| Re: Good start would be ...
[Re: Robi]
#87879 11/08/06 06:07 PM 11/08/06 06:07 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe |
Robi,
Lets use 0.5 mtr height as a start of point. Later it can always be raised or lowered if that is needed.
You can also measure your own daggerboards and get a rough estimation of good starting point for height.
I as a Taipan sailor want more height above the water, my current design can flap the wave now and then when I doublehand. I seem to remember my hull is 0.45 mtr high at the daggerboard well.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Good start would be ...
[Re: Robi]
#87880 11/08/06 06:19 PM 11/08/06 06:19 PM |
Joined: Oct 2005 Posts: 951 Brisbane, Queensland, Australi... ncik
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Posts: 951 Brisbane, Queensland, Australi... | Can we define the "freeboard" instead of the "height". I hate to get antsy but the height you are talking about should really be called depth, which is the technical term for the distance between the top of the hull and the bottom of the hull. This is generally speaking the draft of the boat plus the freeboard. Draft is heavily determined by the displacement of the boat, which F16's have generally fixed at about 260-270kg, and the rocker of the keel of the boat, so most F16's would be within a fairly narrow range of these values. Freeboard is what is required to keep the beams and deck above the water and hence waves, hence lower drag. So really, you need a draft, rocker and freeboard, rather than a height.
My hull design has got a freeboard of about 350-400mm (from memory) at the fwd beam. Where I sail is quite choppy so I need lots of freeboard for the beams to clear the waves. Haven't designed to a specific rocker or draft (so don't know those values off the top of my head), have just fiddled with it to make sure the under water hull looks good when supporting 260kg. | | | Re: Good start would be ...
[Re: ncik]
#87882 11/08/06 06:42 PM 11/08/06 06:42 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | Alright, Good points Ncik. Freeboard it is. This bring us to the requirement of having a section that provides definitions. Are you willing to make that for us Ncik ? To everybody : It is time to start using our wiki at : http://www.catsailor.com/forums/showthre...age=0#Post89232I will start on the article dealing with beam design. You guys take care of some of the other articles okay. Robi, you are our graphics men ! Our diagrams and pics must be good looking indeed. You are good at that. Rolf, are you up for some sail design c.q. building article. Erez, is the wiki well protecten and back-upped regulary now ? In short is it dependable ? Is the hosting secure and can the wiki be ported quickly and succesfully to another hosting (like our F16 webpage) in case of emergency. Even from the back-up files ? I've learning in my time as a network administrator that this was always extremely important. Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Good start would be ...
[Re: Wouter]
#87883 11/08/06 06:48 PM 11/08/06 06:48 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | For some reason I can't do Sh!t on our wiki !!!!
I have an account
Can somebody explain to me how to add, alter or start comments/articles ?
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Good start would be ...
[Re: Robi]
#87886 11/08/06 08:45 PM 11/08/06 08:45 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe |
The fall back angle of the bow is pretty much a direct result of the width of the deck. At the current steep angle the deck narrows very quickly towards the bow. I don't see the advantages of that. No reserved bouyancy at all and most waves will flow over the top splasing against the beam as the bow is not lifted much at all.
Anyway we should decide on the bouyancy distribution in the bow and then the corresponding fall back angle of the bow will simply appear.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Good start would be ...
[Re: Mark P]
#87887 11/08/06 08:49 PM 11/08/06 08:49 PM |
Joined: Jun 2001 Posts: 548 MERRITTISLAND, FL Matt M
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Posts: 548 MERRITTISLAND, FL | IF they were sailing a Cat with canted hulls etc they might have won and Qualified? Not to sound defensive, but the addition of canted hulls, foils or any other "gee-whiz" gadgets being discussed here would have in no way affected the outcome of these past races for us. You guys need to be having a few beers with this thread or maybe something more hallucinogenic. There is nothing revolutionary in what is being dicussed. As evidenced in the A class and F18s, it is the crew winning the events not the boats. Tigers are out-dated, yes, but still are capable of winning events, same with Marstrom A-cats. 1)Hull shapes are all trade-offs. The new trend in shape popularized with the Flyer is no faster than a well done older style design. They are easier to sail not necessarily faster. 2)Wing-masts, as pointed out earlier between the Taipans and Blades as compared to the Tear-drop Stealths, show no real performance advantage either. Theoretically, they provide better flow and more tune-ability in the rig, but they are much harder to tune correctly. 3) The Blade or Taipan would theoretically sail better with high aspect boards. With the low aspect boards they are put down when we leave the beach and never worried about again. For me, the less I have to do the more I can concentrate on the race..i.e. they're faster. 4) I have raced canted board and hulls and I don't know if they are any faster, but I do know that the boat is much more difficult to control on a start line. Mess up the start and they had better be faster by an order of magnitude to make a difference. I do not mean to knock any discussion meant in fun, as this would be a cool home project, but a lot of people spend more time fussing over fine adjustments to something that has no effect on what they are trying to achieve. Matt | | | Re: Good start would be ...
