advice on Loran C

[Catcher's Mitt]

I need help from one of you ole salts out there. i know nothing about Loran C. i do have about 15 pages of Loran numbers that i got from a neighbor that got it from his guide friend who was retiring. i got these about 20 years ago and have not looked at them since then but have them in a file.

i got a call from a buddy that says we are heading west then south for some overnight fishing this weekend. we will be in this area for everybodys first time. it is in the area where all these loran numbers are.

is there anyway in hell to fish any of those old wrecks and reefs that are marked in Loran C on those pages?

Thanks

Mark

[Bert Rodgers]

1st off you need to know that all LORAN signal transmitters have been shut down perminately so loran recievers are basically useless now. LORAN #s that have been entered into a GPS chartplotter that features a logrithmic conversion can still be useful but may not be accurate.

Bert

[Catcher's Mitt]

1st off you need to know that all LORAN signal transmitters have been shut down perminately so loran recievers are basically useless now. LORAN #s that have been entered into a GPS chartplotter that features a logrithmic conversion can still be useful but may not be accurate.

Bert

i guess that rules out buying a Loran to use.

So if the the boat we are going on has a chartplotter that has that capacity, we might be able to get close? will it be a factor....like any one we put in, the closest we can hope for is 300 yards. or will some be more and some be less?

[Glenn W]

i got from a neighbor that got it from his guide friend who was retiring

Who knows if the numbers you have are even accurate using a Loran (if that were possible). That being said, assume they are dead on accurate Loran generated numbers. If you have a fairly new GPS (with a newer GPS/loran algorithem ) you may or may not find the spots. For a specific wreck or rock pile you may spend more time looking than fishing. For a good size ledge, it may be big enough to find. For a trolling area, they should be close enough for government work.
You will need to know what loran "chain" to use and put this in your GPS --- sorry I don't know the Chain for the Gulf. Secondly, do some searching on the internet, etc for the "Loran Offsets" for the area you'll be fishing. These offsets are critical for narrowing down a spot using the GPS converstion. This is due to the algorithum used by the GPS and the fact that real Loran TD's are non linear (straight lines). With good offsets, you should get pretty close, but no guarantees.
One tip on finding offests: go to a known location (such as a bouy) that has both lat/long AND TD's listed. Actually go to the bouy and note what your GPS says the TD's are. Compare this with actual TD's taken from a good Loran in the past. The difference should get you real close to the required offset you need.------ Note: in your GPS there will be a provision to put in loran offsets as + or minus amounts for TD correction factors.

[TunaTeaser1]

Second Glenn on the offsets. I think with the conversion you will get decently close if you have the right offsets, but 300 feet will probably be as accurate as it's going to get.

[clt_capt]

Unfortunately the best way to handle Loran to GPS translations was to have both Loran and GPS on your boat, go to the loran Waypoint (TD) and punch that into your GPS...

Since Loran is no longer functioning, you need to set up your GPS to provide Loran translation WITH the offset - and then do some scouting with your bottom machine. Once you find the structure, enter it into your GPS...

[Jiggin Junkie]

The proper offsets are the key. If they are not correct for that specific area then you could be as far as 1/2 mile off. I know bwcause I ran both on my boat until they shut loran down in Feb of this year. If you are looking for a small piece of bottom and you are 1/2 mile off then you will be there a long time finding it, that is if you do find it.

[seapower]

This is just what I've seen, can't speak for anyone else. I have 2 GPS plotter unit's (both stand alone) on my boat, both are Furuno unit's. I have had 2 other brand's on the boat at the same time I had my original Furuno unit. The other brand's did not read the same(not even close enough to find the structure) as the Furuno and the Furuno was proven in my mind to be the closest to converting TD's to lat/lon. I now have 2 Furuno unit's and they read to the tenth of a microsecond to each other. Myold bottom number's are in TD's (loran) and I do have to do some looking for known area's or point's of interest. But using just the Furuno unit's has cut my looking time way back. Once it's found with the new unit's, I can come right back to them. Not all brand's have LORAN compenstation abilitie's, some won't even give you TD's. GPs plotter's also need to be "adjusted" to your area, these adjustment's have known value's. Our local Furuno dealer does a great job setting our machines up, I might add. I will also add that when I commercial fished Furuno was the brand of choice. In my mind it still is. I guess what I'm saying is that they aren't all created equal, just my experience. Frank

[captnemo]

Buy the largest scale chart for the area you wish to convert, 24$ from NOAA at any boat store, plot the loran numbers, and pick off the lat and long.

[Glenn W]

Buy the largest scale chart for the area you wish to convert, 24$ from NOAA at any boat store, plot the loran numbers, and pick off the lat and long.

I may be wrong but it is my understanding the the Loran overlays on even the most detailed Noaa charts claim accuracy of +/-.25 minutes or about a quater of a mile.