A little more progress to report - positions of deck hatches for access to various components has been established. From aft, the first hatch will be over the rudder tube and servo; next will be a large opening to enable service / adjustment of the winches & battery; a third hatch will be in the foredeck to allow limited access to the closed loop sheet turning blocks.
As we experienced an incredibly rare period of good weather last weekend (and my son had invited some friends round for a ‘paddling pool’ party) I decided to carry out another float test to check how she was sitting to her waterline. The hull was fully ballasted (3950g, designed ballast 3900g) and an additional piece of lead (offcut from aft ballast section) weighing 475g was added below the mastfoot position. This gave a current ‘all-up’ displacement of 5659g (designed displacement of 6167g) made up from:
As can be seen from some of the pictures, she’s still floating higher than the designed waterline which at the moment I’m pleased about because the additional 475g wasn’t scientifically calculated, it just happened to be lying around! Looking at my current displacement figures (5184g without extra ‘ballast’) I’m quite hopeful of the finished yacht being fairly close to Claudio’s designed numbers.
Anyway, the pictures. If I recall correctly the difference between designed w/l (marked on hull) & current loaded w/l was approximately 4 - 5mm. I’m sure if I sat down & worked from the waterplane area it would be possible to calculate the additional mass required to bring her to designed w/l!!
Edit: Just a thought (and a rather sensible one as the weather is nice again!!) I think I may install all the components that I currently have and carry out another float test - any excuse to cool off in my 4 1/2 year old’s paddling pool while he’s at school!!
Hi Row,
nice to see pictures from the water !
In the weight sum, it seem that deck, hatches, electronics and rig are not yet included or I miss something ?
Cheers
ClaudioD
You are correct in your assumption, the only additional weight was the extra 475g placed in the mastfoot area, which I’m fairly sure is nothing like enough to allow for the 3 sail winches (Hitec HS785 @ 110g each), rudder servo, batteries, deck and of course the rig. When I list it all like that it seems to be rather a lot more to add!!
From my last post, I’ve nearly finished installing all the extras that I already have and will post some more photo’s & information regarding weights and waterlines etc.
Seeing ‘Enterprise’ in the water certainly motivates me into making further progress - I’d quite like to do a fully planked deck with the various doghouses and hatches, however, maybe for the time being I should just concentrate on getting her sailing and leave the detailing for a winter project!
In the meantime, I’ll just go & fit the rudder servo and then she’s ready for another float test - should have it done in the next 1/2 hour or so…
Right, here we go for take 2 (or is it 3) on the float test!!
As mentioned earlier today, I’ve fitted the 3 sail winches including the various blocks & closed loop bits, the rudder servo has been installed also and the deck carlins for the hatches are also dry fitted.
Each sail winch (Hitec HS785) with its closed loop components weighs 120g, giving a total of 360g. The rudder servo (Savox digital low profile, 9Kg/cm torque @ 6volts) weighs approximately 50g with its rudder shaft coupling. I’ve also placed the additional 475g weight to allow for the rig and deck (does this seem a reasonable estimation?). ‘Enterprise’ initially floated slightly stern down which was to be expected - the sail winches needed to be mounted further aft than I initially wanted to give sufficient travel if I decide to use a genoa in light winds. Also, the rudder servo, being mounted directly above the rudder shaft acts as an additional lever (distance from CB). All this resulted in the additional 475g weight needing to be moved further forward so that she would still float on her w/l.
So, the pictures - any further questions then please don’t hesitate in asking.
Hi Row,
I really enjoy.
The 475g could well replace the rig and other stuff.
In case you need for more equilibrium, then 150-200g put at the bow will probably cure the problem if needed, although a low stern will be compensating during sail propulsion.
Not to forget that the water plan is of 1351cm² therefore 1mm sinking will be equivalent to 135g
Cheers
Many thanks for the information, especially the water plan area - I’d forgotten that it (and the deck plan area) were quoted on the 1st post of your own build log…
At the moment I’ve got some 1.5mm ply which has been cut out with a 3-4mm overhang along the deck edge. It weighs about 240g so by the time it’s had a layer of glass (say 50g/m2) on the top & a coat of epoxy on the underside the total weight is going to be approximately 275g. As a method of reducing this I’m now considering some 1mm ply - any thoughts on this?
Obviously, this doesn’t include the rig & sails (rather important!!), the battery & receiver (also rather important!), the rudder (!!) or any paint. So, against a designed displacement of 6167g I’m left with 203g to cover that lot!! It’s certainly worth remembering that if I’d kept to the ‘standard’ rc yacht rig none of this would be an issue & I’d almost certainly be carrying additional ballast to meet the designed displacement.
So, how can ‘Enterprise’ go on a diet? The most obvious starting point is to reduce the ballast to the designed weight of 3900g saving 50g. Additionally, the winch mounting board could easily be reduced in size, probably saving another 50g. If I were to use 1mm or even 0.8mm ply for the deck that could potentially yield a further 80g-110g (calculated pro-rata from the 1.5mm ply). Those ‘savings’ gain me an additional 200g, thus now giving me approximately 400g for the rig, sails, paint, battery etc. Still almost certainly not enough…
So, do I also ‘cheat’ a little and consider raising the waterline? If my memory serves me well, I do recall that being mentioned in another thread (I think Earl was talking about improving heavy air performance with his ‘Yankee’). Decisions, decisions…
Any thoughts??
