Saturday evenings in the late '50s or early '60s there was a live TV show ('Saturday Night Live' or something) fronted by Raymond Baxter which tried to do something spectacular each time; one time it was a locomotive crash at Longmoor military railway and another was live shots of an aircraft carrier.
I remember Baxter saying that when catapulted away, the strop was left to simply fall off imto the water and that each strop cost £7-0s-0d (pre 1971 money if you don't know)