Monday, June 24, 2013

The old ways are still good


There is a lot of commercial traffic on Puget Sound.  There are big container ships, cruise ships, ferries, tugs towing barges, and military ships.  And all of these move faster than we do in Eolian - much much faster.   Whenever we cross the traffic lanes, I feel a little like the frog in Frogger.

There is a strong tendency on my part to be attracted to the latest new, shiny "gee whiz" gadget.  I'm pretty sure that I am not alone in this.  But you have to go pretty far up the gadget cost scale to get something that can top the good old hand bearing compass. 

A recent crossing from Port Madison to Shilshole provides the case in point.  Just as we cleared Jefferson Head, a tug and tow became visible, heading south in the southbound traffic lane.   I pulled out our trusty old hand bearing compass and took bearings on the bow of the tug and the stern of the barge it was towing.  Then after a few minutes I took the bearings again.

The old adage is that if the bearing is not changing, then you are going to collide.   And tug-'n-tows are long enough that you need to keep track of both ends of the combination (NEVER try to go between a tug and its tow!).

But when I took the second set of bearings, I noticed that a second tug and tow had  appeared from behind the first - he was in the process of passing!   The problem just got more complicated.

Clearly one tug was going faster than the other (he was passing, after all).  Now the choices had become:
  1. Pass in front of the entire parade
  2. Pass between the barge in the first tow and the tug in the second
  3. Wait for the whole parade to pass and cross behind the last barge.
More study with the compass as we continued, our courses converging, convinced me that choice #2 was available to us, but that we were going a little too slowly to make it possible.  So I increased our speed (there was no wind - we were under power), and confirmed that we could pass between the first barge and the second tug.  A little more fiddling with the speed got us into the sweet spot.  And indeed, we cleared both tug-'n-tows nicely, with no drama at all.

We did this bit of piloting with a lowly hand compass. 

To do it with electronics, you'd need to have a GPS-interfaced AIS receiver, or a multi-thousand dollar radar with MARPA capability.

Or a hand compass.




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4 comments:

Anonymous said...

and I 'm sure the hand compass let's you be exact, but my 'old ways' are to take a good look at the bearing relative to me and my boat. I seem to be able to do this by 'eye' and it hasn't failed me yet. If the difference is close enough to be measured in just a few degrees, that is too close for comfort on my boat.

middlebaysailing said...

The old ways work very, very well. This was underscored for me again in May when I sat on my hand-held GPS and broke the screen. We hadn't arrived at our destination yet (90 miles from homeport), and had the entire distance to travel back after the event we were attending. There were absolutely no worries with a bulkhead compass, hand-bearing compass and charts.

We've crossed the Chesapeake shipping channel many times and it's always a bit of an anxious moment if we are crossing in front of a ship. The hand-bearing compass is the easiest tool to use and understand for determining go or no-go - lucky for me, because I can't afford the technology solutions!

Fixed Carbon said...

Option 3.5, slow down and let them pass.

Robert Salnick said...

Fixed -

...actually, that was option 3...

bob

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