Dive Planning and Management

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:

• Why – dive? What are the objectives
• Who – is to be in charge? – Who can participate?
• Where – will it take place?
• When – will it take place?
• What – is required? Boats, equipment, accommodation, etc.
• How – is it to be carried out? Dive plans, diving rota, etc.

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 D.O. could decide on the objectives, then appoint a Dive Manager. Alternatively, the D.O. could appoint the Dive Manager and ask him 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 a:

• Sports Diver shall be trained to be an Assistant Dive Manager
• Dive Leader shall be capable of Dive Managing known sites
• Advanced Diver shall be able to manage and supervise diving to explore unfamiliar locations.

In addition to the above, it is a Totnes club rule that all Branch diving activities will be in the charge of a Member who is an Advanced Diver (or above). It is vital that someone is in charge to avoid conflicting instructions and confusion.

The Dive Manager, or possibly the D.O,. 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 D.O. should avoid “press-ganged” Managers – their lack of interest can result in a poorly organised dive!

The appointed Dive Manager is in charge. He can only be over-ruled by the D. O. who appointed him and not by other senior Members. 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 Dive Leaders 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?

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?

• Members will want to enjoy themselves
• Do their own thing
• Ocean Divers will want training dives and early experience dives
• Experienced divers will want more advanced diving

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:

• Experienced divers do an advanced dive in the morning so they can be available to help with experience or training dives later in the day.
• Run “experienced divers only” dives or training only dives.
• Team up divers who share similar interests.
• Availability of suitable instructors, dive leaders, boatmen etc.

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

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!

Consider:

• Availability of advanced divers, dive leaders, members
• Holiday Seasons
• Availability of boats – book charter boats early
• Weather – always unpredictable, but in some seasons more predictable than others.
• Make alternative dive site plans
• Are you going to dive both days of a weekend?

Ideally, the chosen site should provide diving to meet all interests: new divers, trainees, experienced divers, and even non-divers.

Consider suitability and accessibility:

• Distance from Home – can Members come out for a day or will an overnight stay be required?
• Accommodation
• Adequate car parking
• Good beach for children
• Shops or attractions for non-divers
• Safe entry and exit points
• Safe boat launching and recovery at all states of the tide
• Suitable water/diving conditions for planned dives and divers
• Availability of gas fills
• Boat hire
• Minimum disruption to locals and fellow beach users
• Likely crowding at holiday times
• Overall safety of the site – remote sites require greater provisions for safety

Consider how diving is to be conducted:

• Shore or boat dives
• Number of divers – diving by rota or in waves?
• Decompression requirements
• Air Requirements
• Use of a Dive Planning Slate
• Prepare Risk Assessment(s)

Sources of Information

Consult:

• The Dive Manager’s Folder – did you know we had one ? (the D.O keeps it)
• The Branch, BSAC, SAA and Club websites
• Tide Tables to determine the best day and time of day for dives
• Charts to determine the times of slack water, rates and directions of flow, depths of water on site
• Use local tidal predictions
• Decompression tables
• OS Maps, local guides
• Diving books
• Wreck Registers
• Local Knowledge

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

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 D.O. 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 D.O. 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 D.O. of any incidents and both the D.O and E.O. 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 D.O.

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.

Nitrox

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. 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:

• Divers wish to use Nitrox 38 for a dive to 20m. Is this a safe mix?
• Nitrox 38 means 38% oxygen. Absolute pressure at 20m is 3 bars.
• Therefore, the P02 in this mix is: 0.38 bar x 3 bars = 1. 14 bar - safely within the 1.4 bar limit.

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 three extra pieces of information:

• Oxygen percentage of mix.
• Maximum operating depth.
• Means of monitoring decompression.

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:

• Air divers should be paired according to qualifications and experience.
• Nitrox divers should be paired according to qualifications and experience - and similar mixes.
• If pairing Nitrox divers with air divers, the Dive Manager must consider the safest dive profile and decompression for both divers. The pair must therefore observe the maximum operating depth of the Nitrox diver and limit their dive time to the maximum dive time of the air diver. These considerations allow the greatest safety margin for both divers.

Trimix

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:

• 1.Dives within 50 metres could include air and Trimix divers on the same dive. It is recommended that the Dive Manager should:
  • Pair air divers planning the same dive and decompression schedule
  • Pair Trimix divers planning the same dive and decompression schedule
  • .If pairing air and Trimix divers together, both divers must carry out the same decompression schedule to ensure they remain together at all times. This means both divers follow the most conservative schedule, likely to be that of the Trimix diver
• 2.Dives in excess of 50 metres should only be performed by Trimix divers
• 3.The BSAC recommend a Trimix diving depth limit of 80 metres

Dive planning Trimix dive plans of depth and time should take into consideration:

• The Trimix divers experience
• The divers current fitness to dive
• A suitable dive platform and experienced skipper

A safety back up plan for all aspects of the dive in case of an emergency, which may include:

• Written decompression schedules for longer bottom time than planned
• Written decompression schedules if diver was unable to use travel or decompression gases in case of a gas loss or equipment failure
• Spare decompression gas available to the diver in case of a gas loss or equipment failure
• How the divers would access the spare gas in an emergency (spare cylinders on decompression line or cylinders lowered to divers from diving platform)

The Dive Manager must know and document:

• Divers gas mixes for bottom, travel and decompression
• Divers Maximum Operating Depth (MOD)
• Divers cylinder sizes for all gases
• Divers planned decompression schedule
• Divers planned decompression technique
• Divers back up plan in case of an emergency
• The Dive Manager should complete a full dive log

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.