This section contains details for Regular Branch Diving, i.e. one day events along the Sussex Coast. Details of procedures for more distant sites, and for expeditions, will be published in due course.

Regular Branch Diving

All the resources that you require are the Dive Marshal’s kit, either in paper form, or online. We have attempted to place as much of the Dive Marshal’s Kit as possible onto the Branch Web Site, so you should be able to undertake most, if not all  of the steps below, even if someone else has the physical kit at the time.

Because of space requirements, much of the Dive Marshal resources are kept on the Members-only web site. This causes one or two technical problems, which we will get around by opening links to these resources in another window. As long as you leave that window open, you won't have to keep logging-on!

1 - Pre-planning

All you need to plan at this stage is a date that you want to go diving, and somewhere to dive.

You may wish to consult the Diving Officer on your ideas of what may be an interesting dive and ask for support when needed to cover diver training or dives involving wreck surveys etc.

You probably already have a date in mind, but if not, then you may wish to choose one that has a low tidal range in order to minimise currents. Look at the Tidal Range Plot for the year (at the start of the Tides section in the DM Kit) and select a day than has a low tidal range if possible.

You also need to decide on a dive site, and a launch site that is near to it. When selecting your launch site then consider

  • car parking facilities
  • launching point for the boat
  • local bye-laws or council orders
  • harbour master’s rules
  • toilets and preferably refreshments
  • distance from home base
  • alternative interests for families if attending.

Please also consider where the Club is planning on diving within the two weeks before and after your dive (look at the Diving Calendar on this site). It is nice to have a varied diving schedule, and avoid going to the same places time after time.

2 As early as possible

Having set a date for your dive, and decided on a potential dive site and location ….

2.1  Advertise

Your dive needs to be properly advertised, and members made aware of what, where, when, how much, etc.

If you are arranging the dive at short notice, there may not be time for the above, so instead you should send an email to, and tell everyone about your dive.

2.2  Start Planning

As you work out the details of your plan, write them down on the Dive Planning Sheet.

Start the sheet by writing in the date and location of the day.

Pick a suitable and accessible launch site / harbour for your chosen dive site

There may be a choice open to you, especially if the site is about the same distance from two or more harbours.

Write in the harbour that you will be using.

Obtain the Lat/Long for the harbour entrance (your cox will want to know where to come back to!). Details for common launching sites along the Sussex/Kent coast can be found at . While you are there, you can write in the Mean Spring Range and Mean Neap Range at the same time.

Work out the tides for the day.

Refer to the Shoreham Tide Tables contained in the DM Kit (and the Notes that go with them) or an Almanac, and obtain the relevant details for the day. Remember to add the one hour in the summer months. Copy them onto your plan.

There are also links to EasyTide from the Regional Web Site, but be warned that this only works for up to seven days ahead. See

Do a few calculations.

These will come in useful later. Calculate the Tidal Range by subtracting the height of the low water from the height of the adjacent high water on either side of the time you want to dive.

While you are there, calculate the Range Percent using the following formula. This may come in useful later if you want to calculate slacks precisely. If you don’t do this step then that’s ok.

     Range % = (Tidal Range)-(Mean Neap Range) / (Mean Spring Range)-(Mean Neap Range)

This will give you an idea of how strong the currents are going to be – 100% represents mean spring currents, and 0% represents mean neap currents.

Work out the slacks for the day, and write them in.

You can use the rough figures for slack contained (sometimes) on the right of the Shoreham Tide Tables in the DM Kit.

Alternately, you can find the nearest Tidal Diamond to your dive site (write the chart number and diamond letter onto your worksheet), and use the Tidal Diamond Plots in the DM Kit to work out the slack more accurately. Please see the following web page for further details on how these are worked out:

Remember that the diamonds probably refer to a different port to the one that you will be using, so you may have to calculate the tides for that port as well at this point. Enter these details into the “Ref Port” section of your planning sheet.

If you feel that you need to work out precise slacks for the day, then you will need to use the following two spreadsheets. Save them onto your computer, rather than accessing them directly from the website. The second one contains full instructions how to do this.

