X-OldHeader: From bprevett@yahoo.com-DeleteThis.com Thu Oct 16 11:51:48 2003 Return-Path: <bprevett@yahoo.com-DeleteThis.com> Received: from opus.labs.agilent.com (root@opus.labs.agilent.com-DeleteThis.com [130.29.244.179]) by jr.labs.agilent.com (8.9.3 (PHNE_25183+JAGae58098)/8.9.3 AgilentLabs Workstation) with ESMTP id LAA22390 for <wind_talk_ls@jr.labs.agilent.com-DeleteThis.com>; Thu, 16 Oct 2003 11:51:47 -0700 (PDT) Received: from msgbas1x.cos.agilent.com ([192.168.148.33]) by opus.labs.agilent.com (8.9.3 (PHNE_25183+JAGae58098)/8.9.3 AgilentLabs Workstation) with ESMTP id LAA14820 for <wind_talk@opus.labs.agilent.com-DeleteThis.com>; Thu, 16 Oct 2003 11:51:47 -0700 (PDT) Received: from web12306.mail.yahoo.com (web12306.mail.yahoo.com [216.136.173.104]) by msgbas1x.cos.agilent.com (Postfix) with SMTP id CDB4429009 for <wind_talk@opus.labs.agilent.com-DeleteThis.com>; Thu, 16 Oct 2003 12:51:46 -0600 (MDT) Message-ID: <20031016185146.55612.qmail@web12306.mail.yahoo.com-DeleteThis.com> Received: from [67.117.145.236] by web12306.mail.yahoo.com via HTTP; Thu, 16 Oct 2003 11:51:46 PDT Date: Thu, 16 Oct 2003 11:51:46 -0700 (PDT) From: bob prevett <bprevett@yahoo.com-DeleteThis.com> Subject: Fail-safing the mast base To: wind_talk@opus.labs.agilent.com-DeleteThis.com
It seems that a large percentage of "windsurfer in trouble" episodes
start with the board separating from the rig, followed by the board
moving too fast downwind/downwave for the windsurfer to catch up to it.
The board is a windsurfer's life-raft; without it, a windsurfer can get
in trouble fast offshore or out in the Bay. Preventing the rig and board
from separating does two things in case of mast base failure:
- The rig acts as a sea anchor, preventing the board from getting too far
away from the windsurfer.
- Allows the windsurfer to limp back in under sail power in most cases.
After reading about the windsurfer stranded on a cliff-surrounded beach
at the coast for 36 hours, I think it's a good time to review a few
simple techniques that can be used to fail-safe against some common mast
base failures.
1) Mast extension pulls off of cup at top of mast base:
This can happen if the mast extension does not fully engage the lock pins
on the mast base cup or if the pins break. To fail-safe against this,
tie off the end of the downhaul line to one of the holes on the mast
base cup. I use a bowline knot for this. In this way, if the extension
pulls off the cup, the downhaul line keeps the extension attached to the
mast base. Since this knot is tied above the tendon or hourglass, there
is no rig-twisting problem.
2) Hourglass or tendon of the mast base breaks:
On rubber hourglass mast base universals, there is typically a safety
strap on either side of the hourglass. This works well. After an
hourglass sheered on me once out on the Bay, I was able to sail back on a
full plane, with the safety straps keeping the mast base together. On
tendon-type mast base universals, there is a little safety line that is
supposed to keep the mast base together if the tendon snaps. Most of
these lines that come with the mast base are very weak, and get weaker
over time. So, replace the stock line with something strong like 3mm
cord from the REI climbing section or Kevlar cord..
3) Mast base slides out of mast track:
Embarrassing it sounds, this is probably the most common reason for the
rig separating from the board on the water. Obviously, double-check that
the mast base is screwed down tightly to the board before going out.
This is usually more of a problem with single bolt universals than with
two-bolt universals. The mast tracks on some boards have a little hole
at the forward end of the mast track for a safety line. And mast bases
like the Windsurf Hawaii have a hole in the foot for a safety line. So,
the foot of the mast base can be tied directly to the mast track If
your mast track does not have such a hole, you can add an eyelet
connected to some nuts to fit into the mast track, and some epoxy to hold
it in place at the front end of the mast track if needed.
4) Always double check the mast base connections before heading out: base
tight to mast track, mast base cup pins fully engaged into extension,
safety knots, etc.
5) Don't milk old mast bases too long; proactively replace old parts
before failure. Periodically check your universals for cracks, wear,
or loose bolts and nuts. Inspect tendons and hourglasses for tears and
cracks.
While there are certainly other modes of mast base failure, taking care
of the more common ones will significantly reduce the odds of loosing
your board on the water, and becoming the source for another "windsurfer
in trouble" story.
Bob
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