[Re: ncik]
#87889 11/08/06 11:04 PM 11/08/06 11:04 PM |
Joined: Sep 2005 Posts: 1,187 38.912, -95.37 _flatlander_
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Posts: 1,187 38.912, -95.37 | ncik, From anxiously awaiting on the sidelines Yes, please <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" /> As stated in one of your earlier posts Probably a better idea is to provide a set of resources that ppl can put into use in their own designs (general hull construction, tips and tricks, traps for beginners, photos, rig details, etc). Also, we could put our combined brain power to a list of improvements that can be made to current design/construction practices. This would make its way into the above mention resource of current best practices once it is proven on the water. A one up or two up, 5 to 20 knots, smooth and choppy water boat. A consensus boat. Matt M makes excellent points about all the gadgets. The cool thing about the class is all the possibilities and personalized gadgetry. Let's get some basic boats on the water.
Last edited by flatlander18; 11/08/06 11:36 PM.
John H16, H14
| | | Re: Good start would be ...
[Re: Matt M]
#87890 11/09/06 07:34 AM 11/09/06 07:34 AM |
Joined: Jan 2005 Posts: 6,049 Sebring, Florida. Timbo
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Posts: 6,049 Sebring, Florida. | I fully agree with what Matt said. But try to make the boat easier to sail correctly all the time, that is, make the control lines easily adjustable, that will lead to more speed.
There have only been some small advances in hull speed, mostly from reducing overall weight by reducing weight in the hulls, masts and sail material.
Then there is sail shape, like the square top mains, self tacking jibs (may not actually add sail power but are faster to tack, allowing the crew to get out on the wire a second sooner, wich makes the boat a tiney bit faster). But you need only look at the Tornado to see that rig improvments have gained more speed than hull shapes in the past 20 years. A "fast" upwind hull may be slow downwind, so that is the trade off you have to make.
I think the "Next Big Thing" in terms of actual speed improvements will be development of foils. Look at the Moth class. If they can do it on a skinny mono, we should be able to figure a way to make it work on a cat. All you really have to do is take two Moths, remove the side wings and connect them with a couple 8 foot carbon beams, move the mast to the middle of the forward beam and voila, you have a foiling cat!
Or...maybe we can talk Matt into mounting a couple of daggerboard trunks at an angle beneath the forward and read beams of a couple of Blade hulls, slide in some longer boards (steal some Inter 20 boards) and see what happens! <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />
I volunteer to be the Test Pilot. (or crash test dummy)
Last edited by Timbo; 11/09/06 07:43 AM.
Blade F16 #777
| | | Re: Good start would be ...
[Re: waynemarlow]
#87892 11/09/06 11:34 AM 11/09/06 11:34 AM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
Hull Flying, Snow Sliding....
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Posts: 3,528 Looking for a Job, I got credi... | Speaking to a few of the guys at Grafham... They need 8 kts to get foiling, but only 7 kts to stay foiling. I wonder if we;ll ever get pumping protests "to get on the foil" (or not).
F16 - GBR 553 - SOLD I also talk sport here | | | Re: Good start would be ...
[Re: Rolf_Nilsen]
#87894 11/09/06 12:33 PM 11/09/06 12:33 PM |
Joined: Jul 2005 Posts: 465 Oxford, UK pdwarren
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Posts: 465 Oxford, UK | Btw: I think I prefer to fall on my face/behind/knees on a relatively soft trampoline instead of crushing a solid and expensive panel <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />
Not to mention the solid trampoline... Paul | | | Re: Good start would be ...
[Re: waynemarlow]
#87895 11/09/06 06:10 PM 11/09/06 06:10 PM |
Joined: Oct 2005 Posts: 951 Brisbane, Queensland, Australi... ncik
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Posts: 951 Brisbane, Queensland, Australi... | Plus moths have no minimum weight so are extremely light, 9kg for the bare hull! I think they are about 25-30kg rigged, 90-100kg with crew...which makes them lighter than an F16 boat alone! With F16's on the water at about 270kg, we would need approximately 3 times the area of foil if it was in a T-foil arrangement, even more if it was a dihedral foil arrangement.
It can be done, but I won't have a part of it. If I wanna foil, I'll get a moth. | | | Re: Good start would be ...
[Re: ncik]
#87897 11/09/06 07:09 PM 11/09/06 07:09 PM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
Hull Flying, Snow Sliding....
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Posts: 3,528 Looking for a Job, I got credi... | Plus moths have no minimum weight so are extremely light, 9kg for the bare hull! I think they are about 25-30kg rigged, 90-100kg with crew...which makes them lighter than an F16 boat alone! With F16's on the water at about 270kg, we would need approximately 3 times the area of foil if it was in a T-foil arrangement, even more if it was a dihedral foil arrangement.
It can be done, but I won't have a part of it. If I wanna foil, I'll get a moth. The other thing with the foliers is they are a PITA to launch. Need to swim them out into enough water to get them sailing with foils down.
F16 - GBR 553 - SOLD I also talk sport here | | |
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