[naz]

i consolidated the tech i posted in another thread into this one post

tech about submarining and spine compression

Quote:it is important for the shoulder straps to extend rearward at no more than a 15 degree downward angle from the horizontal. If the shoulder straps are mounted improperly (e.g. looping the strap over the shoulder and down to a floor mount) you greatly increase the risk of severe injury from spinal compression. Submarining is also a concern with a 4-point harness system for 2 reasons. 1) Since the shoulder straps pull up on the lapbelt, it is possible to raise the lap belt above the pelvic crest bones and onto the abdomen. If the lap belt is too high, serious injury can occur to internal organs. That's why 5 and 6-point systems are used in racecar restraint systems. However, it is not possible to use these anti-submarine straps without the installation of an aftermarket seat that allows the straps to pass directly down to the floor. It is not safe to loop the anti-submarine belt over the front of the seatbecause it does not provide the correct downward force and still allows submarining. 2) A 3-point system allows some chest rotation. The right side of the chest moves forward in an accident, decreasing the tendency to slide under the lapbelt. In all but one 4-point systems, this rotation in prevented increasing submarining risk. Schroth makes a 4-point harness with an anti-submarine feature that does allow some chest rotation and decreases submarine risk.

source


sample rule book showing ineligibility of 4pt Y strap harness

here is the rule book from national auto sport association (nasa), a large sanctioning body in the US. that holds HDPE, time trial, club race and other events

http://www.nasaproracing.com/rules/ccr.pdf

section 15.5 (page 71 in the pdf file) discusses the rules for driver restraints that are permissible at nasa events

note that your harness configuration would fail on the following points
15.5.1 : your harness is 4 point, and not 5, 6 or 7 point
15.5.6 : the mounting of the shoulder harness is below a 20 degree line from horizontal from your shoulders
15.5.8 : your are using a Y type strap that does not have individual mounting points for each shoulder strap

recommended alternative to 4pt harnesses: OE belt with CG lock

there is a product called CG LOCK (http://www.cg-lock.com/track.html) that retains the safety advantages of the OE 3 pt belt and closely simulates the 'tight' feeling from being in a 4/5/6pt harness. EDIT: it does not give show points but it works