Dive Marshalling carries with it a great deal of responsibility and it has its own rewards.
Most of the summary details, the plan, maps, phone numbers etc., would have been given out at the planning meeting. The aim now is implement the plan and ensure everybody has a safe and enjoyable time diving.
It is extremely difficult for one person to manage all aspects of the dive, it is much better to delegate responsibilities to other competent members; this not only develops their skills but also gives you some thinking and planning time. Don't fall into the 'it's quicker for me to do it' trap, as the other divers will never learn it.
Delegate the following:
- Boat Marshall - responsible for the safety and return of the RIB.
- Equipment Marshall - responsible for equipment such as Oxygen, first aid etc.
- Training Marshall - responsible for training issues.
- Record Keeping - responsible for ensuring dive slates are completed.
- Other responsibilities may include; getting cylinders refilled, organising and collecting lunches.
Estimate journey and dive timings
Use your best judgment to estimate journey times, and allow extra time if you are towing the boat or traveling at peak times e.g., rush hour, Friday night, Sunday evening etc. Computerised journey planners such as 'Autoroute' may help. The unthinkable always happens so allow plenty of time for these and other stops.
Allow at least an hour once at the slip or harbour to prepare the RIB, secure the trailer, kit up and launch it.
Estimating sea journeys is also very variable and depends on distance, the boat, number of divers, tides and the weather conditions. Ensure there is plenty of time to meet slack water. If you are locating the wreck leave plenty of time to find it and shot it which may take several attempts.
Ensure that the equipment marshal checks, tests and confirms the functionality of the oxygen and first aid equipment.
Arrange meeting points and times
Make sure everyone knows where and when to meet and emphasise the need to be on time. A good way to do this is by making it clear that if they are not there on time, they may miss out on the days diving.
Get a weather report
Get a weather report. Metfax is best but it is relatively expensive, try local papers and TV.
The most important safety factors are the sea state, directly related to the wind and tides, the sea swell and surface visibility. Collectively these indicate how well you can see the surfacing divers. Remember the BSAC limit is Force 4 and rough seas will often make people ill, agitated and less disciplined. There is also a greater risk of injury when divers are thrown around. Launching and recovery can also be hazardous.
Consider the following:
- If the wind is in the opposite direction to the current, waves will be far worse than if they are both running in the same direction.
- If the wind is coming off the land, the swell is normally far less than if the wind is coming in off the sea.
- There may be sheltered water in the lea of the land.
- Bear in mind it is not just what is happening at that moment that is relevant, perhaps more important is what is likely to happen over the next hour or two e.g., will the wind or tides lessen or strengthen? Will the wind or tide direction change for the better or not? An out bound journey may be smooth if traveling with the wind but the inbound journey could be very different.
- Fog can be very risky as divers easy to lose and navigation is harder.
- Cold weather is very bad for poorly protected divers, especially after cold water dives and/or long high speed runs back to shore as these all increases the risk of hypothermia. Clearly, the risks of hypothermia increase markedly with leaking suits.
Consider the above and ensure that safety is not compromised, nobody likes canceling dives but if the conditions are unsuitable for the skill range of the divers cancel it and look for safe alternatives. Better safe than sorry.
Decide whether to use SMB's
As a general rule, use them wherever you can, if entanglement etc is an issue, get the divers to deploy a delayed SMB whenever they drift or swim off a wreck or a predefined area. Tracking bubbles is perilous.
Buddy-pair the divers
Buddy the divers with safety as the main criteria, if any divers need looking after or inexperienced, buddy them with experienced divers. After the safety issues have been catered for, you can pair divers on various criteria such as:
- Using Tables or Computers.
- Twin sets and single cylinders.
- Similar air consumption.
- Similar intentions e.g., photography, wreckie's, nature lovers.
- Gas mixes - e.g., Nitrox, Trimix.
- Personalities - avoid mixing the unmixable.
- Comfort - some inexperienced divers might feel uncomfortable with divers unknown to them; check they are comfortable with their buddy.
- Couples, close relations (e.g., husband and wife, brothers etc). There has been much debate about this and there is an argument for not pairing couples or close family. This is based on the belief that, should an incident occur, one diver may take higher risks to save the other, than they might ordinarily, and also they may suffer from higher levels of guilt should the worst happen. Dive Marshals will need to make up their own mind on this.
Morning dive briefing
Armed with above information it is good practice to have a dive brief. The aims are to ensure everyone understands what is required from them during the day and when. The key points to be discussed are as follows:
- Introduction and welcome.