The situation is still rather confortable, no panic !
Let’s forget about wood deck for the moment.
Deck surface 21.85dm²
Assume, for example, 2 layers of 50g/m² fiberglass you get : 0.5g/dm² + 0.5g/dm² x 2 = 2g/dm² x 21.85 = 43.70g + 7/10g bonding = total deck weight 53.70g therefore much less then 275g or 183g if 1.0mm plywood used. The multiplier of 2 is due to epoxy content that generally is 50% of total composite weight.
Lamination to be made over a glass panel ( please don’t use your windows !..if you want keep your peace !)
At this point, to increase your psicological confidence in terms of strenght you may decide to to increase the glass weight to 80g/m² glass .
Remember the deck function is a sort of umbrella to protect the electronics.
In the worst case you may reach 3.2g/dm² equivalent to 69.9g + 10g bonding for a new total of ~80g for the finisched deck which is still 100g less then 183g with 1mm ply. With 2 layers of 100g/m² glass you will end up with 97.5g bonded deck.
Up to you !
So wait to get all weights elaborated and measured before deciding for the deck configuration or to reduce the Ballast. BTW, one way to reduce Ballast weight is to use a drilling tool at low revolution and some water as lubricant…
Of course the last resource could profit of 1mm sinking (135g) that is nothing against performances and while keeping intact the ballast righting moment as designed.
I’m confident that you will manage it right.
Many thanks for the information, I hadn’t considered a glass/epoxy deck - from a weight point of view it makes perfect sense. At the moment my only way of producing a single sheet of sufficient size would indeed be by utilising one of the windows at home. So, is it better before or after the window cleaner has been… !!
Seriously though, I’ll look into acquiring a piece of glass with sufficient dimensions. Mind you, as a potential alternative, one of my work benches has a kitchen counter top (50mm chipboard with a mildly textured melamine facing) which may work if covered with parcel tape - it may be worth experimenting with - we’re going away for a few days so I’ll give it some thought and possibly try a small scale sample when we’re back.
Aplogies for the delay in responding to your last post, I’ve been having an ‘interesting time’ over the last 5 - 7 days which hasn’t allowed any progress or reading up forum postings or notes, I’ll try and find the time to PM you hopefully before we go if not when I return on Monday 2nd June.
Regards,
Row.
By the way, how’s your new flat coming along, aren’t you supposed to be moving in soon? + I do hope that with all the re-modelling going on a suitably sized space will be found to accommodate your workshop. Maybe if my ‘Enterprise’ gets wet this year yours will come out of storage to enable a continuation of your excellent build log. I am of course utterly convinced that the reason for my slow progress has been down to virtually no model boat building experience on my part and of course not having another build log to pinch, no, sorry, borrow relevant ideas from!! So far I’ve drawn inspiration from the various EC12 build logs, Canterbury J logs and generally re-reading quite a bit of yours, Alan’s, and unnamed logs of other build logs past & present. Then of course there is the perrenial problem of that annoying little thing called time…!!
Hi Row,
as support for deck lamination you could also use a plastic sheet 1mm thick generally called anti-glare, non-glare or diffused glass for painting framing.
Epoxy do not adhere.
The Flat is not ready yet, it may take another month before removal. For modelling I’m thinking to use a corner in the underground garage but still far from doing some work.
As mentioned in a PM message, I publish here below the pictures and technique I used to build the 15mt Int. Class Tuiga Deck. (not yet finished).
Base support material plywood of 0.6mm, stripe 5x1 lime wood stripes, 0.3mm black carton stripes, cyanolite glue. It is a slow process work.
Of course the weight margin available on Tuiga allowed this working method !
Cheers
ClaudioD
There is also another possibility and much lighter.
Surf board use that tecnique with images printed on rice paper.
Print on paper the deck layout in colour at scale 1:1 with wood stripes and black separation lines.
Separated A4 sheet are needed to cover the full lenght.
Assembling the printed sheets and put them in between two glass layers of 50g/m².
Colour may fade out a bit, therefore would be better to reinforce and darkening the print. Wood teak or light brown coloured paper sheets are also OK - only black stripes will be printed.
The central King Plank and the sheer line bords could also be printed in mahogany colour.
typical Dragon Deck, this is new mine was 40 years old.
So, first the glass layer impregnated with epoxy, then the paper sheets also lightly impregnated with epoxy and finally the second glass layer. Roller to squeeze and remove the excess of resin
Of course, as usual, tests samples are.
Ok, so still no decision on deck material & very little workshop time…
This certainly doesn’t warrant a picture but the sail winch ‘platform’ is now bonded into place and I’m now working out how to do the chain plates - hopefully an update soon with pictures.