| Mast weight and rightability #139700 04/12/08 10:45 AM 04/12/08 10:45 AM |
Joined: Nov 2006 Posts: 120 Finland valtteri OP
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Posts: 120 Finland | Hi all,
I would like to ask you if you could tell me your mast weight and if you are using righting aids when sailing 1up? Of course skipper weight would be helpful to scale your answers to my own weight (76 kg's nowdays <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />).
Reason for this question is that I finally managed to arrange proper weighting of my alu wing mast. My mast weighted 18.1 kg's (with internal dh and mast foot), rest of the stuff was weighted separately and were 4.1 kg's (i.e. spreaders, diamond wires, trapeze's stuff and standing rigging). Tip weight was 8.5 kg's without spreaders or diamonds. I think that it was discussed some point that wall thickness was made bigger in extrusion but difference in weights were not posted here and my mast is not a special case as Gato weighted his 18 kg's.
Valtteri
Blade F16
| | | Re: Mast weight and rightability
[Re: valtteri]
#139701 04/12/08 03:40 PM 04/12/08 03:40 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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From the top is my head my, mast fully rigged but EXCLUSING the standing rigging (= forestay/sidestay) but including halyards etc (as the mast should be measured under F16 rules) is 21.7 kg. My tip weight incl. all that needs to be included is 8.3 kg.
My mainsail is about 1 kg heavier then the newer mainsail almost entirely because I full 100% glass battens and those weight alot more the fibrefoam battens.
I can right this rig unaided (righting line) in any conditions incl very light winds and flat seas. The latter is the most difficult to right a cat in. I weight typically 90 kg or just under it. Halve way through the sailing season I'm typically between 87 and 89 kg. In some wind or waves I can right the above rig significantly easier.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Mast weight and rightability
[Re: Corksfloat]
#139704 04/12/08 10:01 PM 04/12/08 10:01 PM |
Joined: Aug 2005 Posts: 2,921 Michigan PTP
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Posts: 2,921 Michigan | I am 73kg or so and can't right my boat unless there is maybe 10 kn of wind (maybe 8ish?) without some help from someone else or an apparatus. If I weighed 7kg more or so I don't think i would have a problem. never weighed the mast though.
Last edited by PTP; 04/12/08 10:05 PM.
| | | Re: Mast weight and rightability
[Re: PTP]
#139706 04/13/08 02:19 AM 04/13/08 02:19 AM | Anonymous
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Unregistered | I am 73kg or so and can't right my boat unless there is maybe 10 kn of wind (maybe 8ish?) without some help from someone else or an apparatus. If I weighed 7kg more or so I don't think i would have a problem. never weighed the mast though. Doesn't that make it illegal for you to race single handed? How many other people are in this situation? | | | Re: Mast weight and rightability
[Re: Gato]
#139707 04/13/08 02:25 AM 04/13/08 02:25 AM |
Joined: Nov 2006 Posts: 120 Finland valtteri OP
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Posts: 120 Finland | So it takes around 80 kg's skipper (+gear) to right your boat. It would be interesting to know if that's measured with older light spar or with newer heavier mast.
Btw, I wish that we would something similar like T's mast data available online that would have helped us.
Valtteri
Blade F16
| | | Re: Mast weight and rightability
[Re: valtteri]
#139708 04/13/08 02:40 AM 04/13/08 02:40 AM |
Joined: Nov 2006 Posts: 435 Finland Gato
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Posts: 435 Finland | It’s maybe a little bit more complicated, so if somebody has the hydrostatics for a F16 it would be nice to have the GZ curves for the both cases. It’s affecting a lot more than the righting of the boat. It will also affect the capsize angle, so a heavy mast will get you into the water a little bit earlier. Me included we are 3 to small guys for the moment on this thread
Last edited by Gato; 04/13/08 03:15 AM.
| | | Re: Mast weight and rightability
[Re: Gato]
#139709 04/13/08 04:01 AM 04/13/08 04:01 AM |
Joined: Feb 2005 Posts: 1,382 Essex, UK Jalani
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Posts: 1,382 Essex, UK | I'm only 70Kg guys - so you'll understand why I like the fact that the tipweight of my Stealth carbon mast is 6.6Kg and I can right the boat unaided in all conditions. I do have to go out onto the tip of my centreboard if the wind is light though.
John Alani ___________ Stealth F16s GBR527 and GBR538 | | | Re: Mast weight and rightability
[Re: Gato]
#139711 04/13/08 05:09 AM 04/13/08 05:09 AM |
Joined: Feb 2005 Posts: 1,382 Essex, UK Jalani
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Posts: 1,382 Essex, UK | AFAIK John P charges around £500 for a blank carbon mast. Is that what you mean by transparency?
