Diver Storytime - Qualified Diver?

[Storker]

I'm used to knowing the hazards I'm supposed to watch for, I'm used to some kind of visual reference (called a MAP)... and in scuba, you get hardly any of that, at least in most locations.

Well, yeah, but...

I don't think it's at all realistic to wish for maps of every - or even many - divesites. Remember how maps are made, with aerial photography. You can't realistically do that underwater, 'cause viz is, at its best, some tens of meters, not hundreds. So we're back to making hand-drawn maps like they did before aerial photography was invented. And those weren't the best, at least not before they developed those nifty instruments for land measurements. Now, those instruments depend on line of sight.

Viz underwater is only in the tens, not hundreds of meters, so you'll have to cover the area very thoroughly to have any idea of the relative locations of structures, and cumulative deviation becomes a problem. And then there's often current as well. We don't have the tools to measure distances longer than a few tens of meters - and sometimes, in some waters, single-digit meters - underwater. A compass works underwater, but you can't take a bearing on the wall or the rock pillar just some 20 meters away, because it's outside the viz limit.

Even modern marine maps are rather approximate when it comes to mapping detailed structures underwater, and those maps are made with the aid of modern technology like sonar and GPS. Expecting maps detailed enough to use when diving would be like expecting to do detailed orienteering when your tools realistically can only produce topographic maps on the scale of 1:200 000 or smaller.

Besides, it's fun to be able to dive the same site several times and find new stuff every time And at least in this part of the world, you can find hand-drawn map sketches of some of the more popular sites if you know where to look and who to ask.

 

[TSandM]

One of our local charter captains (Don Coleman of Pac Adventures) gives a dive briefing to die for . . . By the time he is done describing what you are going to see, you have a 3D picture of the site, and it unfolds exactly as briefed. I love coming upon a ledge and knowing that I should have a careful look at the left end of it for a wolf eel den! It doesn't take away any of the adventure of the dive, to be sure that I know where I am during it.

Captain Jim of the Escapade in Monterey uses fabulous bathymetry images of the sites, to do the same thing. On the MV Tala in the Red Sea, we had 3D
models of the sites and wrecks, that could be turned around and looked at from different angles. Part of my enjoyment of the Thistlegorm was being able to recognize what I was looking at.

Different strokes, I guess; the more data I have beforehand, the more comfortable I feel. There are always plenty of surprises on a dive, anyway.

 

[DukeAMO]

There are dive slates printed with maps of some of the more popular wrecks off of NC. They're very nice. I'm a fan of maps, but only if I can take them with me.