- Timing is critical so be ready.
- Check if everyone's fit.
- Number and type of diving.
- Details of any training or other 'must do's'.
- Outline key responsibilities e.g., Marshal's, coxswain, equipment, records, air refills.
- Explain any known problems e.g., sounder nor working.
- Pairings - who will be diving with whom?
- Give weather report.
- Currents and slack water timings.
- Explain location of first aid equipment and oxygen equipment.
- SMB and DSMB Policy.
- Air refills - who, when, where.
- Explain toilet facilities.
- Location of keys.
- Mobile phones.
- Dive 1 - Explain: (and repeat for dives 2 & 3).
- Location, transits, bearings, maximum dive time
- Timings, maximum dive times, expected currents (speed and direction) slack water, sea state.
- Type of dive, wreck details, direction of wreck, position of shot.
- Particular dangers - e.g., entanglement, accidental penetration.
- Expected depth and visibility.
- Expected decompression stops.
- Equipment requirements, e.g., SMB's, compass, knives.
- Boat details.
- Launching - who, location and time.
- Boat recovery.
- Fuel management.
- Backup plan.
- Next meeting time and location.
Keep everything moving quickly
It is incredibly easy for time to tick away resulting in deadlines or dives being missed. It usually occurs because of something quite trivial like someone has forgotten a key, or a piece of vital equipment is in the wrong car etc. Where possible, build into the plan, time for these inevitable time wasters. Make sure everybody knows the key timings and locations.
Use tack and diplomacy
Nobody likes to be shouted at or made to feel foolish, being a dive marshal requires tact and patience. Stay calm and keep an eye on what is happening. If you see anyone dithering around or simply chatting, point them in the right direction by asking question e.g., "is your equipment ready for the boat"? rather than "get your equipment ready" or "will you give John a hand"? rather than "give John a hand".
Estimate the visibility from the boat
Once in deeper water, look down into the sea where the water shaded from reflections (e.g. close against side of boat). In the UK, the rule is the blacker the better. If the water looks green or milky, the visibility is likely to be poor. The colour of the white water can also give a clue.
In early summer particles of plankton can often be seen. Prolific fine plankton can degrade visibility substantially although you can sometimes get beneath the plankton.
Watch bubbles from props or the waves. Poor visibility makes the bubbles near the surface look green or brownish. The visibility is good if can see the deep bubbles and they just look darker rather than green or brown tinted. This often gives a useful guide to probable visibility on the dive, but beware that surface visibility not a guaranteed guide to visibility at depth. Crud and plankton blooms can form layers in water at any depth, so good surface visibility may yield to awful visibility at, say, 15m. Even if the visibility is poor at the surface, it can occasionally be good at the bottom; though will be darker than normal for the depth.
Brief the divers
Most of the general information would have been discussed in the dive brief, however remind the divers of the following:
- Possible hazards - e.g., poor visibility, unexpected drop-offs, wreck holds that may be entered accidentally, currents and slack window, netting, etc.
- The maximum dive time for diver to be on the surface, if required.
- Use of SMB's or when to deploy DSMB's for example, as soon as possible, when leaving site etc., and whether divers are expected to return to the shot for the ascent.
- Tidal direction and rate currently and what is expected to occur.
- The direction (if any) that divers should swim.
- Depth of water.
- Expected visibility.
- Location of the shot in relation to the wreck, e.g., Bows, amidships etc.
- The directions in which the wreck is lying i.e., the best direction to swim.
- If more than one boat is on site, agree a special pickup signal so the skipper can tell his divers from others.
- Ensure the divers know the diver recall signals and tell them to surface as soon as possible.
- Advise the divers that three strong pulls on the SMB means ascend.
- Remind divers of the dive site, what to look out for, what is interesting etc.
- Give everybody the option not to dive, if they don't feel up to it for any reason.
There are number of signs that could indicate problems ahead. Monitor the mood of divers and watch them kitting up. Look out for seasickness, as sufferers will be extra keen to get in the water and may skimp on buddy checks etc. Look out too for the 'know it alls' and the divers who have safety low on their priority list.
Make sure your records Marshal has everything they needs to accurately record all the information required on the dive slate. The dive marshal should ensure that whilst they are diving whoever returns to the boat first completes the details until the records Marshal can continue.
A debrief of the days diving can be a valuable learning tool for all concerned. Discuss:
- What went well?
- What went badly?
- Outline the lessons learnt.