As we talk about public safety diving (PSD), we hear a lot about the divers and their training or the types of equipment divers need to get the job done safely. But tenders often get lost in the shuffle.

There are those who say you can take anyone off the street, hand them a tether line, and make them a tender. What do tenders do after all? They get divers items they might have forgotten or need and then they just hold the diver’s safety line and tell him when to change direction. They then bring the diver up every so often to check his air. It sounds very simple.

There are others who believe a confident, well-trained tender may be the most important person on the dive scene, especially as it pertains to the diver’s safety and search effectiveness. This article addresses two issues—the importance of tenders in general and the value of having dedicated tenders on the dive team.

Tenders function in several roles in relation to the diver, including director, assistant, and safety officer. Well-trained tenders help make sure divers are physically, mentally, and equipment ready to dive. They evaluate environmental conditions to determine what search patterns will be most effective. More importantly, they can ask and understand the two most critical safety questions:

1. What can go wrong on this operation?

2. If those things do go wrong, do we have hands-on practiced, proven contingency plans to get us both home at the end of the day?

Yes, command staff should be asking those questions, but the tenders are those on the front line who should be catching the environmental details and who are constantly and consistently evaluating the divers.


The tender needs to thoroughly understand the diver’s equipment, how it is assembled, and how it works. If something goes wrong, tenders need to know how to fix it or know when it needs to be replaced. In the case of simply switching tanks, for example, tenders need to know how to properly tighten or rethread the tank band cam buckle—metal, middle, bottom, top—a skill too many divers do not know how to perform.

While dressing their divers, tenders perform several tasks. They work alone or with the diver to assemble the dive equipment and check the assembled gear prior to the diver’s donning it. Tenders know where everything is on the dive trailer or truck, and well-trained and experienced tenders recognize problems and know how to fix many of them. They can evaluate air leaks or full face mask problems, swap out a broken fin strap, and manage a regulator freeze-up and might even know how to quickly patch a vulcanized rubber suit on the scene.

Tenders ensure that divers do not get overheated or worn out by getting dressed in a hurry or on a hot day. On cold days, tenders work to keep divers warm and help prevent equipment freeze-up problems. Divers and tenders perform a full gear check prior to entering the operations zone. They ensure that the pony and primary air are turned on, that the pony bottle or other support systems are fully functional, and that divers can effectively and reflexively reach all their equipment without looking. If not, the efficient tender will correct the problems.

Post-dressing, tenders can reaffirm basic signals and begin a basic overview of what the dive operation is about and how tenders and divers might interact. They check diver tether lines and perhaps electronic communication systems to ensure they work properly. When they don’t, experienced tenders will know how to fix them or whom to see to get that done. Tenders should understand the basics of troubleshooting equipment malfunctions.

Dry Suit vs. Wet Suit

Consider what tenders need to know and be capable of doing if the team dives in dry suits. They must know how to properly assist divers to dress in a dry suit vs. a wet suit. They also must do the following:

  • Ensure that the delicate neck and wrist seals are properly donned and are not too tight, cutting off circulation.
  • Immediately recognize the signs of carotid sinus reflex.
  • Ensure that the seals don’t leak and are sitting in the right position, especially in contaminated water.
  • Ensure that the inflator valve is in the correct 45° downward position for a rapid contingency disconnect and the hose is properly connected.
  • Determine if the deflate valve is set to the right position for the depth and temperature of the dive.
  • Determine if the skull cap is sitting properly under the hood and the face seal is correctly cut to prevent leaks and the chin section from slipping upward, sealing off the diver’s airway.
  • Determine if the diver needs ankle weights.
  • Determine if the gloves are properly donned to make a safe seal.
  • Determine if the diver effectively “burped” the suit.
  • Ensure that the diver’s weight system is loaded with the right amount of weight to keep the diver neutral to two pounds negatively buoyant, depending on the dive job and environment.

2 Tenders help the diver get to the water or boat and run the dive.

Divers are basically underwater rovers who are often blinded in black water; their tenders direct their movements and monitor their times, air pressures, search quality, and breathing rates.

