NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: USS Fitzgerald collision with container ship
From: Gary LaPook
Date: 2017 Jun 20, 16:50 +0000
From: Sean C <NoReply_SeanC@fer3.com>
To: garylapook@pacbell.net
Sent: Monday, June 19, 2017 10:10 PM
Subject: [NavList] Re: USS Fitzgerald collision with container ship
From: Gary LaPook
Date: 2017 Jun 20, 16:50 +0000
Oh, way back in about 1980 I wrote a program for my TI-59 programmable calculator (with the little magnetic slips) to solve that exact problem.
gl
From: Sean C <NoReply_SeanC@fer3.com>
To: garylapook@pacbell.net
Sent: Monday, June 19, 2017 10:10 PM
Subject: [NavList] Re: USS Fitzgerald collision with container ship
Frank Reed wrote:
"The simplest scenario would be that they were trying to cross over to get on the other side of the container ship's track and someone simply mis-judged the distance and speed."
Coincidentally, at the time this story broke I was working the maneuvering board problems from Pub. 217 (the NIMA Maneuvering Board manual). Specifically, example 7...which is exactly this scenario: a ship is observed on radar on a collision course with one's own vessel. "It is desired to pass ahead of M [the other ship] with a CPA [closest point of approach] of 1.5 nautical miles."
The solution to this problem on a maneuvering board is pretty simple. It would seem to me to be a trivial exercise in coding to write a program which could make recommendations on speed and course changes based on radar contact data. And I would expect that if such a program did exist, an outfit so heavily reliant on modern technology as the U.S. Navy would be making use of it. Or, perhaps the Navy needs to place more emphasis on the benefit of using the humble maneuvering board, in addition to their reintroduction of celnav instruction.
Frank also wrote:
"...the Fitzgerald's course at the instant of collision was about 115° or east-southeast."
Wouldn't that actually be "southeast-by-east three quarters east"?
;)
-Sean C.
