Fitting the Backplate and Secure Harness

Selecting a Backplate Size
Halcyon currently offers two sizes of Backplates:
  • Standard: 15.5” tall by 10.25” wide
  • Small: 14” tall by 9.25” wide
When selecting a size, consider diver height, torso length and width of shoulders. The plate should sit comfortably on the divers back, without excessive pressure on the hips and should be wide enough to avoid pinching between the divers shoulder blades.


Fitting Your Secure Harness:
  • Fit the backplate while wearing your exposure suit.
  • Confirm the weave of the Secure Harness is correct.
  • Adjust the length of the shoulder straps & check position.
  • Position the height of the shoulder D-rings.
  • Check the Secure Harness is evenly adjusted with no impingement of arm/shoulder movement.
  • Adjust the waist strap. Waist buckle to right of center.
  • Position the left waist D-ring.
  • Adjust the length of the crotch strap.
  • Position the rear D-ring.


Final Adjustments
  • Harness sizing adjustments will be made at the tri-glides on the back of the plate. Alterations can easily be made to accommodate other suit types.
  • Shoulder straps should be snug yet easy to doff/don and appropriate for arm range of motion (ROM), but tight enough to secure the tanks when underwater. A quick check to confirm a three- to four-fingers width between the harness and the exposure suit is a good guideline for the first fit. While wearing the harness and exposure suit, you should be able to reach back with both hands and touch the top of the back plate. This is a quick check approximating the correction position for the plate.
  • Waist band should be snug, without compressing the diaphragm/waist. The waist buckle should sit to the right of the body centerline; this avoids catching the buckle in the loop of the crotch strap.
  • Following the harness fitting, verify the crotch strap is secure but not too tight. There should be approximately 1/2 inch of space above the waist band. Adjust for comfort if necessary.
  • Shoulder D-rings should be level; easy to reach. The diver should be able to reach across their chest and touch the opposite shoulder without interference from the d-ring. Most divers position the d-ring too low. In order to verify proper height, divers should raise their arms parallel to the shoulders, bending their arms and touching their upper chest; the d-ring should rest in this location.
  • The left hip D-ring should be placed under the armpit and adjusted slightly for diver mobility.
  • Adjustments for comfort and improvements in range of motion may be necessary. One should expect to adjust the harness after the first few dives in order to achieve a proper fit.
  • A complete Sizing Description is in the BC System Owners Manual.