull and 2x80g/m² for the deck.
It is also necessary to take into account that the double wood stripes on the hull and on the deck are well contributing to the total actual weight.
I shall note that there is also a small advantage with 3 layers since offering better hermetic performance then 1 layer of 165g/m² of carbon. More expensive if use 90g/m² carbon tissue (78€/m²).
Now, would be an interesting exercise to knows what is the measured weight of one of your AC120 hull and deck made out of carbon just to compare cost and strength.
Cheers
ClaudioD
Hi Claudio,
For sake of the exercise let’s put laminating skill aside as it is by no means the question and look at this way.
Using R&G price list, 160 gsm carbon twill cloth size 1m x 2m we pay €56 €, for same size roll in 80gsm twill fibreglass we pay 8 €.
For carbon hull we use half the cloth area for 1 x 160 gsm layer (cost €28) and using Fibre glass hull we use 3 x 80 gsm layers plus left over is used for hull reinforcements, using whole area (cost €8) and it takes 4 times as long to laminate.
Sorry, I was wrong as the total cost difference is only €20 and not €40. 
When it comes to weight 1 x 160 gsm vs 3 x 80 gsm plus reinforcement weight for same hull surface there is no question which will be lighter! (given same laminating skills are used on both) …but which would you say will be stiffer ?
I’m just saying in my opinion for less time work and a stiffer hull, the extra €20 is really worth it.
Cheers Alan
Dear Claudio,
About the Fin Box alignment. Do you move the fin or the hull while aiming for the perfect alignment? In other words, do you play with your two lead weights at the bottom of the fin to provide the proper moment resulting in a good alignment (fixed hull), or do you move the hull to align it to the natural positionning of the “gravity pulled” fin?
And am I guessing right that you apply and cure the expoxy simply by the equilibrium of the resulting adjustment setup? I don’t see any locking mechanism to hold everything in place after final micro adjustment.
N.B. I wish you good times ahead Row!
Alan the theory is with you, but at the end the result may be just the same.
In terms of stiffness I’m not sure that this parameter will be so different, at the contrary, I’m pretty sure that is the same and perhaps the 3x85g/m² may be a little stiffer, this is why I always recommend 3 layers of equivalent weight.
This do not exclude for the sake of strength to add another layer in the critical points.
I remember one of mine Class M Studio2, 130cm long, I used the carbon fiber of 93g/m² + Kevlar of 60g/m² to follows the trend and the bare hull weight was 147g and 8 years ago I payed 85€ + resin. Was just a free performance that did not brought any advantage against a 250g hull made with fiberglass and 10€
btw, with carbon tissue it is very encouraged to add Kevlar tissue to make the hull more resistant against shocks
Cheers
ClaudioD