Totnes Sub Aqua Club

Dive Planning and Management

Sennen Cove

Dive Planning and Dive Management
A successful and enjoyable dive is a planned dive. Planning means arranging things in advance – and that is what you should do. Leaving things to the last minute invites problems. Planning requires time; at the last minute, there is none left. Dive planning starts by asking questions concerning the following subject areas:
All can be planned well in advance, even months ahead. Details can be sorted out in the weeks leading up to the event and finalised on the day. These notes are intended to provide a guide to the planning process.


Why Dive?
Objectives should be defined: is it to be a wreck dive, a scientific project, a search, a night dive, a training dive, or just an enjoyable day at the coast where Members’ interests can be fulfilled. Members enjoy the day more and are likely to be more enthusiastic if they know what they can and will be able to do.
Once the objectives are defined, the Dive Manager can plan the event and choose the site conditions that suit their successful achievement.


The Dive Manager
Which comes first – the dive objective or the Dive Manager? It may well be that someone wants to do a particular dive and has volunteered to manage it. However, if not, the Diving Officer (DO) could decide on the objectives, and then appoint a Dive Manager. Alternatively, the DO could appoint the Dive Manager and ask them to set dive objectives, choose the site and date and organise the dive.
All Branch Dives must be managed. The skills and experience required for this demanding, but important task is integrated into BSAC Sports Diver, Dive Leader and Advanced Diver training. However, for divers who qualified prior to September 2002 these skills were not taught until Advanced Diver.
At the time of writing:
Dive management is not necessarily taught as part of “equivalent” qualifications from other dive agencies and the DO will assess, on a case by case basis, whether additional training is required to allow such members to manage branch dives. Where a member wishes to manage a dive that they are not qualified to run, the DO will appoint a suitably experienced member to mentor them and to take overall responsibility for the dive.
The Dive Manager, or possibly the DO, should appoint, or invite, suitably experienced Members, including trainee Advanced Divers and Dive Leaders, to serve as Deputy Dive Managers. These appointments should be made well in advance. This gives the Manager much more chance to succeed than if appointed at the last minute.
The Dive Manager ideally needs to be well known within the club, respected as a diver, tactful and must also be able to exert authority if necessary. The DO should avoid “press-ganged” Managers – their lack of interest can result in a poorly organised dive!
The appointed Dive Manager is in charge. He or she can only be over-ruled by the DO and not by other senior Members unless they feel that the safety of the boat or divers is at imminent risk. The Dive Manager may exclude Members from the dive as appropriate, if it is felt that they do not have the necessary skills, experience or qualifications for the planned dive.


Deputy Dive Managers
Dive Managers may choose to delegate various duties to Deputy Managers – usually members requiring this experience for the Dive Leader or Advanced Diver qualification. Deputy Managers may be given responsibility for specific aspects of the dive – Boats, Equipment, Safety, Records, etc.
Depending on the nature of the expedition, the Dive Manager may wish to hold planning meetings with his Deputies both in advance and shortly before each event. These meetings can be used to go through plans in detail and agree the allocation of jobs to be done, to set timetables for completion of tasks, to chase up or finalise details and to allocate dive leaders etc.


Who Will Be Diving?
near the James Eagan Layne
It is the Dive Manager’s job to provide the sort of diving, training and assessments which members want, provided this does not compromise the underlying objective of the dive(s). The Dive Manager needs to know the present grades, training and assessment requirements of members; their interests, etc. so that he can choose the most suitable dive site and arrange dives so everyone is catered for and goes home happy. A tall order!!
The Dive Manager should always aim to establish who will take part in the dive in advance, by means of the club notice board and weekly email, although there will always be others who call-in at the last minute, or even turn up on the day on expeditions, but if members let you know in advance, it is easier to plan the dives they want.


What will they want to do?
Announce dive details and objectives at Branch Meetings and via the weekly email. Use Branch Notice board on which Members list their intention to take part, their grade, interests, training needs etc., or delegate someone to draw up a list.
Consider the following ideas when planning a Branch dive where various interests are to be met:
It may not be possible to meet every need if suitable support is not available. Tact is required when breaking news to an eager Ocean Diver – try to provide an alternative interesting activity.