Assess the available windows for launching and diving

Many harbours may dry out to the point where you cannot launch or retrieve your boat. Newhaven needs at least 2.0m over Chart Datum, while others, such as Littlehampton have a bar at the river entrance which “dries” to about 1 metre above Chart Datum, and represents a dangerous obstacle around low water, again requiring at least 2.0m over Chart Datum. Shoreham has a lock system which only opens at certain times.

If you are affected by either of these, then carefully calculate when you can launch / leave the harbour, and make a contingency plan in case you return late and cannot get your boat out!

Obtain GPS co-ordinates for the dive sites.

Some of the more popular wreck sites on the South Coast are listed on the Wreck page of the Regional Web Site at .

Other sources will include Dive Sussex, but beware that most of the co-ordinates in that book (and other similar ones) are in OSGB36 format, and in Degrees, Minutes and Seconds. If you need to convert these, use the calculator at

The more sets of co-ordinates that you can get for a particular wreck the better. It is much easier for the cox'n to find a wreck within an area than to precisely hit a point which might be at one end.

Work out an achievable timetable for the day

This may be possibly the hardest task to do, as you’ve got to second guess how efficient your divers are going to be on the day.

It is best to work back from the middle, and to do this, you need to know

  • when your period of slack water is going to be,
  • how long it is realistically going to last,
  • whether you are diving in one wave or two

Here are two examples, assuming that our slack water is at 13:00, and out divers will be diving for a total of 30 minutes.

Example 1: One wave.

12:15 15 mins Arrive at site, locate wreck, drop shot
12:30 15 mins Divers kit up
12:45 30 mins Divers in water
13:00   Slack – middle of dive
13:15 15 mins Divers surface, start de-kitting
13:30 10 mins Retrieve shot
13:40   Leave site

Example 2: Two waves.

11:50 15 mins Arrive at site, locate wreck, drop shot
12:05 15 mins Wave 1 kit up
12:20 30 mins Wave 1 in water
12:50 10 mins Wave 1 surface, start de-kitting
13:00 10 mins Slack – middle of dive
    Wave 2 kit up
13:10 30 mins Wave 2 in water
13:40 15 mins Wave 2 surface, start de-kitting
13:55 10 mins Retrieve shot
14:05   Leave site

By starting in the middle like this, you can now work backwards and forwards through the day.

Allow sensible amounts of time, an hour to prepare the boat at the start and end of the day, and remember that a lot of time will be spend motoring at slow speed in the harbour before you get out into open water.

You should now have a good outline plan of your day, and a sensible set of timings, so write it all down on the Timetable Planning Sheet.

Plan the second dive

It takes very little more time and effort to give your divers a second dive, (usually some sort of drift dive in our waters), so create a plan that will make this happen.

You may also get circumstances where some more junior divers cannot take part in your main dive, and you must provide a good opportunity for them to get wet during the day.

On occasions this may not be possible due to launch and recovery windows, but careful planning can help. Do not think that a “second dive” must happen after the “first one”. If you have a mid-afternoon slack, then organise the “second dive” for the morning, putting in your inexperienced divers with their instructors. Obviously the latter will not be able to dive in the afternoon, but may be happy to cox the boat for you. Make it happen!

Prepare your backup plan.

A backup plan is needed in case things happen, or go wrong, and your original plan cannot be successfully or safely executed. There should be no need to abandon a days diving just because you hadn’t prepared a backup plan. The sorts of things that you specifically need to plan for are:

  1. You can’t find the wreck you were looking for –

    Have reliable, trusted, and tested coordinates for a backup wreck, not too far away from your original site.

  2. The weather is too rough for your dive site –

    Have coordinates for a backup, more sheltered dive site.

  3. The weather is too rough to go to sea from your harbour –

    Plan to take your diving party to an inland dive site instead.

3 - In the week before

Listen to the weather forecasts each day and watch the weather.

As your dive draws closer, you can start to get more and more accurate weather forecasts. See the links to weather resources on the Regional website at

Collect details of members of your dive party from the original notice or however.

Complete the Dive Planning Sheet – Personnel with the names.

Refer to the pages in the DM Kit to determine their grades, and to find out towers, cox’ns, and rescue skills. Make notes about all these on your Personnel Planning Sheet. You may find it helpful later to fill out the form with the most experienced people at the top, and the least experienced at the bottom.

Review the plan in light of the people and the places involved. Can everyone participate in the dive, or are there some who are too inexperienced for the dive you have planned. If so, then you may need to have them dive only on the second dive of the day.

Allow for any training requirements you may be asked to include, but don’t necessarily wait for them to come to you and ask. If you have some inexperienced divers, then it is highly likely that you can arrange some relevant training for them during the day. Make it happen!

Decide pairings based on experience levels and interests. There is plenty of BSAC guidance about pairing divers, especially if you are faced with “techies” using Nitrox, Mixed Gases, or Rebreathers.

In the absence of any other criteria, it is safe to pair the most experienced with the least experienced, and work through your list that way until you reach the middle. Try to avoid threesomes wherever possible, but if they prove to be required, make sure that they consist of two more experienced divers and one less experienced diver, rather than the other way round.

Organise the divers

Make sure everyone knows where to meet, and when. Arrange maps for everyone if necessary.

Organise the boat preparation

Ensure all equipment is present and correct. See Tornado Preparation Checklists

Select members of your dive party to tow the boats.

Tell them if they have to fill the boat(s) with fuel on their way to the launch site. Ensure that there is enough two-stroke oil available for what you have planned for the day.

Decide who coxes the boats and who goes in which boat.

Complete the Dive Waves Planning Form with these details

Check everyone is properly equipped and will have enough cylinders and air for the day.

Prepare marshalling slates, pencils and erasers for each boat

Prepare a formal Voyage Plan.

Complete a Voyage Planning Sheet for each boat that you plan to be used, and for each trip out that it is going to make. Make sure that you include details such as any dangers, and harbour speed limits and signals.

Review your plan in light of the above.

Is it still achievable? Is it within the experience and capability of all the divers who will be attending? Is it within the range and capability of the boats given the number of people attending (with eight divers and their kit, the Tornado is capable of about 20 nautical miles on a full tank if driven sensibly). Re-plan your day if necessary.

4 - On the day before

Get an accurate tidal plot for the next day

Get one for both your harbour and the reference port for your tidal diamonds. See

Get the Shipping Forecast and Inshore Waters Forecast for the day ahead.

Decide whether the dive goes ahead or whether you have to revert to your backup plan. Makes sure that all your divers know what will be happening (get them to telephone you between 18:00 and 19:00 on the day before the dive).

5 - On the day

5.1  At the start of the day

  • Get there first
  • Verify that the boats are topped up with fuel and oil
  • Give a thorough briefing to your diving party, but don’t tell them more than they need to know. A blow by blow account of the day’s timetable will just bore everybody. Tell them:
  • necessary details about the site, including facilities
  • when they must be kitted and ready by
  • who they will be diving with, and when
  • which boat they will be in, and who the cox’n is
  • how much the day is going to cost, and when you will be collecting it.
  • when you expect to be back on shore
  • how long any breaks, eg for lunch, will be
  • when you expect the day to finish.
  • Appoint Deputy Marshals to supervise boat preparation and launching. Select a member of your party to be responsible for the Dive Records for the day.
  • Separately, brief cox'ns on passage plan, dangers, and harbour speed limits and signals. Provide them with the marshalling slates, pencils and erasers for each boat. Have them sign the Voyage Planning Sheet for their boat.
  • Arrange for payment of launch fees

5.2  During the day

  • Keep an eye on the weather and sea conditions.
  • Ensure someone on shore has details of your plans, including return time, and instructions about what to do if you do not return within a reasonable time.

5.3  At the end of the day

  • Ensure that the person on shore who has details of your plans knows that you are back.
  • Check everybody is accounted for, and give a debriefing to your party
  • Collect payments from divers.
  • Ensure nothing is left on site, and be last to leave.

5.4  Back at the Club Hut

6 - As soon after the dive as possible

  • Hand on the Dive Marshal Kit to the next Marshal
  • Complete a Dive Record Sheet and return it to the Diving Officer
  • Complete a Dive Account Sheet and return it to the Treasurer

Just in case

Although we all hope that it will never happen, the Incident Report Form appears below if needed.

This should be completed as fully as possible. Please actively involve the Diving Officer in the completion of this form, as it is his/her responsibility to forward it on to BSAC HQ.