John Alani ___________ Stealth F16s GBR527 and GBR538 | | | Re: Mast weight and rightability
[Re: Gato]
#139712 04/13/08 05:17 AM 04/13/08 05:17 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | So let’s take a closer look at the case. If we have an 8 meter spar of 20 kgs and suppose that they are evenly distributed that means the centre of gravity at 4 m it would give us a righting moment of about 80kgm.
You make a modelling error. IF the above assumption is true then you would also have AT LEAST 10 kg of tipweight which we know you don't. Even if the mast is 8.5 mtr as the F16 mast are then the tipweight would still be at least be 9.4 kg. In fact the tipweight is all we need to make the righting calculations. The minimum tip weight for the F16 carbon mast is 6.00 kg, the Superwings are in the range of 8.0-8.5 kg (Valtierri's is the heaviest I know of so far. This means that the difference in righting weight between the carbon guy and the aly guy is (8.5-6.0)*8.5 = 21.25 kg. If we assume that 85 kg will do the job in all conditions then the carbon guy (of equal body length)needs to be at least 64 kg to right his boat and not 40 kg or something. In this crude mathematical theory that is as we have just totally ignored the weight of the stays + ails and the fact that water is clining to them. In fact the difference in reality will be less. Even more so when the sail is still curved and pulling the rig downwards because of the little wind that still flow across it. In fact the weight of the mast is not all the weight/force that needs to be lifted, it is only part of it. The naked spar should not be more than 15 kgs if you sail High Performance
The difference is not that much for sailing itself, it is indeed for righting. However I do agree that the F16 alu mast should be about 15 kg for the bare section. The only way to achieve that is to have a new die made. So if everybody will become a paying member of the F16 class then we may well buy a new die as a class and solve this issue. Wouter
Last edited by Wouter; 04/13/08 05:26 AM.
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Mast weight and rightability
[Re: ]
#139714 04/13/08 05:19 AM 04/13/08 05:19 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Scarecrow,
Read the F16 class rules.
It only states you must be able to right the boat unaided. It doesn't specify the way in which you need to do it. As a matter of fact, things like shroud extenders can even make the alu mast rightable by sailor weight below 70 kg.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Mast weight and rightability
[Re: Gato]
#139717 04/13/08 05:39 AM 04/13/08 05:39 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | I can not speak for Valtteri, but what I am after is a little bit more transparency in stead of protectionism. If somebody wants to buy or build an F16 he should be supplied with adequate information.
Everybody WAS supplied with correct information each time any info was asked. No-one can blame any other person for not supplying info when not asked for it. Also the fact that someone doesn't believe the info supplied doesn't mean that it is wrong or that it is part of protectionism. The argument for the alu mast was and still is that that mast is the most cost effective way to a given level of performance. At all times it was agreed that it takes more body mass to right when using ONLY a righting line. And at all times it was suggested that this issue can easily be overcome by a righting bag or other aids like shroud extenders. If you are 75 kg then a small bag of 10 liters will easily do the job. Several F16 sailors are doing it this way. When there is some wind you won't even need the bag as with the correct technique the boat will come up with much lower body weights. I'm truly sorry Gato, but it does really seem that a large portion of the way you view the situation is caused by the fact you look very negatively on the alu mast (incl. all weights and drawbacks you can find) and very favourably to carbon (ignoring all other factors in righting and limits in class rules). The core of the situation is again the tip weights (yours was 8.0 ?, Val's 8.5 kg ?) The carbon mast tipweight is at least 6.00 kg as per F16 class rules, but these tipweights already exclude 5.0-6.0 in sail weights, 1.5 kg in standing rigging and easily a few kg in water sticking to the top of the rig after a capsize. I have seen a 85 kg guy being unable to right his Stealth F16 with a carbon mast. We flipped almost simultaniously, I got mine up and he didn't. This is one indication of how important the other factors can be. They were enough to overpower a 2.0-2.5 kg tipweight difference. While there is definately a difference in righting between alu and carbon it is very easy to over estimate or overvalue it. There are indeed other factors in play that can't be ignored. Wouter
Last edited by Wouter; 04/13/08 05:49 AM.
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: Mast weight and rightability
[Re: Gato]
#139718 04/13/08 05:44 AM 04/13/08 05:44 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | So could somebody now for the transparency tell from when this die was used to make the mast and where did the old one go.
No records are kept on individual masts. As such I do not know from which batch you mast came from. The mast did come from Catamaran parts stock which may well be a portion of the VWM stock. Masts from these stocks are no older then 2004, although I know that VWM was included in more then 1 production run of masts so your mast can be well younger. In fact I expect your masts to be 2006 or younger. I don't understand the last part of your question. I'm sorry. Wouter
Last edited by Wouter; 04/13/08 05:49 AM.
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
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