When, Where, and How to Dive
Sennen Cove
When and where to dive are best considered at the same time because they are so interrelated. The questions are best answered by study of a calendar and Tide Tables. The best diving conditions are found at neap tides, unless you’re planning a drift dive!
Ideally, the chosen site should provide diving to meet all interests: new divers, trainees, experienced divers, and even non-divers.
Consider suitability and accessibility:
Consider how diving is to be conducted:


Sources of Information
Seek local knowledge – if diving in an unfamiliar area speak to local Branches, schools, local dive shops, tourist information offices, Regional Coach, local coastguard in advance or on the day. If the event you are planning is a large expedition, it may be worth visiting the site in advance with a small reconnaissance party to fact find.
On site, visit the Harbour Master and/or Coastguard to discuss availability or access to emergency services, proximity of recompression facilities and means of summoning help. If permission is needed to dive or gain access to a site, obtain it in advance. Phone the site or local contacts for information and booking procedures. Don’t leave vital matters to the day. Also check for local events that could affect your plans, such as sailing regattas.
Weather – watch trends in the newspaper, TV weather and web site links. Listen to Shipping Forecasts. Phone the Coastguard at the site before leaving home for a report on the present weather conditions. If they are bad, use the alternative dive plan. The scope of the alternative plan may not be so exciting, but the day will not be wasted.


Material Requirements

The Humber

Once numbers and interests are known and the site and date chosen, what equipment needs to be checked out or provided? Consider the following:
Diving Equipment: Members are responsible for their own. Remind them in advance to check if special items are needed. For example, a good torch (and a back-up!) for a night dive. If Branch equipment is to be provided a Member needs to be responsible for bringing it to the site. Remember the equipment needs to be returned in time for the next training session.
Ropes, weights, buoys etc. if needed for shot lines. Gas – check on availability and business hours of filling stations, both for air fills and for mixed gases for those members who use them. Is a local dive shop open in case of equipment emergency?
Boats: Are the Branch boats available? Will other boats provided by Members be available? Are all boats correctly equipped and serviceable? Will large boats have to be chartered? Discuss with the skipper the range of vessel and sites he can get to. Provisionally plan and agree with charter boat skipper which sites are to be dived. Liaise with Branch Equipment Officer. Delegate transport of boats to and from site, fuelling, checking to a Deputy Manager. Appoint boathandlers for the day.
Transport and Accommodation: Does anyone need transport to the site? Arrange lifts, meeting places etc. If overnight stops are involved, find out about available accommodation - hotels, boarding, camping and advise Members. Do they book or does the Manager make bookings for them? Give plenty of time and advance notice to avoid disappointment.


Announce Final Plans
Hold a final planning meeting to check with those who have been delegated to do things that they have been done or will be done in time. Chase up as necessary.
Announce final plans at Branch Meetings, on the club Noticeboard, or by email. Get a final list of names and interests so that dive groups can be made up and dive leaders chosen as necessary. Issue an information sheet and map/timetable to all those who intend to dive.
Make final confirmation of bookings i.e. charter boat. Watch weather and trends. Remind Members that the charter boat leaves at a pre-arranged time – may be forced to do so by tides. Tell everyone to be there early or risk missing the boat.
Set up a ‘check in’ procedure for the evening before so that Members can find out if all is “go” or about last minute changes to plans. Inform DO of proposed plan.
On the evening before get a weather check from the Shipping Forecast, the Coastguard or from Internet forecasts. If arranged, receive and answer calls from Members to confirm go, nogo or alternative arrangements and exactly where to rendezvous on the way to the dive site. Advise DO of any changes to agreed plan.
Before setting-out on the dive, check that the assumptions made in the Risk Assessment are still valid. The Dive Manager should be prepared to put any contingency plans into place at any point during the dive.
Finally, either on arriving at the dive site or just beforehand, the Dive Manager, or the Deputy Dive Manager if the Dive Manager is on shore or in another boat should give a short briefing to all divers. This briefing should summarise the dive plan and should point out any safety issues or relevant risk assessments that the conditions suggest.
After the dive make sure that everyone is safely accounted for and that all details of the dives have been recorded and the dives paid for, that the towers get away in a timely manner and that they have sufficient help at the boatshed to enable the boats to be washed down and put away safely (where branch boats are used) and advise the DO of any incidents and both the DO and EO of any equipment failures.
The following week, or as soon as possible after the dive, hand the completed dive log and any monies to the Treasurer who will then pass it on to the DO



