Wreck Numbers

[Paleface]

I have a Lowrance GPS,offshore map of Del. Md. coast, Internet site with md del wrecks all of them give different numbers for the same wrecks. What are we suppose to do go out and find the wreck ourselves and chart them????

 

[dannobee]

How far off are the numbers? And how big are the wrecks?

 

[lowviz]

I have a Lowrance GPS,offshore map of Del. Md. coast, Internet site with md del wrecks all of them give different numbers for the same wrecks. What are we suppose to do go out and find the wreck ourselves and chart them????

loran is an old land-based transmitter system. LORAN-C General Information - USCG Navigation Center Its accuracy is relative to where you are with respect to the towers. Basically it gets you close enough to plow the ocean with sonar to find the wreck. Converted loran numbers are notoriously inaccurate. GPS is a satellite system that is dead-nuts on. The captains that I know all have their own suite of private numbers that gives them their individuality. Many of these snag numbers from fishermen and draggers were hard to come by. You are meeting with resistance because you are actually asking people who make their living on the water to just give you the numbers so you can head out early and beat them to the best tie-ins. Additionally, there may be more than one wreck with the name you are looking for. The "Mohawk" is at least three wrecks. So without being a wise-ass, the answer to your question is "Yes." With this post I return to lurking.

 

[Paleface]

Dannobee- I understand what your saying but some of the numbers are up to a mile off.

Lowviz- If you reread my post I have a GPS and I am comparing GPS #'s from all three and as you put it they are dead nuts on
At no time did I ask anyone for numbers, and I will find them on my own. I would just think when you spend the money to buy a chart or gps unit with a charted map that it would be accurate!! I was just wondering if anyone else has run into similar problems.

 

[lowviz]

Lowviz- If you reread my post I have a GPS and I am comparing GPS #'s from all three and as you put it they are dead nuts on

I read it carefully the first time. Dollar to a doughnut that you have a couple of collections of converted loran numbers that agree with each other, all having started with the same loran c reading.

 

[rjack321]

Dannobee- I understand what your saying but some of the numbers are up to a mile off.

Lowviz- If you reread my post I have a GPS and I am comparing GPS #'s from all three and as you put it they are dead nuts on
At no time did I ask anyone for numbers, and I will find them on my own. I would just think when you spend the money to buy a chart or gps unit with a charted map that it would be accurate!! I was just wondering if anyone else has run into similar problems.

Confirm that they are all using the same datum. Confirm that this datum is the same as the paper chart. Plot the numbers on said paper chart with calipers and a ruler, make an educated guess about which ones to try mowing the ocean over first. Yes you gotta work for the dive.

 

[Nemrod]

I have run into this over and over. I have come to the conclusion that some of it is purposeful. Fisherman are notorious liars and may provide erroneous numbers which are then picked up and spread about as gospel. Another aspect of this is that storms do in fact move things around. Another aspect is that locals have different names for the same features and often use the same names for more than one feature. So this gets confusing to outsiders who then mix everything up. Names also change over time for the same features.

Further, with three GPS units on-board I have occasionally had a split that I cannot explain. All I can say is that you should use published numbers with some due caution until verified and once verified re-verify after a severe storm or legit of time.

N

 

[rjack321]

I have run into this over and over. I have come to the conclusion that some of it is purposeful. Fisherman are notorious liars and may provide erroneous numbers which are then picked up and spread about as gospel.

Yeah fingers get surprisingly fat when it comes to publishing lat/longs.

 

[dannobee]

Dannobee- I understand what your saying but some of the numbers are up to a mile off.

OK, what we do when using someone else's "numbers" is to verify the numbers with some depth soundings, ie, if the bottom's 150 ft of sand, then the sonar jumps up to 40 ft, we know we're *probably* in the area. I have a Lowrance GPS/Depth finder combo unit, and in split screen mode you can watch your track and the depth at the same time. The sonar works decent at even fairly fast speeds, so it's not like you need to idle around for an hour looking for the structure/wreck.

Also, if there's a seafloor mapping project of the area (here is one of CA), see if you can double check the data. They're often listed with lat/long coordinates. Then see if they match your unverified numbers.

 

[Paleface]

Thanks All! At least I'm not the only one.

Lowviz- I might owe you a doughnut.