| Re: AC tech
[Re: macca]
#203960 02/20/10 04:34 AM 02/20/10 04:34 AM |
Joined: Nov 2005 Posts: 69 Live in Germany, House in UK, ... DanTnz
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Joined: Nov 2005
Posts: 69 Live in Germany, House in UK, ... | Hobie seem to be the only manufacturer that prices it's parts list online Europe (in english!) the cost for a Tiger front crossbeam is over £1000, that's probably the complete assembly but then even the tiller crossbar is £200. edit: Hobie UK Parts I have seen N6.0 beams being advertised second hand at about £200 each from when I was looking for some for mine. But then we are comparing new for new here.
Last edited by DanTnz; 02/20/10 04:45 AM.
| | | Re: AC tech
[Re: scooby_simon]
#203965 02/20/10 05:56 AM 02/20/10 05:56 AM |
Joined: Jun 2001 Posts: 1,021 Australia macca
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Posts: 1,021 Australia | I wonder why Rolf didn't just order a set of beams from a current manufacturer....
Because they were more expensive than he could make them out of Carbon! Simples. A beam extrusion, even from one of the big manufacturers (at full retail) will still be a lot less than someone could build one in carbon. I understand the challenge in building your own beams in carbon, but to try and justify that its cheaper than an alloy beam is just not reasonable. | | | Re: AC tech
[Re: macca]
#203967 02/20/10 07:46 AM 02/20/10 07:46 AM |
Joined: Sep 2005 Posts: 893 waynemarlow
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Joined: Sep 2005
Posts: 893 | For reference on beams try http://www.aluminiumwarehouse.co.uk/index.html gobsmackingly cheap tube and it is delivered the next day. and for carbon tubes try http://carbonfibretubes.co.uk/ some of the big boat spinnaker poles are just the right size for us and its surprising the low cost on smaller tubes for tiller sticks etc, talk to them they always seem to have a bit laying around from a production run somewhere. Why didn't I use carbon beams on Bitsa? Carbon is a great product for tensile strength, it is terribly weak and much inferior to aluminim if hit with something sharp or given the usual sailing abuse. To protect it you must use a reinforcing glass or kevlar outer layer which brings the weight right up to that of similar Aluminium tube. Aluminium is a great product, it just doesn't have the kudos of carbon fibre. | | | Re: AC tech
[Re: Smiths_Cat]
#203977 02/20/10 10:47 AM 02/20/10 10:47 AM |
Joined: Feb 2005 Posts: 1,382 Essex, UK Jalani
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Posts: 1,382 Essex, UK | If you want to start a race with the rig canted permanently on one tack then - yes! Class rules state: 1.7.1 It is not permitted to adjust the following items while racing: the rake of the mast, the tension of the standing rigging, the angle or length of the spreaders or the position and height of the gennaker boom. 1.7.2 It is permitted to adjust the diamond wire tension while racing or to adjust the items named under 1.7.1 between the races.
John Alani ___________ Stealth F16s GBR527 and GBR538 | | | Re: AC tech
[Re: Jalani]
#204029 02/21/10 10:52 AM 02/21/10 10:52 AM |
Joined: Jul 2007 Posts: 976 France pepin
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Posts: 976 France | If you want to start a race with the rig canted permanently on one tack then - yes! Class rules state: 1.7.1 It is not permitted to adjust the following items while racing: the rake of the mast, the tension of the standing rigging, the angle or length of the spreaders or the position and height of the gennaker boom. 1.7.2 It is permitted to adjust the diamond wire tension while racing or to adjust the items named under 1.7.1 between the races. For once I agree with Macca (I feel dirty . I don't see anything there preventing canting. You can't change the amount of tension, but nothing prevents you moving the mast side to side without changing the tension. And sometimes those rules are weird: Pulling the jib halyard pulls the mast forward. Does this mean I can't adjust the jib tension on the water as it changes the mast rake? What about when I'm solo without a jib up? The halyard on my boat is still there, can I tension it? | | | Re: AC tech
[Re: Darryn]
#204038 02/21/10 04:45 PM 02/21/10 04:45 PM |
Joined: Feb 2008 Posts: 242 Brisveagas Aido
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Posts: 242 Brisveagas | Arrow cat aluminium mast section is $70au. I like to see you buy the carbon cloth for double that price.
Does seem that canting rigs would be ok under the rules. You could even use a canting system to help right the boat. Light crews would not need a righting pole or bag.
Aido Viper 288
| | | Re: AC tech
[Re: macca]
#204041 02/21/10 06:01 PM 02/21/10 06:01 PM |
Joined: Jun 2004 Posts: 502 Port Noarlunga, SA, Australia Darryn
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Posts: 502 Port Noarlunga, SA, Australia | Nope, thats why we call fore and aft changes "rake" and sideways changes are "canting"
and by having a closed loop system you can change the mast cant without altering mast rake or rig tension. If the forestay remains the same length and one side stay is lengthened with the other shortened wont that reduce the mast rake slightly? Darryn | | | Re: AC tech
[Re: Darryn]
#204045 02/21/10 06:28 PM 02/21/10 06:28 PM |
Joined: Oct 2005 Posts: 951 Brisbane, Queensland, Australi... ncik
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Posts: 951 Brisbane, Queensland, Australi... | I believe delivery costs for a full aluminium extrusion vs a roll of carbon cloth distorts the price for some ppl in certain out-of-the-way locations to the point that homebuilding in carbon becomes the cheapest option. That is the argument being put forward. Ignoring this aspect will certainly put aluminium extrusions ahead of carbon in price, but it isn't always that simple.
My personal experience was trying to buy a replacement mosquito mast a few years ago. If I lived near the major fleet it was a cheap exercise to just drop by the class stores and drive away with it for something like $300. I could not get one of these shipped to Brisbane, issues with length and fragility. So instead I had to search for alternatives locally and found a windrush mast supplier (which turns out to be very similar, it not the same), but the cost was near $700. At this price, it was nearly worthwhile building my own carbon mast, with easy availability of materials and my own labour. Maybe I didn't look hard enough for a viable transportation option.
But back to the topic. Where can I get some of that shark skin film?
Last edited by ncik; 02/21/10 06:28 PM.
| | | Re: AC tech
[Re: Darryn]
#204046 02/21/10 06:34 PM 02/21/10 06:34 PM |
Joined: Oct 2005 Posts: 951 Brisbane, Queensland, Australi... ncik
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Posts: 951 Brisbane, Queensland, Australi... | If the forestay remains the same length and one side stay is lengthened with the other shortened wont that reduce the mast rake slightly?
Darryn
yep, if the forestay to bridle connection is above the mast base relative to the platform. if they are at same height then rake will not change. the canting rotation occurs around a line from mast base to bridle (imagine a triangle being rotated about one of it's sides) this is if you measure rake from mast top to rear beam on centreline.
Last edited by ncik; 02/21/10 06:39 PM.
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