Marshalling dives where different breathing gas mixes are used.
The Branch now permits the use of Nitrox and Trimix by appropriately qualified members on dives. Where some members choose to use breathing mixes other than air, the Dive Manager should have a clear understanding of the implications of using the proposed gas mix. Ideally, the Dive Manager should hold the appropriate level of Nitrox or Trimix Diver qualification him or herself - or appoint a Deputy Manager who does.


The Nitrox diver must advise the Manager of the percentage oxygen mix being used and its maximum operating depth limit. The maximum operating depth limit for Nitrox 27 is 42m: for Nitrox 32 it is 35m: and for Nitrox 36 it is 30m. These depth limits for Nitrox 32 and 36 are for no-stop dives only. If decompression stops are to be carried out in any sequence of dives, the maximum depth must be reduced to within the 1.4 bar P02 limit (see Nitrox MOD Chart below).
Generally, for all gas mixes, the P02 for any given depth should not exceed 1.4 bar absolute (but see decompression note at end of trimix section). To work out the P02 of any given mix, multiply the oxygen percentage of the mix at the surface by the absolute pressure at the target depth.
For example:
The process of determining safe P02 is simplified by using a P02 Look-Up Chart.
When recording dive details for Nitrox divers, the Dive Manager needs four extra pieces of information:
The BSAC '88 Nitrox Tables give easy look-up access to decompression information for Nitrox 27, 32 and 36. Alternatively, the divers may carry out decompression as if they had been diving on air and not Nitrox, thus giving themselves an additional safety margin. They may also use Nitrox or air dive computers. The Dive Manager needs to know which of these methods is to be used, and must be satisfied that the divers have calculated and planned their dive safely - and that they hold the appropriate Nitrox Diver qualification!
It is the responsibility of the Nitrox diver to have analysed his gas and to know what mix he is diving with.
Depth limits are critical when using Nitrox and site selection needs to be undertaken with care and some exactitude. A miscalculation by a few metres in depths of 30m+ could mean that divers who have provided themselves only with Nitrox as a breathing gas may have to abort their dive - or not dive at all.
When working with mixed groups of divers, the Dive Manager must consider the following:


The terminology “mixed gas” can encompass many types of gases a diver could breathe during a dive. However, it is generally accepted that the main gas used is Trimix. Trimix contains oxygen, helium and nitrogen in various percentages. The amount of oxygen in the mix is reduced the deeper the dive. This is to reduce the effects of high partial pressures of oxygen and to ensure the diver does not suffer from oxygen toxicity. The nitrogen percentage is also lowered to reduce the effect of nitrogen narcosis. Once the percentages of the oxygen and nitrogen have been calculated the balance gas added is helium.
When working with mixed groups of divers, the Dive Manager must consider the following:
Dive planning Trimix dive plans of depth and time should take into consideration:
A safety back up plan for all aspects of the dive in case of an emergency, which may include:
The Dive Manager must know and document:
All gases must be analysed prior to the dive and all cylinders must be clearly marked with their oxygen and helium percentages and MOD (Maximum Operating Depth). The BSAC recommend a suitable Equivalent Narcotic Depth (END) with regard to the dive conditions and a personal narcotic tolerance. The BSAC recommendation is not to exceed 40 metres. Most Trimix divers in Northern European waters aim for a 30 metre END. The partial pressures of oxygen (P02) should not exceed 1.4 bar.
When mixed gases and nitrox are being used the partial pressure of oxygen (PO2) should not exceed 1.4 bar for each mix used for either travel (descent and ascent) or bottom phases. For divers with additional appropriate qualifications a maximum partial pressure of oxygen for decompression of 1.6 bar is recommended.