Just had a most interesting conversation with Brett McCormack.
Neil tells us that Moonshadow will be the death of us because of the expense of construction. He cites the need for an autoclave to hot cure the ‘special’ epoxide resin.
Brett tells me that the ‘autoclave’ consisted of a cardboard box containing some 100W light bulbs and a thermostat from some piece of redundant household equipment found lying around under the bench/stairs.
I think that this rather puts the whole thing in perspective.
I don’t believe I mentioned an autoclave, that is your inference Angus.
My post-cure oven is a household ceramic heater/fan in a sheetrock box that will fit my M Class boat molds. It has a thermometer that is adapted to monitor the internal temperature. Post cure resins have an A and a B stage with specific temperatures to be held for specific amounts of time. I ramp up or down manually because I really haven’t had the energy to add a remote thermostat yet. One of the truths about a hobby is that once something is cobbled together, and it works, the commitment to make improvements is an uphill hike. Its is more the end product I am interested in.
Never the less, post-curing in a cardboard box with light bulbs takes the casual approach to epoxy work to an extreme. It also sounds like a fire hazard. Does his wife know what he is up to?
Let me share their one my thing, that for very long time “running in my head”, but saw this big discussion, I has decided it here to introduce (I know - almost in English…).
In many major sports (glaiding) and in a number of model classes (fast boats - FSR) are exist sub-classes: “Standard” and “Open”.
You may want to consider placing them in the FOOTY?
The first limitation could be to help distribute these boats among children and novice modellers. Here the model of other “standard” sub-classes may even prohibit the use of laminated glass, carbon, and any “space technology” & high cost. It this group should be recognized by the proposed models available on the IFCA website.
The second sub-class could be realy “free” - just only IFCA one “holy rule” - measures box. Big space for sport, more invention, new technologies, maybe more money, etc.
I (and I think also maybe Flavio and many others) would be interesting to play in the semi-scales group of FOOTY (multiple ours opponents considered: “The most FOOTY’s boats for regatta is abnormal in their shapes”).
Regardless of the sub-classes in local competitions would start all boats (as in the WRC race cars), only the results would be made available for all (generally) and additionally for sub-classes. I think that there would be a big problem for the organizers (and I think this also about yourself and maybe FT EU GP 2010).
The “Clear the rim of the box” aspect of the box rule is surely not a major difficulty. After all, there is no nescessity for the keel to rest on the bottom of the box—the deck and any hull protruberances need only be below the rim of the box. The difficulty would arise only for hulls placed diagonally , or tipped up at bow or stern. It would not require much “inspection” at pond side to see if all of a competitors rigs matched the clearances of the “measured and tested” example. This way, no limitatations need to be placed upon the number and size of rigs at all.
This would then allow for only a single “Box Rule”.
Given that you are looking at a wildly advertised event, what’s missing?
Answer - the crowds. I am 57. Mainline steam power became extinct in UK when I was 16. For any years after that, the appearance of a powerful steam locomotive hauling a mainline train would attract hoards of enthusiasts of all ages anywhere it went. Now it is frankly boring.
Another point. Come off it Neil. You know as well as I do that model yachts have been pushing for the highest ballast ratios they can get since the beginning of time. Building a really good bread and butter hull is both expensive (oly the very best timber can be used) and tremendously highly skilled. What we wrinklies are doing is mystifying plastics because we do not really feel at home with them.
Incdidentally, question to the deasd vegetable entgusiasts. On smell! Do you really enjoy the smell of formic acid?
In many major sports (gliding) and in a number of model classes (fast boats - FSR) exist sub-classes: “Standard” and “Open”.
You may want to consider placing them in the FOOTY?
The answer is NO
This has been proposed before and dismissed as detrimental (BAD) for the class.
I realise that Pawel is a new member of this forum and has not been involved in earlier discussions which have thrashed this to death previously.
I think that what is bothering some people (me), is the incredibly low hull weights that some (more professional) builders achieve. I made my Glass Petrels I & II by carving a block of pink polystyrene house insulation foam and then covering it with polyethylene film. I then added two layers of extremely light fibreglass random mat and epoxy resin, applied as thinly as I could. I bagged the whole thing in a heavier polythene bag and sucked out the air using my Shopvac, smoothing down the surface with fingertips to get the epoxy as thin as possible before it set. The foam plug was then removed.
