Keep mast raised when not in use?
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Posted: May 19, 2008 - 02:28 PM
I am looking at keeping my 1982 Hobie 16 at a marina where there are a large number of other cats (Hobies, Nacras etc.). The boats are kept on special made floating docks so they can be easily slipped into the water. My question is would it be okay to leave the mast raised for the season? The thought of trying to raise the mast on a floating dock is not appealing, even with a assistance. The other boats I saw there all had thier masts raised, but I remember reading that the mast should be lowered when not being sailed. Any input would be great. Thanks! -
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Posted: May 21, 2008 - 04:38 PM
We keep ours up all season long - but our nacra is on a trailer - mast movement will cause wear and stretch on your shrouds - put a bungee between them and keep them tight - otherwise just replace them every couple of years
Have fun
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Gordon
Nacra 5.5SL
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Posted: May 22, 2008 - 10:06 AM
Stainless cable, providing it is not the thickness of thread, will not be damaged by the cycling of the mast due to wind. SS will not be affected by UV either. If you have 1/8th inch (rated at 1500 lbs tensile) or thicker shrouds... they will virtually never wear out. The attachment points may eventually wear on the mast... but it takes a LONG time and is often the result of aluminum touching stainless electrolysis encouraged by high humidity and salt air.
Deepsees -
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Posted: May 22, 2008 - 06:16 PM
are you actually saying that rigging does not stretch over time? - I guess all the rigging companies and cat sailors are just lying to us.
I personally have witnessed shrouds that have stretched over time.
Salty dog marine and west marine must just be full of it!!!
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Gordon
Nacra 5.5SL
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Posted: May 28, 2008 - 10:12 AM
There is a thing called the modulus of elasticity in metals. That means that the metal in topic will stretch when loaded and will return to it's original length/size as before stressing so long as the M/L has not been exceeded.
When a cat is under use and hull flying, it has it's maximum load applied. Since most 18 foot cats toe in at around 700 lbs with crew... a 1/8th stainless cable rated at a 4:1 ratio is good for 1500 lbs.... modulus of elasticity is not reached till 6000 lbs of strain.
We are to believe that the next to nothing loading (less than 20 lbs avg) of a cable will stretch a cable with a M/L of 6000 lbs?
If there is any form of elongation taking place over time it is not a cable stretching. The sun will cause the cable to grow as the day heats up... but again... the ML will be observed at sun down.
Metals are my business. What's yours?
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Posted: May 28, 2008 - 01:02 PM
Engineering.
a mast with loose shrouds let to stand upright for a period of six months in a state where the wind can reach 70 mph on any given day.
and you are telling us that nothing happens?
we are talking about storage of a boat with the mast up - ie. no crew attached.
Standing Rigging Basics
For starters, there's no hard and fast rule about how often a boat needs new rigging. The only rule is this: eventually it all needs to be replaced—wire, toggles, turnbuckles, clevis pins, swage fittings, and couplings. Standing rigging will obviously last longer in relatively benign, freshwater environments. In the semi-tropics, however, many surveyors recommend that rigging be replaced every 5 years. Most rig failures are caused by corrosion, which can lead to metal fatigue. Rigging professionals say that 99 percent of the time the lower terminal is the weakest link. While on rare occasion the wire itself can also fail—usually due to an alignment problem or a wearing problem — the bottom line is vigilance when it comes to keeping the rig up.
enough said...
I was trying to help the guy not give him a college education on metal fatigue
Good Luck
edited by: ghhm43, May 28, 2008 - 12:20 PM
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Gordon
Nacra 5.5SL
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Posted: May 28, 2008 - 05:34 PM
Being an engineer.... seems like you would know about M/L. We stress test metals. If you are telling us that stainless steel with 6000 lb M/L will stretch and stay stretched by the task of keeping a 28 foot mast erect, I suspect your degree came through the mail. Unless it is kinked and a stand breaks as a result, SS will be here long after we are gone with the wind and in good service.
I have had my cat for ten years now, everything not glass or aluminum is stainless. No wear detectable. The only thing I have had fail is a weld on a chain plate. That is a whole different situation.
I am telling this guy that he can leave his mast up if he has SS wires. Nothing will fall within the next hundred or so years as a result of the wires being stressed. Even in 70 mph wind.
That is why aircraft uses it.
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Posted: May 28, 2008 - 05:46 PM
I'm not here to start wars... thing fail - stainless or not - planes fall from the sky too..
Ok - you win I'm not even going to waste my time insulting you. But you might want to take a refresher class.
