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Rigging
In no way am I an expert at rigging, will not calculate the load
factors per square inch on a mast, sail and rig, etc., etc. I have, hand
cranked a few swage fittings, replaced a few shrouds and stays over the years,
and seen enough "accidents waiting to happen" and those that did happen to try
and pass on some of the things I have learned. Plus, spending ten years sailing
all over the Pacific, more than once I have looked up at the masthead thinking...
this would be the worst time for that tang (I should have replaced in Fiji) to
fail!
You want an
expert, see Brian Toss's website site at,
www.briontoss.com
and a good start is his Rigger's Apprentice book and Everett
Collier's, The Boatowners Guide to Corrosion.
And about that tang? Yeah it failed, on a passage near a place called Havana Pass going into New
Caladonia, what a mess.
I wanted to add this information partly in the wake of the
tragic rigging accidents we have had here in Hawaii. Those were
Coast Guard certified small passenger vessels, but the 46 CFR regulations
for boats have only general regulations concerning sails and
rigging. You and I can look for some of these specific items. For some
history on sail rigs see the boat design site at
http://www.boatdesign.net/articles/mast-materials/index.htm
and specifics on all
the parts and pieces at the Classic Marine site in the UK
http://www.classicmarine.co.uk/Articles/Reference%20start.htm
and if you really want learn to do all the load
calculations see this Sponberg Design site in Florida
http://www.sponbergyachtdesign.com/ArticlesEngineering.htm
Mast & Booms
I won't go into masts out of column, rake, tapered, fractional rigs,
Euler's Formula, Skene's Scantlings, etc. just some basics for a good
visual inspection. Aluminum, steel, fiberglass, wood or whatever you have must
be to kept in good condition. It doesn't have to be pretty, but the paint
on that spar serves a purpose. It's at a minimum, a protective coating for
corrosion (metal masts), water and bugs (wood masts) or ultraviolet sunlight
(fiberglass masts). Usually, when I see deterioration at a spar while
conducting a survey, the paint is flaking or gone at the problem area or sometimes it easier, like the bent mast below.
Sheeves, goosenecks, tangs, fittings, boom end caps, and all those
items that make a mast or boom also have to be visually inspected. A missing
cotter pin that holds the clevis pin in place, can and probably will create a
disaster. That stainless steel fastener that was installed into an aluminum
mast without a dielectric compound or into a wood mast with a real good sealer
will fail, I just can't tell you when or what you will be doing at the time.
All those fasteners that hold the halyard winch on an aluminum stick could let
go or maybe add the "swiss cheese" factor to that portion of the mast. Without
that real good sealer in a wood mast or spreader, it can turn the new rig
wiring you bought and installed, to a useless expenditure.
Mast Steps
Lots of the masts I see are sitting in water, deck or keel stepped.
That water is in the mast step itself and shows that deteriorating
coating I mentioned. Minimum, ensure there are limber holes for the water
to get out. Next time you pull the stick, clean it up and maybe put a little
paint on the inside of the mast, and if it's a older boat ensure the support
below the mast step is sound. Deck stepped masts, after years of water leaking
into those unsealed fasteners, rot out that "core" in the fiberglass sandwich
construction and collapse it some. You can tighten to the end of the turnbuckle
and the wire is still loose. Keel stepped show some of the same problems, once
in awhile I see new a mast step on old boats, usually a new grid pattern where
the mast fits over the new step instead of in it. Same problem, where are the
limber holes for water that gets inside the mast and puddles in the step? How
about the structure below that keel step, delamination, stress fracture, split
or rotted wood? Again, without a "solid" structure top to bottom, new wires
could be a waste of money.
Wires and Fittings
I like swage fittings on 1x19 stainless steel wire, it's what I am
used to sailing lots of miles on and have worked with the most. Not sure
what grade of stainless you have, 302/304 or 316? 302/304 is not as corrosion
resistant as the 316 and as you walk around looking at 302/304 wire you can
usually see what looks like one strand of those 19 appears a little rusty or
brown. The benefit of 302/304, 1/4" wire is that the breaking
strength is 8200 lbs. - vs - 6900 lbs. for the 316 wire of the same size. Some
folks like 302/304 stainless, some 316 stainless, some dieform, some 7x19 wire,
some galvanized steel, some rod rigging, and some the new kevlar, but the
basics on what to look for are the same, ANY DETERIORATION! Any broken stands,
cracks, kinks, or stretch on a wire, rod or its fittings, replace it. Brush
away any rust on a fitting, toggle, or turnbuckle and look real close. Look
at the hole the clevis pin is in on the chain plate, is it round or oblong?
