Backplate Harness Systems: The Good, the Bad and the Ugly

Many extended range divers opt to use the patented Stainless steel or Aluminum Backplate harness system offered by Ocean Management Systems Inc. or chooses other manufacturers product. A Good Backplate requires certain manufacturing procedures whereas the bad and the ugly ones are relatively easy to make. There are a number of companies as well as garage shop operations offering very similar Backplates to the OMS patented design and sometimes at a lower cost.

So you ask what's the difference, it looks similar to yours so why shouldn't I purchase the other guys Backplate?

We can think of plenty of reasons not to purchase many of the Backplates offered and after you read this article you can make an informed purchasing decision (unless the training agency dictates the use of their own equipment).

First a little about the OMS manufacturing process:

A quality non corroding 300 series or 400 series stainless steel is selected and then die cut to the correct shape complete with holes and slots. This is called the Blanking Operation. The "Blank" Backplate then goes through the ultra critical Radius Coin Operation. This procedure completely de-burrs the plate and creates "soft as a baby's bum" edges, slots and holes. This deburred blank then goes through a Two (2) Station Forming Procedure. This process results in precision forming, resulting in better reproducibility, uniformity, and maintains "flatness" in those areas adjacent to the slots and holes. In 1995 OMS invested approximately $70,000 dollars in a line die and peripheral equipment to insure that the engineering designs concepts would be achievable throughout the manufacturing process.

The end result:


1. Superior and Consistent Fit: The OMS Backplate is engineered to fit closer to the cylinders preventing "Gapeosis", creating a "tighter profile" and as a result reduces drag.
   
   
2. Superior Form: The edges on the outside of the OMS Backplate are "radius formed" to fit the OMS BC, thereby preventing Backplate chafing of the BC.
   
   
3. Superior Function: The Webbing that passes through the slots in the Backplate must continue to function throughout the dive season without appreciable abrasion.
   
   
4. The slots, holes and edges of the OMS Backplate are fully deburred eliminating sharp edges that can cut you and your harness system. See Figure 1

And Now "The Bad and the Ugly"

Typically cheap Backplates are manufactured using shortcuts so that they can be either offered at a lower price or increase the amount of money you take out of your pocket and place in theirs. Usually these plates are either laser or mechanicaly cut, producing extremely sharp edges. The Backplates are then "one-step" formed. One step forming has disadvantages:
The shape of the plate cannot be maintained as accurately as a two (2) form process. Therefore you will see plate to plate variations in fit as well as appearance. You may also see "bulging" or deformation in the slot areas. Some manufacturers attempt to mask these defects by polishing the Backplate.     The next step may be a manual de-burring procedure to soften sharp edges or no de-burring at all. The manual de-burring operation inevitably misses critical radiuses in the slot areas where the harness passes through and as a result severely abrades the webbing (Figure 2). Severely abraded webbing that fails may cause loss of equipment and subsequent injury.
    No de-burring leaves sharp edges on the outside of the Backplate (causing abrasion or cuts to your BC) as well as sharp edges on all holes and slots.

In our opinion: If a dive training agency requires you, as part of their course requirement, to purchase a defective Backplate, i.e. one that has sharp edges, slots and holes, gracefully refuse and go out an purchase a properly manufactured backplate. In the long run you will replace fewer harnesses, spend less money and dive safer.

If you have already purchased a defective Backplate that consistently "chews" up your harness webbing call the manufacturer and voice your concern.