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Divemaster Mapping Project

Drafting a clear and effective dive site map is an important skill that every dive master should possess.  The role of a dive leader demands knowledge of dive sites as well as the use of dive site maps when conducting a pre-dive briefing. This knowledge should include layout, distances, depths, entry and exit points as well as any possible currents and hazards. Safety is an important factor but having a map will allow divers to visit the best features of the site by marking where they are and what to look out for.  It is a PADI requirement, and also a large part of our Divemaster course.  Here are a few tips meant to assist you with making your own dive site map.

If a dive site is shallow enough, remember that you can do part of the mapping project while snorkelling it. This will help you keep oriented and get a better general overview of the dive site.  This, however, can only be done on days that visibility allows you to actually see the underwater detail.

On actual dive trips, one of the easiest ways to start mapping a dive site is to simply keep oriented while doing “fun dives”.  You can accomplish this by paying attention to your compass, knowing where you are in relation to the entry points, buoy lines, or whatever landmarks.  This way you are slowly adding detail to your own mental map of the site, filling in blanks with every dive trip.  Once you feel like you can draw a rough outline of a dive site from memory, you should do that, and then fill in the more precise info.

Getting the more precise detail is more tricky, as you need a better level of orientation.  You can achieve this by using a large slate, tape measure / reel, compass, depth gauge and fixed buoy in order to create an accurate picture of the underwater terrain.

Large slate: If possible use one with pre-printed grid markings.

Tape measure: purchase a 30m reel from local dive equipment shop

Compass: use a compass to draw intersecting distance arcs.

Secure buoy (or use pre-installed buoy lines): use as a central point from which everything is to be measured.

Once you have all your required equipment, you can start the survey following these steps:

(1) Start by drawing a quick sketch of the site from memory or your paper map onto a “working slate” which you take diving with you – it’s a good base from which to add known measurements and bearings and will help you set parameters. Also, note down some kick cycle to metre conversions (eg.: “10m — 13 k.c.”) to help with distance calculations, OR keep everything in kick cycles and convert at the end.

(2) Select a central point from which everything on the site will be measured (setting up a buoy will allow you to attach a reel to measure distance) – when doing this, make sure no marine life is damaged by the line (only a few dive sites will allow this).  If unable to use a line, follow your compass and count kick cycles.  Map out bearings and distances between landmarks. Including the bearing information between major landmarks will make your map that much more useful.

(3) From the central point swim using a U search pattern as it a good way of covering a large area.  Alternately, you can dive a series of complementary square patterns always starting in same point (say, bottom of buoy line), or an expanding square.  Whatever you do, try to move on a heading as precisely as possible, and note various features: rocks, corals, sponges, any permanent features.

(4) Note features as not-to-be missed areas of the dive as well as of any potential hazards. Note entry points for both boat and shore diving (if applicable).

(5) If drawing to scale you’ll need grid paper and rulers. This will highlight areas that may need to be surveyed if they don’t match up correctly.

(6) Note the depths to the bottom if known (make a note after every 5-10 meters or so) – this helps create contour lines on your final version.

(7) Add relevant topside features (beaches/sandbars, rocks, structures)

Here is a series of horrible doodles which explain the evolution of a dive site map, in this case, Koh Tao’s “Twins”.  Located between the Nangyuan Islands, to the west of the sandbar, The Twins are a great mapping project for beginners because they are relatively easy to keep oriented, shallow, and full of good features that can be included on a map.  The first version of the map is a very rough draft, indicating Koh Nangyuan Island, the sandbar, the rough outlines of each of the rock piles that Twins consist of, and a kick-cycle to metres conversion chart. Notice that North is also indicated (top of the map), as are thee buoylines.

Twins Map - Version 1
Twins Map – Version 1

This map, transferred onto a diving slate, will help you with the next phase, which is figuring out the bearings between different key landmarks.  While doing this, you should remember to note not only the compass bearings, but also distances between the landmarks (using kick cycles, then converting to metres), and also start putting in more detail, finer features of the divesite.

Twins Map - Version 2
Twins Map – Version 2

Once you have a good amount of detail, with bearings and distances between key landmarks, you could start doing a more detailed and methodical survey utilizing either a U-search pattern or a series of square patterns which will allow you to cover a greater area while staying oriented, and filling in all the finer details, including depth info, bottom composition, etc.

Twins Map - Version 3
Twins Map – Version 3

Then, when you feel like you have all the info and all the detail you need you can start transferring all of it onto a final (or something near it) version of the map.  Point out some interesting landmarks, coral life, sand patches, overhangs/swim-throughs, as well as surface/terrestrial landmarks.

Twins Map - Version 4
Twins Map – Version 4

[The above maps are HORRIBLE “drafts” to illustrate the concepts, but have virtually NO accuracy – I purposely do not give away the info so you have to go and gather your own. Please DO NOT copy these for your actual DM project submission.]

Additional points to remember when working in a map:

  • It is all about teamwork, so work as a team and don’t attempt to dominate the group.
  • Planning and preparation should take just as long as execution. Take your time prior to heading out for each in water session to ensure you don’t waste your time.  Do a proper briefing.
  • Don’t attempt to map an area that is too large in too much detail.  When mapping Koh Tao’s “Twins”, let’s focus on the eastern, shallow one.
  • Be realistic with the group’s goals for each session. This will keep morale up and keep you enthusiastic.
  • Don’t cheat and look up an existing map. You will learn nothing, and this cheat is easy to catch!
  • Don’t get stressed when things don’t go your way. There will be sessions that will not be as productive as you had anticipated. Bad currents, poor visibility, hug waves, etc.  Roll with the punches, re-asses and redevelop another plan. This is what the project is all about.
  • Bring and practice using the SMB during this project.
  • Don’t stop developing the map when you hand it in. Each time you go out to a dive site, you should be creating a map to improve your current base map. If you dive 10 times at every site in the area, you will have some pretty cool maps to use when you start working as a dive master.  Your customers will love you for it!
  • Most of all: HAVE FUN and enjoy the experience!