Question about navagation lines

sherry marie · 06-02-2003, 02:51 PM

Another question from a "not so experienced". When speaking of a location off the coast sometimes it is refrenced as "we were on the 70 line in 40 fathoms of water" or some other number. What does the line refer to?

Ray

tailchaser · 06-02-2003, 03:03 PM

If you look on a seachart used for navigation they have multiple lines on them. Some used to be used a lot by Loran users back in the day, but they are latitude and longitude numbers used mostly now. You'll here people refer to the 124, and 125 lines also. Look on that chart and see these lines running North, South. The depth is the fathoms, 6 feet to a fathom, so they would've been in 240 feet for 40 fathoms. Most of the commercials use a North, South tack when fishing also so they'll refer to the line they are on.

tc

Pilar · 06-02-2003, 03:07 PM

Sherry Marie, the common vernacular when consulting charts is "I was on the XX fathom line".

This means that the fisher went west to a specific depth and then went north or south and followed that depth. Most charts have a series of bathyscopic lines (like elevation contours on hunting maps but in reverse) that trace the point where the water is a specific depth.

Common 'lines' are 20, 30, 40, 50, 75, 100, 200 and so on.

It is also a polite way of not giving an exact location :grin: .

Fish like Salmon will congregate at a specific depth for feeding purposes. So if you report fishing on the 75 fathom line and your gear is at 40 fathoms, that is pretty informative.

Look at the chart, knowing the port of departure and find the closest depth that was mentioned, noting the location of the contour line for say 75 fathoms. Mark a few waypoints along this line to steer for. Then I would go west in the boat, looking for 450 feet deep water and run the downriggers down to 240 feet to fish.

sherry marie · 06-02-2003, 04:50 PM

THanks I knew that I could get the answer from you wise ones. We were fishing out of Depot Bay on Saturday. WOnderful weather but the action was slow. We had one average Chinook in the box, lost one and one silver throw back. Listening to the chatter on the radio I could not figure where the #s were. We could see boats around us but I was looking for a Lattitude line on the chart and a contour fathom line not a fathom line on the chart and a downrigger depth. BTW we put a very nice nook in the boat on fri afternoon but we had lots of flounder and black cod hindering our effort.
Fishing is learning and I have learned alot from the contributors here on the Salty Dogs site. Its sure nice to have help and a kind word of advice Thanks Much

Ray on the Sherry Marie

fish assassin · 06-03-2003, 06:09 AM

Ray,

When you hear the guys out of Depoe Bay refering to the "800 line" or
the "740 line" at 50 they are talking about loran numbers + fathoms. The
800 line is off Cape Foul Weather.

I wish I could get my Raytheon Machine to give me numbers in TDs instead of
Lat/Lon. All the charters and most of the commercial guys in our fishing area
use TDs. It's so frustrating not knowing!!

-assAssin-

WP · 06-04-2003, 10:06 PM

FA,
You can buy a program that converts TDs to Lat/Lon (though not too accurately as each Loran is pretty unique) there are also GPSs that function in TDs as well as Lat/lon and other frames. They are the high end machines mostly. The software to convert is not cheap...thus I didn't get it. I have a ton of old TD locations I would dearly love to convert! Such is life. If anyone does get the software, I would trade locations for translation! I would actually be happy to share the TDs but they won't help most people in that form anyway. :depressed:
WP

Scaup · 06-05-2003, 06:03 AM

FA,

If you want a "relatively" inexpensive GPS to put on your wish list for a back-up that will work with TDs try the ICOM ML-270. A month ago Boaters World closed out their inventory of 270s and sold them for $149! I know that doesn't help you now, but you can pick one up for $229.

http://www.thegpsstore.com/cgi-bin/S...891+1045188857

[ 06-05-2003, 07:12 AM: Message edited by: Scaup ]

Mark Mc · 06-05-2003, 06:47 AM

Or just look at the chart.

Popeye · 06-05-2003, 07:00 AM

WP...I just ordered that GPS...I'll let you know when I get it! :grin: