Well anyway, while you guys have been talking some of us have been sorting out a hull… I’ve been given a (posibly two infact) carbon hull, that falls in the LOA box, its a bit wider than i’d liked but it will do for sussing out the tecnical aspects and the rig, pics to come soon.
The plan is to fit it out, test it, then think about a more sutable hull shape.
Oh and dont all ‘how the hell can you make a cheap carbon boat!?’ the answer is you just raid a boat builders offcut box…
Stock sails mast, hull, deck, etc. - or maximum 36/600 sails - but no swing rigs, etc. Trying to keep the boats as close as possible to being the same.
Keel depth the same as stock
No “other” limits on keel, tilt mechanism, bulb weight, etc. Rememebr, this is where the “innovation” is supposed to take place !
This would provide a one design boat, with development ability in the area of the keel - except for length. Since there are no other variable, it will be hard to use the excuse of some “other” influence making the boat faster or slower.
Hmmmm - sounds great - with this kind of agreement, I might very well play. Someone needs to have a stock Hawk so we can see how much “faster” the modified keel really is.
I just talked to George Dornis. He has no objection to experiments to use the Blackhawk as a CK Trainer. He even agreed to produce a rig once the area was finally decided on( approx. 1.4 times the current 444= 621 total sail area).
He said that at this point he was not interested in producing the mechanics or doing canting keel modifications but that he would keep an open mind.
The bad news is that he said the bulb was 3.75 pounds.
So to be able to use the system Will designed we’d have to reduce ballast by some amount yet to be determined but not too much if the fin was kept the 10" in the kit.
UPDATE: that works out to a 2.8 pound bulb using the standard fin resulting (including the canting mechanism ) in a .4pound weight reduction which doesn’t seem like it should affect negatively.
I have a friend who has a stock B32 that he has not built yet. I’ll keep tabs on that. He would not be a candidate for the canting thing,as this is his first R/C boat.
I’d also like to add this: my interest in this project is not to prove or disprove Doug. I think that is the wrong way to go into this. It just sounds like fun…and that is why we do this, right?
Item#1: Blackhawk 32 - Yes
Item #2: No mods to kit in regards to rig, hull, or rudder - yes
Item #3: 3 channel radio only - yes
Item #4: Fixed forward foil - no, unless tests show required, K.I.S.S.
Item #5 ? OD Manufactures Keel strut, bulb, and <s>daggerboard</s> ? yes
Item #6 ? Individual design build Keel strut, bulb, and daggerboard (DB placement fixed and placed by majority if accepted) ? no!
Item #7 ? Kit supplied sails ? yes
Item #8 ? Alternate rig (TBD) ? no
#5 is no for time and cost issues (unless roy or someone comes up with a cheap quickly obtainable product). plus this is one area that is new to everyone and therefore, as dick stated, would be nice to see the many differing iterations of systems. agree that stock fin length/draft should be set in the rules
#8 is no once again for cost issues. it also means the kit is in “almost ready” form…create your cant mechanism and bulb, build it and go.
K.I.S.S. at its best, imho
cheers
BTW- will provide an updated spreadsheet with votes to date (as of 1/22/04 - 11 pm est), tonight around 11:30 pm est
I’ve never saied this boat so maybe Greg does have a point. A 36/600 has 850 actual square inches of sail however.Directly scaled that would be 671 sq.inches for this boat with a 16"fin.
One thing I am sure of is that if you keep the weight nearly the same and the sail area the same and add a canting keel with its requsite additional lateral resistance you will have a poor performing dog.
One way to see what might be expected is to test a larger rig on a stock boat. If a larger rig is used it would seem to be imperative to include someway to reduce sail by reefing or a storm rig or?
If this boat was designed as a canting keel boat from the start it would have more sail area and a significantly deeper fin with a greater drop in displacement; we can’t do that here because of limits on the mechanics.
doug-
thanks for the open minded approach to differing opinions. question…how big is the stock bulb of the B32? how much, in your professional opinion, could be shaved from it using the stock rig and sailplan? (I.E. - 5 lbs down to 2.5 lbs?)