Tenders ensure that all the needed equipment is in place and that the diver is belayed down a slope and up and over things that might be in the diver’s way.

Tenders do whatever is needed to keep the diver safe: make sure the divers are hydrated and kept cool or warm, as is appropriate for the conditions, using more effective procedures. For example, a well-trained tender would not dump water over dry suit divers on a hot day to cool them down. Instead, the tender would hold the neck seal slightly away from the neck while hitting the inflator valve.

If the diver-tender pair is the backup team, the backup tender coordinates with the primary tender to maintain a constant awareness of what the primary diver is doing and where the diver is in relationship to the dive operation.

Experienced tenders know the difference between moving and nonmoving water and how to properly tend their divers and orchestrate a rescue of their divers in possibly changing conditions. Tending, just like diving, has different levels of certification. One tending program does not make an expert in all types of operations. Every time divers take a training program, tenders should be right there with them. Tenders need to train at the same rate as divers. Examples of tender certifications include ice-diving operations, boat-based diving, overhead obstruction diving, moving water, hull/bridge searching, deep water, contaminated water, and surf operations.

Backup Tenders

Effective backup tenders continually maintain the record keeping for the primary team, to ensure that they are alert and totally aware of what is going on every minute of the dive in case the tender and backup diver are suddenly needed, and also to document the search effort. The backup tender produces an accurate map of every move the primary diver makes during the search. If the primary diver gives one foot of slack in the tether line, that will be documented.

If the search item is not found, backup tenders and their divers will be in the primary slot next. Consequently, they should be aware of any difficulties during the prior dives.

Well-trained tenders need to count divers’ breath rates (exhalations) every five minutes and know how to extrapolate that information with depth and individual diver surface air-consumption rates to calculate the air used by their black water divers, who cannot read their own gauges. Proper training helps tenders understand the importance of diver breathing rates and the rate of speed with which the diver is moving during the search.1 If, for example, the tender is not aware that a diver’s ascent rate was 120 feet per minute instead of the maximum acceptable two seconds per foot, the tender will not know that the diver needs to be evaluated post-dive for possible barotrauma and will not alert command or the safety officer that there is an issue that should be evaluated and monitored.

Tenders must have a thorough knowledge of the team’s safety standards and standard operating procedures and guidelines and how to apply them. They must have a basic idea of how deep their divers are based on the angle of the safety line and must continually read line markings to know and document their divers’ distance out.

Experienced tenders understand the importance of a taped and measured diver tether line. They know that putting loops in a line every so often is not going to give a repeatable distance; loops in the diver’s tether line will increase the chances of otherwise missed snags and the coefficient drag on the line and reduce the line’s free movement through the water.

Experienced tenders know when something is wrong often before the divers themselves know it. They know how to “read” or feel little movements in the diver’s tether line and can distinguish between movements that indicate that the diver’s line has just caught a snag or has just become free of one.

Experienced tenders can tend divers in heavy grass, on slopes, in heavy mud areas, and where there are a lot of submerged trees or other debris. They know how to safely and effectively tend a diver who has gone or needs to go under a pier or a dock. Tenders, like divers, need specific training and experience to perform submerged vehicle dives. They need to know how to work their divers around vehicles and when a tender-controlled search should be changed to a diver-controlled search with the backup diver acting as a tender down at the car.

Electronic communications can be a real asset to a search when used by competent tenders who understand that the more they talk, the more divers will lose search concentration and will more likely hold their breath while listening to their tender. If an experienced tender senses from the diver’s breathing or speaking that the diver is stressed, the tender will know what to say and how to say it to calm the diver.

Poor to Zero Visibility

Trained tenders guide their divers, ensuring that all areas are being methodically searched. They know when an area has been searched well or when it has been searched too quickly for the size of the search item and the environmental conditions.

Tenders set up turning points and properly work a search area and know how to create a profile map and work with ranges. They have many techniques to use to change or adapt the pattern as needed to help the divers get their job done as efficiently and safely as possible.

