Seafom Commercial Corner

Unlike sport divers, commercial divers rarely have the oppurtunity to dive under

ideal conditions. Little or no visibility, rough sea conditions, extreme depths and

long hours under water are but a few of the difficulties that the average working

diver faces each day. A simple inspection job at 80 fsw under good conditions

may require only the use of SCUBA whereas a major salvage operation in 350 fsw

would require the divers to be ?hooked in? to a mixed gas-saturation (sat) system

for weeks at a time. A construction diver will spend anywhere from 4 to 8 hours

underwater each day depending upon the particular task assigned to him. For

Example: a diver breaking rock on the bottom using an 85 lb pneumatic

jackhammer would have only a limited bottom time to endure the physical stresses

he would encounter whereas an inspection diver would most likely spend the

whole day at his job, assuming of course, that the no decompression limits are not

a factor. Therefore proper training, detailed planning, excellent physic

al fitness and good equipment are all mandatory requirements in any commercial

diving operation in order to ensure the safety of the divers.

On the equpment side, the most commonly used system in construction diving is a

surface-supplied diving system (SSDS). These systems not only increase the

diver?s productvity but also afford him maximum comfort, mobility and safety. A

typical SSDS consists of a topside divers? umbilical, rackbox, a helmet or band

mask and a Diver Radio. The air supply is a low pressure compressor (generally

gas or diesel driven) complete with a receiver tank, air filtration system, and an

emergency ?back-up? air supply. The rack box is a pneumatic control station

which allows the tender to immediately switch over to the back-up air supply in

the event of an emergency. The umbilical (approx. 350 ft.) is composed of a

special flexible, non-kinking, non-toxic air hose, life-line, communications cable and

pneumo hose (accurately monitors diver?s depth). The helmet or band mask ( of

which there are many types available) are equipped with microphone,earphones

and a breathing system which can supply air to the diver by either deman

d regulator or free-flow. The dive radio facilities direct voice communicartions

between topside personnel and up to 6 divers. It also allows the diver/topside

conversation to be recorded directly into a VTR u/w video during underwater

inspection work.

An (AIR) SSDS is a basic commercial diving system which can safely handle the

requirements of most diving jobs down to a depth of 190 fsw. Diving operations

beyond this depth however generally use ?mixed-gas? and therefore require much

more sophisticated equipment, specially trained divers and a large support crew.

For Example, an (AIR) SSDS with two divers down would require a support crew of

five for a total of seven personnel - while a (MIXED-GAS) SSDS with 2 divers

down would require a minimum support crew of 13 for a total of (15) personnel.

Mixed-gas diving is also very expensive compared to air diving, typical mixed-gas

operation can easily exceed the cost of $10,000 US per day!

Remember - NEVER attempt to use any dive equipment without having been

properly trained in its use, you may be risking not only your life but the lives of

others!

A little Commercial Divers? humour: Q: Where do you find DIVERS in the Yellow

Pages? A: Between ?Distillers? and ?Divorce?! See you next time!