Have any of you people thought about how strong the servo mechanism would have to be to move this keel when you are sailing. Don’t forget you have large loads to move when you consider the force on the keel it self, not to mention the weight on the bottom of the keel(lead bulb). Consider for a moment that you have about 3" of keel inside the boat to move a keel that is going to be about 12" to 16" long then you have the friction from the water on a boat that is moving, approx. you will be trying to push or pull maybe 100kg with a servo, very quickly so that you are able to have some type of decent racing. Then you must centre the keel prior to tacking, otherwise you won’t be able to tack and if you do manage to, you will probably break the keel off at the hull. due to the weight above centre of event theory.
Just a few things to consider, as I have said in another subject, canting boats need the loads spread thoughout the boat which means that a current mass produced one isn’t going to work for long before it folds up.
Eased sheets Peter
If you want a one design, you can’t have builder’s supply their own keels and canting mechanisms. If you want a semi-open class boat, its fine.
As to building the canting keel module, I thought from prior posts that this was an item Doug already had in stock. He has made numerous posts about a drop in module to convert regular boats to canting keel. I assumed he would supply that unit along with the bulb and fin.
If in fact a canting system has to be engineered from scratch the only way I know a professional would take on the job would be either for a fee (as Graham Bantock did for Doug’s F100) or for a guaranteed number of orders. I am not aware of anyone who would take this project on spec.
In all events, if the mechanism has to be engineered from scratch and supplied by the builder, I think you have hit a major bump in the road. There aren’t likely going to be too many people interested and skilled to do this development work from scratch particulary for an entry level boat.
Best suggestion (if there is no mechanism available) is that some of the canting keel advocates here buy the Blackhawk, come up with working reliable canting systems and then make plans and/or parts for the systems available. This is the heart of the boat, if it isn’t fully worked out the whole thing becomes kind of pointless.
Skiffy, the standard bulb weighs 3.75 pounds. Theoretically you can either reduce ballast by 40%(incl mech being accounted for) or increase sail area around 40%(actually less due to changes in the height of the CE).
The problem is that if you increase sail area then you increase pitchpole likelyhood downwind since going deaddownwind the canting keel has absolutely no effect. Especaily if you keep the fin the same length. You can’t increase the fin at the same weight because of limits on the mechanism.
If you reduce weight and keep the same sail area then you have a boat that won’t float on its designed waterline. If you compare 40 footers like the Schock 40 with other 40 footers you’ll see that the designers chose to reduce weight with approximately the same SA as other boats that length.
Best I can see we can’t increase sail area on the B32 due to the negative effect deaddownwind and we can’t reduce weight because the boat won’t float right. The choice-for the moment- seems to be to leave everything alone and add a canting keel(bad idea).
That brings up the fact that a canting keel requires extra lateral resistance when the keel cants. So if you leave it all alone and just add a canting keel and a fixed daggerboard you have a dog that has substantially more wettd surface than the original. Not to mention that you would have to move the keel fin to allow for a daggerboard. If you just stuck a daggerboard in front of the current fin you would wind up with terrible weather helm that gets worse as the keel cants…
doug- first off, no need to explain rig and foil balance to me…i understand the principals. please try to remember: this is a trainer (by definition - a boat that trains one in the use of canting keel technology). if she doesn’t float on her lines, so be it!. also, a canter won’t heel as much as a non canter, and this boat was designed for a fixed keel. in short, i believe that having her sit higher will have little negative effect and a potential for positive effect. the b32 wasn’t designed to “stand up” and sail, therefore with her floating higher, you will lose some LOA, but you will also decrease wetted surface and drag…so to get back on track, at 40% reduction in bulb weight (for the stock sailplan) we have a bulb thats 2.25 lbs. good starting point, thanks. still waiting on your vote and canting ideas (OD or individual)
roy- my opinion, as long as the bulbs and keel struts/foils are all equal, i don’t see a problem with a semi-OD/semi-open class boat. all other areas would be strictly regulated maintaining an even playing field. the innovations of sperate mechanisms would be like a teaching session (plus, i know you would love nothing more than to outdesign dougs cant system. wouldn’t you?) i hear your statement loud and clear as to fees for designing and fabricating (i am a commercial design-build specialty contractor and understand business operations fairly well). i also know (from being a lurker) that you are well connected with several people in the industry. what sort of costs, in your best estimation, would we be looking at for a OD cant mech. and foils? looking at qty/numbers of participants…it looks to me that 7 people are keen to this project. that means design, tooling, setup, and fab costs will be high if split 7 ways. with $90 for the hull/rig/sails/rudder, and guessing at $200 for a no thrills 3 channel radio and simple servos, you only have $200 to spend on the keel, its mechanism, and forward foil. cost overun (over $500) is likely under your system, i would believe. still waiting for your vote also.