Since, as previously noted, divers often cannot read their pressure gauges, the tender should know how to figure out approximate air usage of the diver on a three- to five-minute basis according to diver exhaust bubbles and approximate depth and should know within a few hundred pounds per square inch how much gas the divers still have available at any point during the dive without having the divers surface.

Moving Water and Other Higher-Risk Environmental Conditions

Tenders need to know when and how to abort a dive based on changing conditions that can include currents, debris, and weather. Making these decisions requires an understanding of moving water and bottom compositions, the effects of temperatures, water quality, and much more.

They need to know the depth perimeters of the divers and teams to keep the divers out of depths beyond their capabilities. The same is true for all safety standards relating to environmental conditions.

Tenders need to be capable of running boat dives, including setting up the dive boat with hurricane anchoring and other procedures. A trained tender knows the average dive team cannot function safely from a shore-based operation in currents greater than a half a knot. In currents greater than a half a knot, the operation should be moved to platform- or boat-based operations.

As pertains to safety, tenders must maintain direct line access to their divers and realize how difficult it is to rescue a diver who is at an off angle to the current. They must know how to work current-based patterns, how to calculate how fast a current is moving, and if their team is trained and capable of diving in such conditions.


Tenders may be the most important people on a dive operation. If a diver finds the search item, that occurred in large part because of the tender. If a diver goes home at the end of a difficult dive, that is in large part because of good surface support.

The importance of having dedicated tenders is often overlooked and undervalued. Dedicated tenders serve strictly as shore support and do not dive. These team members are invaluable and are worth their weight in gold. If we had a choice of who was going to tend us on a dive, we would choose a dedicated tender over a diver-tender on almost every occasion.

In brief, dedicated tenders typically make better tenders than cross-trained individuals (“diver-tenders”). They save the department money and add a valuable level of safety and effectiveness to dive team operations. We will call the cross-trained members “diver-tenders.”

Our combined experience of more than 60 years working with rescue and recovery dive teams has shown that dedicated tenders typically follow safety standards to the letter and that diver-tenders are more likely to take shortcuts and change safety standards.

We have found that dedicated tenders often come to training and actual operations more prepared, with the necessary tools such as gloves, stopwatches, clip boards, and so on. They often give more effort to documenting the search and diver profile information.

Dedicated tenders only have to focus on tending when they are training or are working on actual operations; hence, they have the opportunity to become more proficient at tending than team members who have to serve as both divers and tenders. Dedicated tenders get at least twice as much tending learning experience as their diver-tender counterparts.

Dedicated tenders typically make the best safety officers for the reasons explained above. They are less likely to let divers get away with things and are often more detail oriented than diver-tenders serving as safety officers.

Dedicated tenders save the department significant money. Public safety divers first need entry-level diver certification, which can cost hundreds of dollars in addition to salaries if the divers are not working on a volunteer basis. They also need enough dive experience to make them competent and confident enough to move toward entry-level public safety diver certification. Tenders do not necessitate any of these expenses.

Divers need thousands of dollars worth of equipment, even if it is shared. A tender can be outfitted for less than $80, which includes a decent personal flotation device and two sets of gloves. Dive gear must be maintained. Tender gear maintenance consists of watch batteries, paper, and writing utensils.

A team requires a minimum of five team members to make a single dive—a primary diver, primary tender, backup diver, backup tender, and a 90-percent-ready diver. Even with sharing dive gear, it will cost far more to have that team consist of five diver-tenders instead of three diver-tenders and two dedicated tenders.


1. A well-trained tender will be correct within 200 psi of a diver’s air when making an estimation using the diver’s known surface air consumption rate, time and depth down, and current breath/rate.

WALT “BUTCH” HENDRICK, founder of Lifeguard Systems, has been training diving and water rescue personnel for 50 years in more than 15 countries. He is a major innovator and contributor to the water rescue industry, the noted author-publisher of more than 150 works, and an award recipient. Some of his contributions, such as the rescue throw rope bag, the scuba “do-si-do” rescue procedure, and the blackwater contingency plan, have saved lives all over the world.

ANDREA ZAFERES has been teaching and working with thousands of public safety, sport, and military divers with Lifeguard Systems since 1987.








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