From: kell@mprgate.mpr.ca (Dave Kell)
Subject: Tricky docking
Reply-To: kell@mprgate.mpr.ca (Dave Kell)
Organization: MPR Teltech Ltd.
Date: Wed, 7 Oct 92 19:46:35 GMT


In the spirit of John F. Hughes' "hypothetical" problems, I have one from
real life.

This summer I managed to screw up a docking manouvre and hit another boat
for the first (and hopefully last) time.  No real damage except my ego...

I was attempting to dock on a club float which is usually affected by 
tidal currents.  The current is in line with the dock, and this time the
wind was against the current, at about 15 kts.  The current runs from
0 to about 1 knot here, always the same direction.

Here goes the ASCII art:


       DDDDDD  B
       DDDDDD BBB       |
       DDDDDD BBB       |  Current
       DDDDDD BBB       |
       DDDDDD BBB       V              The DDD is the dock
       DDDDDD BBB                      The groups of BBB are other boats
       DDDDDD                          The ... are my route in to the dock
       DDDDDD
       DDDDDD
       DDDDDD
       DDDDDD
       DDDDDD
       DDDDDD       .
       DDDDDD BBB    .
       DDDDDD BBB    .
       DDDDDD BBB     .
       DDDDDD BBB     .
       DDDDDD BBB      .              /|\
       DDDDDD BBB      .               |  Wind
       DDDDDD  B        .              |
       DDDDDD           .              |


The problem was to dock in the open spot on the dock, which was only
a bit longer than Covivant (maybe 6 feet extra).  People on the dock
assured us there was room for our boat.

Before making our approach, we put the engine in neutral to see whether
the wind or the current had more control of us.  To my surprise, we
drifted with the current, into the wind.  I concluded from this that
we'd be better off approaching from down-current, since it's really
hard to stop the boat against the dock with a tail current.  Also, our
stern pulls to port in reverse.

I made the approach quite slowly, running nearly parallel to the dock,
but with over a knot of boat speed through the water.  I checked a few
times on approach, and was convinced that the wind was parallel to
the dock.

Nonetheless, once I had the bow in the hole between the boats, it became
apparent that the boat was moving towards the dock faster than the stern
was passing the windward boat.  I couldn't turn out to abort the approach
because the stern would swing into the windward boat.  If I turned to port,
perhaps the people on the dock could have walked the bow up-current, but
I think the stern would have swung into the windward boat also, plus the 
possibility of hitting the dock hard.

In the end, our lifelines in the cockpit got caught on the windward boat's
trolling gear (no he wasn't fishing), the people on the dock took our bow,
and we pushed clear of the other boat.  After having done it, our conclusion
was that we shouldn't have attempted the approach at all, but anchored out.
However, my question is, was there something I could have done to minimize
the error, once I found out I was drifting in too fast?

Two points of note: 

a. Two weeks before, under pretty similar conditions, I watched someone 
   else do exactly the same thing on this dock, and he got caught in the
   anchor of the upwind boat.

b. After thinking about it, I realized that slowing down the boat speed
   changed the amount of effect the current had on the boat.  If I had
   approached at a constant speed, I wouldn't have been caught.

dK
===========================================================================
Dave Kell   (604) 293-5753                 kell@mowgli.mpr.ca
MPR Teltech Ltd.                           mprgate.mpr.ca!kell@uunet.uu.net
8999 Nelson Way
Burnaby, BC, CANADA
V5A 4B5
===========================================================================
Newsgroups: rec.boats