Don't see you manufacuring for the melges and nacras of the world 
May you demast next time your out.
edited by: ghhm43, May 28, 2008 - 05:36 PM
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Gordon
Nacra 5.5SL
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Posted: May 28, 2008 - 09:05 PM
I am 64 years old and have been sailing cats since 1976 (from P-16, P-19, SC-20 to present Nacra 6.0)) and all but 2 years have had the mast up 12 months a year with no ill effects. I change my rigging every 3 years (no friggin with the riggin). Don't spend time over analyzing. GO SAILING -
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Posted: May 29, 2008 - 03:14 PM
Ok I'll jump in as engineer #2. There is a difference between the SS shroud wires failing from stress and the whole shroud failing to function. The likelihood of the shroud wire failing under stress is, as stated, next to impossible(barring abrasion, or crimping). However, a lot of things can go wrong around the wire, as stated, the most common being the wire to lower terminal connection. That can be avoided by inspection and regular cleaning.
I looked at a boat whose owner proudly displayed his oversized shrouds. Later he was telling me how the bows came up in a wind, he had no idea how top heavy he had made his boat in the fear of having those skinny little wires break.
Changing the shrouds every three years will guarantee a low likelihood of shroud failure but what a waste.
My '88 H21SE is on the original shrouds and headstay, not even any signs of wear, only slight discoloration. Mast is up all season but all lashed down to prevent movement and rotation, easiest way is to tie off the boom and tighten the rotator line.
Just for you non-engineer types, dirty little secret about metals. Iron based metals, steel SS, etc. will not fatigue fail under repetitive load/unload cycles unless you you surpass the yield point, which is way up near it's failure. Aluminum, however, is a different beast and can suffer fatigue failure at loads much closer to its ultimate strength. That's why the shrouds aren't aluminum and the mast is. -
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Posted: May 29, 2008 - 05:21 PM
In reply to the 1988 H21SE with original wires, I promise you that if you kept your boat on the beach year round as we do, You would surely have been demasted by the year 1991 or 1992 at the latest. Futher more, I would advise against using factory made wires for most boats. Some manufactures have begun using cheap SS wire from less than ideal Asian sorces. It is best to get them made locally using Mil/Aerospace spec wire made in the USA or EU with genuine Mil/Aero spec thimbles, ovals, forks. Demand that all fittings are packed with 3M 5200 or a similar before swaging so that water never intrudes into these anaerobic environments to eat away at the rigging. I had mine made for my nacra 6.0 locally this way and it was actually close to $100 less than the manufacture and I knew exactly what I got. It is uninspected and uninspectable parts of the rigging, the real reason we change so often -
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Posted: Jun 02, 2008 - 11:07 AM
I think I will leave it up.....hahaha...Thanks. -
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Posted: Jun 02, 2008 - 11:07 AM
I think I will leave it up.....hahaha...Thanks. -
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Posted: Jun 02, 2008 - 11:34 AM
I only keep it at the shore for the summer and very aggresively de-salt it when it's inland. As far as "some" manufacturers I can't say. But overall, this Hobie is a quality built product, from hull, to tramp, to sails and rigging I've enjoyed excellent durability with no signs of anything but very high quality components. It may be that things have changed, this is a twenty year old boat, and much heavier than it's modern counterparts, but I'm very pleased with it. I will definitely, at the first signs of any type of detrioration of the rig, replace the stays. I inspect it very carefully and see no reason for it at this time. -
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Posted: Jun 16, 2008 - 12:27 PM
How much slack should there be in the forestay or shrouds. This is my second time as a H16 owner and it has been a long time.....As I remember, the shrouds were a lot "tighter" thatn the ones installed on my current boat (1977 H16). I understand that there should be some to allow for rotation and such, but there seems to be more than necessary. The adjusters are set to the next to bottom hole.
Thanks.
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Birdlaw
H16
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Posted: Jun 17, 2008 - 09:32 AM
Forestay slack is adjustable on some cats. This allows tuning of the rudder to either be a weather helm or not. Meaning the tighter forward the mast is the less tendency the boat has to turning into the wind when the tiller is let go. Weather helm is good if you tend to fall off your boat...it will turn into the wind and "stop".
I have never sailed a hobie... not familiar with their hardware.
edited by: Deepsees, Jun 17, 2008 - 02:33 PM -
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Posted: Jun 17, 2008 - 10:44 AM
From what I have read and understand is that when the shrouds are fully loosened if you grab the wire with your hand and then rotate your hand left (if right handed), you should be able to get almost a 90 degree rotation. If all wires are tightened up rotation should be about 45 degrees. I originally thought that I had the wrong size wires for my cat, but read this. It could be a internet rumor, who knows!?!?
I have seen in the past and am trying to get a chart for wore setups and wind speed, which would help get a ballpark idea of proper setup.
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Posted: Jul 29, 2008 - 03:01 PM
I kept my H14 turbo in a dock slip for 5 summers on a busy lake. I created a three point tie off to keep the boat from moving and used dock bumpers. My mast & rigging showed no ill effects although I had to bungee my hailyard to keep it from flapping and annoying the neighbors. I did set the rigging tight to minimize mast movement.
Replace regularly and tape your spit rings though! Those are what will go before your rigging does! I learned this the hard way leaving my N5.8NA Mast up last winter on the beach. Fortunately it came down to lean against a row of wooden lockers and did not rip out the mast pivot or worse.
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