# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

### Compose Your Message

Message:αβγ
Message:abc
 Add Images & Files Posting Code: Name: Email:
Re: Logs
From: Jared Sherman
Date: 2003 Jun 10, 15:50 -0400

```Vic-
I think this is one instrument where construction is highly a matter of
convenience. The boards I have seen pictured are triangular in shape, perhaps
4"-12" along each side. In each corner you drill a hole and attach perhaps 3'
of any convenient light line, i.e. "parachute cord". Take those three lines
and even them out (i.e. stand on the board and pull all three up over the
center of it) then tie a knot where they join. You could insert a ring at
that point to join it up to your knot line, or simply tie the line on.

In this age of synthetic cloths, I would think "ballistic nylon" or any heavy
synthetic canvas could be used instead of the wooden log, just like a very
small sea anchor, with a fishing weight on one corner perhaps to make it
submerge promptly.

The knot line can again be any convenient cordage with a knot tied every
increment along it. The increments can also be at your convenience, so you
can measure only full knots, or place one every 1/10th of a knot (10x more
often) etc. Instead of actually tying knots in such a long cord, consider
just putting a stitch of yarn through it to mark every position.

The distance between knots would be simple math: One "knot" of speed being one
nautical mile per hour, which is 6076.115 feet of line that would pass
through your fingers in one hour.

Dividing the ungainly 6076.115 feet of line by 60 (the number of minutes in
one hour) we can arrive at 101.27 feet of line that must pay out in one
minute, to measure a speed of one knot. Or 50.56 feet of line between the
physical knots, to measure a speed of one knot in thirty seconds.

You can, after all, stream the line out for a full minute or any convenient
portion of it. This is custom instrument building and your preferences rule.
I would encourage you to build your line literally on the scale that suits
your boatspeed and patience.

If you are on a sailboat making typical speeds of perhaps 6 knots, that is
36,456 feet traveled in one hour. That could require hauling in 607 feet of
line in one minute. Or, 303 feet in thirty seconds, or 151.5 feet in fifteen
seconds. So, you can place your physical knots at whatever distance makes
them scale nicely for the time frame you plan to use.

In order to calibrate your line for tenths of a knot, simply place ten knots
equally along each "knot" worth of line. Or a hundred tiny knots, if you want
to be really compulsive about it.

Don't take any of my math for granted...I'm not licensed to practice it in this state.

```
Browse Files

Drop Files

### Join NavList

 Name: (please, no nicknames or handles) Email:
 Do you want to receive all group messages by email? Yes No
You can also join by posting. Your first on-topic post automatically makes you a member.

### Posting Code

Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
 Email:

### Email Settings

 Posting Code:

### Custom Index

 Subject: Author: Start date: (yyyymm dd) End date: (yyyymm dd)