question is, is cheap (“at-or-under” cost cap of $500) and semi-open design more important, or is pure OD? hopefully the vote will help decide.
Kind of the same reason I wanted to keep the keel to it’s factory length and profile, but allow bulb and canting options left to designer.
After all - we will need another three years to agree on Doug’s proposed idea of what constitutes an “acceptable” keel design. I was under the impression that the co-development of a trainer, would put (basically) the same boat on the water, but with different methods and canting keel ideas. I understand, Roy, that this means loss of one-design - but only in that area - and that is the area that no one seems able to come up with a production module.
If someone were to “give” you a complete boat, in theory, you could use your $500 to pay for a canting keel development. If we really can lower the bulb weight to under 3 lbs., there may be several ideas that get shut out of the process, because we have simply picked a one-design canting keel system that still isn’t available. Is it wrong to offer an open “design” book to people - bring forth their ideas and race all together? Maybe Doug’s concepts will win out - but maybe someone will have a break-through idea that reduces costs, works, and all can use.
I just have a fundamental problem in blindly accepting a one-design canting keel measurement specification, for something that has yet to be built and demonstrated on the water. This “exercise” could not only provide a way for cost-effective canting keel evaluations, but if the design of the system is left open, those who don’t want to “bet” on Doug’s ideas could develop and use their own - meanwhile the non-inventor/developer could ask/purchase one of Doug’s yet to be produced systems and install it in the boat.
Since r/c canting keels have yet to be built and demonstrated, I don’t think a hasty selection of only one design should be contemplated - at least not until any options are explored as well.
Just my view of course - and in no way should this be interpreted as a “personal attack” - simply a fact that what you want to select as a one-design component has yet to be demonstrated. Heck - maybe a group could get Grant to allow a purchase the keel mechanism from Wind Warrior - at least that seems to have been demostrated on the water.
one design when sorted
3)Y
4)? needs more work
5)Y
6 N
7)? needs more work
8)? needs more work
Voting is an interesting exercise but I’m not convinced a boat can be developed by voting on highy technical issues that few of the voters understand. Helping to get everybody to understand the issues might be more important immediately in addition to more research.
My thoughts-
A)I think this can be done but things will have to be looked at carefully; I’m not going to jump on board something that is not carefuly thought out and that won’t perform as a canting keel boat should.
B) Everybody has made valuable contributions and I hope will continue to do so.
C) the F100CBTF mechanism is too expensive to consider for a trainer; one hope is the excellent design Will has done but it needs to be tested. The F100 canting keel installation module(pivot and watertite seal) is excellent but also too expensive for this application. Matt and I will be testing a much less expensive solution.
Wills idea there has merit as well.
D) I’m 100% convinced that the final CK Trainer should be a strict one design BUT in the interim people should go forward with ideas that they think have merit–trying to stay within or close to the Targets listed in the first post. When someone does a prototype that the group thinks looks promising we should all contribute to ship it to those interested in evaluating it for a set period of say two or three weeks; then ship it to the next person. At this size and weight it won’t be too expensive if everyone helps.
E) great things are rarely easy; it takes guts, perserverence and lots of work to put a first rate boat together. Doing the job the right way should be paramount-not the quick easy or too cheap way necesarily.
Doug Lord
–High Technology Sailing/Racing