Moonshadow, I noticed has a 2x2 arrangement which must raise the CG/Rollcentre of the hull considerably.
Logic suggests that as low as possible - while still in the hull - would be optimum.
I have rolled a pair of styrene tubes to take nimh or alkaline cells and these will be velcroed where the fin joins the hull. Can’t get any lower and I’m not planning to do a Dr Chris with the cells. (Another story another time)
Couple of pics attached - as always the first attempt is larger and cruder than the mark 2
There are a number of excuss for Moonshadow’s battery arrangements.The mosdt honest one is lack of time on Bett’s part to make anything more sophisticated and my being too lazy to do anything about it afterwards.
The ones for press, bar etc. consumption (and they do have a grain of truth) is that the batteries are structural- they support the servo tray if any work is being done on the servos, etc. This could equaly well be done by a block of foam inserted for the occasion.
The other slightly nastier problem is the combination of narrow beam and a keel box (for the removable fin) immediately ahead of the batteries. There isn’t a lot of room to play with.
However, I’m with you all the way - just dropping behind as usyal.
No adverse comment intended - and indeed the free space inside Moonshadow is minimal.
If it of interest to anyone ordinary styrene Polystyrene as well as EPS and depron can be softened and moulded in hot (boiling) water - so the tube rolling involved a 15mm copper pipe - exactly the right diameter for AAs - two rubber bands and a deep jug
I am completing a Footy with a large hollow keel into which the batteries may be slid. The hull is carved (with a Hunting Knife) from pink foam insulation, then sanded and glassed. The keel has a wooden box, to contain the batteries, with the sail servo mounted in its top. I don’t know if this is legal, but the batteries may be inserted and removed while the hull is floating.
I attach here some photos, but the proof is in the…!
The hull is glassed enough to prevent crushing during handling. The electronics are merely embedded in holes cut in the foam.
I was actually thinking about doing something like that, except with the batteries horizontal in a full-keel 12meter style hull. I still have the skeleton sitting on a shelf though, haven’t done anything with it since I framed it out.
If the keel is deemed to be part of the boats hull - a copper tube encasing the batteries as a keel bulb could also be used. Just run wires up the center of the keel in a small diameter carbon tube to get to the radio gear.
:scared: Oh oh - I’d better check out now. I think I hear the members of the technical committee on their way in.
Here are three pics of the almost completed Footy. (I’m thinking of calling it “Da’s Boot”.) Ugly, ain’t it?
I would be very interested in some consideration of this design by the technical and rules committees. I would also appreciate any discussion of the idea that ‘form drag’ is of little concern at these small sizes. My hydrodynamics understanding doesn’t extend that far.
At these small sizes, I believe that form drag is the overwhelming drag component, and the drag coefficient is quite large. Check out my thread on hull testing.
With regard to batteries in the keel, you ought to check with the rules guys. It is most likely illegal (otherwise we would all be doing it).
with regards to the width of the keel, from a fluid dynamics standpoint, I don’t think your boat will point very well to windward. sailboats rely on the lift generated from the keel, to combat the lift generated by the sails. The keel might be so wide that it creates a “stall”, and will likely result in the boat turning off of the wind.
I’m presently charging batteries and will try sailing tomorrow (Saturday) at my local testing pond. I just hope the snow holds off for the next couple of days, as I hope to race it on Sunday at Windsor, Ont.
Hope springs eternal!
Actually, the class notation is such that: “anything not specifically prohibited or restricted by the class rules is legal”
The definition of appendage from within the rules only speaks to the “Rudder” as an apendage. It does restrict “retractable or moving hull appendages”, but nowhere within the rules is the keel addressed - other than to show it in the measurement box graphic. :graduate:
Thus, it is my opinion based on the rules as written, that perhaps you all “Should” be doing it since it isn’t specifically prohibited. When “playing” in the arena of class rules, read what is written - not what you think was intended - especially in an Open/Developmental class !
If that is a real reading of the rules, then that could change a lot of footy tech for a long time to come…
Unfortunately for that argument, it also says in the rules that
“C.2 Batteries are restricted to 4 no. AA size batteries placed within the hull.”
i don’t think it is very hard to come to the conclusion that a keel that is seperately built from the hull, and attached, is no longer part of the hull structure. it is a fitting or appendage. if the keel were to be part of the hull, (as in the case of a 12 meter style boat, where the hull simply narrows and changes shape to make a fin) then i could see how that would be arguable that one could place the batteries in the bottom of the boat, and still be within the rules. however, i cannot see how, if the keel must be seperately attached, than it could be considered to be the same part as the hull. the english language defies that working.
i dunno,
just my .02 take with as much salt as necessary to dull all and any unintended insult!!!
