Taniwha 0 Posted July 28, 2013 Share Posted July 28, 2013 I have a carbon tube with an I.D of 50mm with a 4.5m wall and im looking to make a 2m prod pur of it on my 30foot warrick. What im trying to find out is what are the loads likely to put on the prod from a code zero and a gennaker and what do I need to do to beef up my prod in order to handle the loads. I planning on making a fixed prod with a bob stay. Should i go for spreaders also and stay them to the boat also. Any ideas on where to start would be much appreciated. Link to post Share on other sites
Guest Posted July 28, 2013 Share Posted July 28, 2013 I'd think a Code would load it more than a Genny or that's what may sailmakers are telling me. From what I've seen rather than from any engineering angle I'd say you will be up for stays. The bobstay is a good idea and my prod maker is telling me to have one, a bit as a 'just in case'. My prod will also stick out 2 mts and it's 100mm with 5.5 tapering to 3.5mm walls, which is a heavier than most as I want extra reliability for what I want it to do. There are some nicely set up stayed prods around Westhaven you can suss for ideas. Link to post Share on other sites
BNG 44 Posted July 29, 2013 Share Posted July 29, 2013 This one was 1450mm long and built of similar dimension tube for an E7.4 - http://crew.org.nz/forum/viewtopic.php?f=47&t=14081 Rotating is optional, increases complexity and difficulty in ensuring the bobstay tension is equal in the rotation so under load you really only use 15 degrees either side of centre. That might be the 15 degrees you need tho... Link to post Share on other sites
Marshy 30 Posted July 29, 2013 Share Posted July 29, 2013 The rotating really wont work on a bow as raked as that on Taniwha though. When they rotate the centre of rotation needs to be inline with the bobstay otherwise when they rotate sideways the bobstay gets looser and the prod rises. If it rises too much the sidestays end up loading up and its a clusterfuck. The one on Mercenary is good but even that lifts slightly when fully rotated, if you have it rotated and clip the tackline off on a halyard you cant straighten it without easing the halyard. So any more raked a bow than that and rotating it wont work... For offshore work i would recommend sidestays and spreaders. It simplifies the whole thing and really locks the prod in properly. And reduces risk... Gotta remember when they fail its not normally just the prod it takes out, but normally the nice brightly coloured sail hanging off it gets a good flogging too... Link to post Share on other sites
Guest Posted July 29, 2013 Share Posted July 29, 2013 I was going to write, suss BNG as he's fiddled with his protrusion. Then the real nice great guy that owns the SR26 Mercenary, Sean has a nice protrusion as well. Sorry Marshy but you don't have and aren't allowed a nice protrusion anymore even if you would be damn handy to talk to about one. Link to post Share on other sites
Marshy 30 Posted July 29, 2013 Share Posted July 29, 2013 Haha yeah that one on Mercenary was/(is for someone else now) a mint little unit! Link to post Share on other sites
Guest Posted July 29, 2013 Share Posted July 29, 2013 Haha yeah that one on Mercenary was/(is for someone else now) a mint little unit!And far more fun that what ya got now Link to post Share on other sites
Changed 10 Posted July 30, 2013 Share Posted July 30, 2013 Rotation is a nice option and gives the trimmer some more options. That15 degrees makes a huge difference. In my view though a genie does not replace a kite. It simply provides more options. Link to post Share on other sites
B00B00 310 Posted July 30, 2013 Share Posted July 30, 2013 depends on the boat richard. I agree on a boat your size but as they get bigger/faster gennakers are better. Link to post Share on other sites
Kestrahl 6 Posted July 30, 2013 Share Posted July 30, 2013 Or smaller and faster perhaps. Most of the 8m Chch boats have changed to running with gennakers over the years to increase performance and keep up downwind with the boats already converted. The thing is you need a decent length prod (2m -3m) and a running gennaker bigger than any spinnaker you can fit on the boat.. Its not all that versatile as you need another gennaker for med air reaching but it means you can take all the spinnaker gear off the boat. Link to post Share on other sites
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