Nevertheless, the completed hull alone weighed more than 150 gms and the whole boat with rig, keel, radio, 4 AAA batteries and all comes in at 418 gms.
Compared with 25 gm hulls, I am obviously ‘nowhere’.
For me, any hobby involves doing it myself. Buying my hobbies is not my preference, and I had hoped that the Footy class, as opposed to the other larger classes, would suit my needs.
It does seem that a hull purchased from a commercial builder will in the future be the minimum requirement for any sort of competitive performance.
You are the type of techinically educated DIY guy whom the Footy class should suit down to the ground.
Look at Brett’s build log of Moonshadow (in the Moonshadow thread, I think). That doesn’t give away the whole ranch, but it gives a very good starting point. Gary Sanderson - who started from a completely clean slate, apart from having general engineering training and being good with his hands - is these days obtaining results that are not far away from Brett’s, or may even be superior. :devil3:
The result’s of Andrew Halstead’s work (thread A Blatant Plug) are marginally heavier - by perhaps 10 grams at the very most. As a proportion of hull weight, this is high. As a proportion of the overall parasitic weight of the boat it is trivial.
Both of these people are good craftsmen, not geniuses. They work in garages, on the kitchen table, whatever. Facilities are home handyman tools.
In any technically driven sport, making the best hardware helps. Experience goes a long way. But there is no reason why you should not build up ‘best of second rate’ knowledge very quickly.
Before anyone asks why I had Moonshadow built in New Zealand if it was so easy to do it myself - I have serious arthritis in my hands and find it difficult to pick up a pen. OK?
To Angus
My current thinking about an ultralight hull made by methods accessible to the non-professional are shown here. I think the method has possibilities even though the first execution was poor. I will persevere—.
The ‘designer’s method’ refered to by Brett somewhere in these threads was a Depron sandwich.
Depron is the type of highish density closed cell polystyrene used for things like McDonalds burgrer trays. It is also used for underfloor insulation. It s not very easy to come by in sheet form in Europe (it is Dutch by origin) and difficult to find in North America.
Akela was built from a Depron core and very substantial (and unnecessary) carbon reinforcement. Misunderstandings between me and the builder resulted in a hull that was as overweight as yors rod. However, sbsequent experimen suggests that a hull should be quite easy to make down to about 15 g. Quite frankly, the difference between 10 nd 15 g is insignificant, so long as proper weight disciplne is obsrved. In a rcent post the anount of resin just left around the rudder tube was no much less than th total needed to build Moonshadow
FWIW - same process I used for my 1 Meter trimaran and my RG65M (multihull).
You can leave foam in; you can remove by melting with acetone or lacquer thinner; or you can cover the foam with plastic packaging tape and lay glass up over the tape. Tape acts like a release agent, and a thin popscile stick or light pressure from an air compressor will usually "pop’ it loose from the plug. Watch out for designed that get wide - then get narrow as very difficult to spread the glass too far to get off plug.
rod, Your photos reminded me of my ec-12 rudder i was working on. had it shaped and ready to glass. I then laid up the glass and resin. in 2 minutes I had a shriveled mess…Aint building fun…
Just to clarify: The foam was the basic male mould, which was covered in very light fibreglass random mat and then coated with Varathane, an outdoor urethane ‘varnish’. After the whole thing had set hard, I cut out most of the foam with a Dremel tool, intending to leave a 1/4 inch layer of foam under the ‘skin’. I then got the ‘bright’ idea of removing all of the foam with methanol, which ‘sort of’ worked, except I got interrupted and had to leave the job uncompleted, as I had not completely removed all of the foam in the forward part of the vessel. The remnants of the half-dissolved foam then distorted the glass-urethane shell in my absence. One of the lessons that might be learned from this is–“never marry”-- your wife will inevitably call you away to run an errand.
Sorry, Angus, for continuing the ‘thread creep’. You’re right, we need a new thread for odd contruction methods.