This subject was discussed offline (at lunch) by several of our local sailors, last winter. The basic subject was putting the batteries in the bulb. This would obviously cut the overall weight in half. We discussed methods of doing it, and it looked very promising. Then we checked the rules. Everyone agreed that the requirement to put the batteries in the hull did not allow putting them in the bulb. The issue of putting them in a very fat keel fin is a little more ambiguous, especially if it can be accessed from inside the hull. It is also less advantageous. However, I recall seeing something on this forum regarding that very subject, a few months ago, by one of the class rules mavens. The details have been forgotten.
Practicality
The fat keel will probably work very well if it has a long enough chord, probably at least 7", with a nice airfoil shape. It may add 25% to 50% to the overall drag, which will eliminate much of the advantage in weight savings. But you should try it, and see what happens. You will have the enjoyment of exploring a new frontier. That is what the deveolpment class is all about.
420sailor: I would be inclined to agree with you so my first look was for the “keel” to be included/described as an “appendage” - which it isn’t. Thus if it isn’t included in the rules as an appendage, it must be part of the hull (whereas the rudder is specifically identified as an appendage) and is in fact exempted from the portion of the rule which prohibits appendages from moving or being retractable! As I previously noted - can’ only go by what it says - not by what is was “supposed to mean”!
I was thinking of the Footy that is being laid up in a left and right half hull with a vertical seam. Since half the hull and half the keel, and half of the bulb are being laid up as one piece, the method of construction should not control the application or use of batteries as low as possible.
Can’t remember whose boat it is right now, but I do recall having the thought pop up as I was looking at photos of it prior to assembly. By allowing inside a hollow 12 meter (or Soling/Fairwind) style of keel, but not in a blade/bulb type also invokes the thought of class rules control by hull design - which is what the original concept of the class wanted to stay away from. (I think ?)
In reality, I have problems with the rule about batteries - as the original argument for their size and cost has long been passed by with ultralight construction using expensive materials like carbon fiber and micro-servos.
A development class rule always starts with the best of intentions and soon the class finds itself strapped down and forcing everyone to make a similar style of boat - instead of allowing innovation and development of ideas. “Cookie Cutter” design springs to mind here too.
I guess I will need to consider the design I have been playing with and simply build over the winter. Whether it fits all of the rules minutia is immaterial - but it will be developmental. Part two is to see how competitive it really will be. Part three will be listening to all the reasons “why” it is illegal. As more rules were added to the original Footy development concept, the less interesting it became to me.
I still wonder what the rules folks were afraid of as they adopted additional rules beyond the box concept. It “seems” we went from “Hey, let’s see your ideas” - to one of “Oh my - way too radical/expensive/complicated for the home/Boy Scout builders.”
Could everyone (both sides) PLEASE stop playing the cost card! The average British child aged 6-12 gets about $ 13.60 a week in pocket money or $19.75 aged 13-16. This is pure gift - money for chores, from birthdays, etc. is in addition. It seems to me that if I am 13 and seriously want to build a Footy, the cost of the materials is not going to get in my way.
NB the ‘no profit’ cost of a set of BUG plans from the MYA is £3.50 ($ 7.15). Roger Stollery reckons that the price of a Corex boat electronics is about £5.00 ($10.14). This uses quite a lot of carbon (spars, etc.). Roger is making nothing from the design and the MYA is making damn all.
Registration of a Footy is free in the UK, but AMYA registration in the USA is $ 7.00. So if we build a Bug in the USA and register it with the AMYA, our total bill excluding electrics is about $24.29 of which $10 or a mere 40% is actual hardware. The rest has gone into the collective maws of your and my national authorities.
I believe it would be at this point in the discussion I would furrow both eyebrows, look over the top of my glasses and suggest the same child in your example of 13-16 years old “receiving” about $19.75 - but who has aspirations of having both a winning design, as well as a good looking boat like the one he sees at the pond that is all sleek and sexy in it’s carbon-fiber glossy splendor would have to save just over 21 weeks in order to purchase one of Nigel’s beauties ready built (at a touch over $400) - PLUS cost of electronics.
I’m not sure about the UK - but over here, most carbon dealers usually aren’t happy (or willing) to sell carbon fabric in lengths less than a 1 yard (just under 1 meter) cutting so an entry level material cost just to get started would be about $35 for cloth, and about $50 for WEST epoxy in a quart/pint (resin/hardener) size.