Oblong means point loading. What you are seeking is the weakest link in the
system.
Look at the clevis pin, is it the correct size? I have seen more than one rig where the wire, turnbuckle, Sta-lok or swage fitting and toggle are all set up for ¼" wire but the clevis pin is 3/16".
I also have seen folks try to "game" the system, meaning if the
original specifications are for ¼", 316 wire, let's go 2 sizes up
5/16", 302/304 wire, and make it bullet proof! Doesn't work like you
think even though that mast is designed with a built in "safety factor". From what I
have read a 3 or 4 to 1 factor on most masts, some are 100 to 1(heavy wood maybe), and from the mast snappings of
some of those "racing sleds" it appears to be a 1 to 1 factor.
Without knowing the detailed information of the design parameters, your
gambling. First when you "tune" (tighten) a rig wire usually to 10% to 15% of
its breaking strength that would mean 690lbs. to 1035 lbs. for 1/4", 316 type. Now you change that same shroud to 5/16" size and 302/304 wire and that 10%
/15% rig tension is now 1250lbs. to 1875 lbs., almost twice the downward pressure on the mast or maybe like sailing in a 20
knot breeze, sitting at the dock, without any sails up? If that mast has a built in safety structural breaking factor, what did you just do?
Adding bigger wires has added more compression loading
to the mast and more tension to everything it is attached to, so
what happens to the load factors when you get caught in a 30 knot
blow? I have seen a wood boat pop a bottom plank and destroy the structure
below step, a fiberglass boat trying to drive the mast thru the hull, etc.
Thinking about doing that, check with the boat builder or a Naval
Architect first, it might make a difference if you get out there in really nasty weather.
SAILS
When I look at sails during a sea trial, I look at stains, holes, stitching, chafe, and stretching. Some sail makers are masters at their work and can take what looks like a worn out sail and get you a few thousand mile more. Adding or reducing roach or re-cutting the foot can get you a faster or better ride or both. The sails are the horsepower for the vessel and sometimes part of the steering and suspension.
On really long passages in the Pacific you get to "play" with sheets, you move the car forward 1 foot or sheet in 2 feet and "ooooh that's nice". It's all about sail shape when the wind is in it. Generally, I look at the slot (empty space between the sails) and see what wing shape it outlines.
Here is a UK site all about
sails, how there are made, flown, trimmed, etc.
http://www.ukhalsey.com/LearningCenter/encyclopedia/encyclopedia.asp
Don't know the sail area for your boat and want to see
those load factors? See one of the many sail area calculators on the
net at
http://www.image-ination.com/sailcalc.html
Then you can go to this site, just go to Wind Load, scroll to wind loads and plug in the math.
http://www.sailingusa.info/motion_comfort.htm
Here's a good site for rigging information, how it's made, breaking
strength, fittings, etc.
www.loosco.com
and a Navtec site for the new "fiber" rigging at
www.navtec.net
and Aussie site for the how to on the Norseman and
Stalok fittings at
www.mauriprolsailing.com/Sta-Lok/stalok-fittings-instructions.htm
Rig inspection guide at
http://www.boatus.com/seaworthy/rigging/default.asp
Turnbuckle etc, guides at
www.hayn.com/marine/rigging/index.html
http://www.harken.com/
Travelers, Halyards, Vangs, Winches, Cars, etc.
The same vigilance in the visual inspection is required and nothing
wrong with grabbing part of that system, shroud, track, car, etc. and pulling
on it. Sometimes it's the only way I find out it's history but couldn't tell by
just looking.
Contact me:
Phone: 808-375-8260
Bob@BoatSurveysHawaii.com
Bob Dupuis
Marine Surveyor/Consultant
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