Then there is the matter of building first a plug, then a mold in order to layup a hull. Then the cost of electronics at perhaps $60 or so. Assume mom doesn’t have rip-stop cloth for a sail so there goes about $5 for a yard of that stuff (minimum 1 yard size purchase). I would hope the child could find a small carbon tube for mast/boom/bumpkin and have an adult purchase some lead shot from the local gun store for keel weight. THEN we must assume he has the skill/knowledge and building abilities similar to those that Nigel impresses us with when he rolls out one of his beautiful hulls.
When all done - materials to equal a carbon build like Nigel’s will run about $150 - with a concession from me that he has plenty of materials left for probably a dozen more boats - albeit the radio gear purchases may be needed to eliminate pulling radio boards to transfer to other hulls.
This certainly isn’t a child’s type of a build. Unless there is a separate set of rules to break out the home-built boats from the production boats, my guess if beaten, the child may not return for a second time. Then again, with the weekly earning of some children (like my grandchildren) they could probably afford a pre-built boat in just four weeks of saving. Helmet, moto-cross boots and a 125 cc motocross motorcycle is the manner my 11 year old grandson saw fit to spend his money. He attended the ODOM nationals with me when they were in town a few years ago, and equated slow, quiet sailboats to older, gray haired and mostly overweight gentlemen - of which I am one - well I’m balding instead of turning gray! For him the speed, noise and excitement comes from his motorcycle. I guess he got that from me in my younger days when I too was a “motor head”.
Regardless, until I see photos of a pond bank crowded with youngsters (well under the age of 55) I don’t believe for a moment many will be drawn in or build to the level they would have to compete against in an open, national event.
Total weight = 385 gms, including 45 gms of supplementary and easily detachable “Aquabond” bulb on base of keel.
As to cost:—
Foam removed from house when new windows installed.
West System epoxy resin borrowed from friend.
Fibreglass was gift from constructors of rowing shells
Aquabond solder cost $15.00 Canadian for 500 gms
Sails were from a shopping bag.
Plywood left over from constructing a Hagerup Razor
Mast was $15.00 for carbon tube. Used only half.
Booms from shiskabob skewers
Radio was less than $100.00 Canadian, and used for 4 Footys.
Just how did carbon cloth get into this? I do not want to take up cudgels with Nigel, for whom I have the greatest admiration, but his Lajabless hulls are not particularly light, although they are immensely strong. The 10 g. hull of Moonshadow uses minimal carbon (in the form of carbon tows, which ARE available for a few cents at a time). I hope that Brett will not mind my making it public, but the deal for him to build Moonshadow for me was that I pay the cost of materials plius shipping. The shipping part is a saga in itself, but the materials was NZ $ 20 f(US $ 15.33)for a complete boat with 2 rigs and servos (no Rx). Decals extra.
It has yet to be proven whether MoonShadow is the best thing since sliced bread, but one thing is certain: if she isn’t, its because my design is wrong, not because you have to throw more money at the problem.
Of course Brett’s setup costs are low. What lives under his bench is the treasure trove of many years of imagintive Footy building.
And of course kids don’t just get paid in cash. Doting grandparents, wicked uncles, etc., have been known to buy hem a metre of ulra-light glass cloth. Incidentally, SP sysyems (or whatever they now call themseves) epoxy resin comes in considerably smaller packs and is cheaper anyway. I can pay $20 +/- for a 250 g. pack - that’s expensive, but penny packets always are.
And as I noted - at the other end of the spectrum is Nigels “artwork” at over $400
So what is the point? Just responding to your post in which you stated " Now tell me about expensive materials." - which I did.
Ahhhh well 11:07 PM and time for bed for me. Just restored all my bookmarks after an unplanned computer crash during which time I was sweating that I wouldn’t be able to find them. I did, I restored, and now I am off to bed to dream of Footy’s racing F-48’s and all the while cursing the ISAF for dumping the Tornado class from the Olympics after China. No good dirty rotten B-tards !
'night Angus - we can take it all up again tomorrow. Ha Ha :zbeer:
i push the sail of my “glass” Lajablesses, for their quality and relative cheapness ($110, with shipping).
the carbon versions are priced on the high-end, to somewhat discourage sales of it, and to keep interest in all other material versions,
if someone wants to get a full carbon beauty, then i welcome them to do so.
It’s just a lah dee dah version for for the “carbon-fiber-must-have-type”.
I’d just be able to purchase more inventory:lol:
as for keel being part of the hull, the new ones are, but good luck putting batteries inside that keel section.
and weight, total Lajabless displacements are from 350gm, to a layden one at 380-400max.
my latest so far (semi-rigged pic)is at 100gm so far. light, and superstrong…
could be even lighter with the use of a mc-rig, but i prefer burmuda-one.
(burmuda shorts too!:lol:)
