As TO Wx3 back in 1974 I took part in the operational inspection of a Tribal class frigate, one that had no flight deck but just a space for winching. Their ops spec called for a HIFR capability day and night. I drew the short straw and found myself doing the night section.
All was well until we gave the sign that fuel was flowing whereupon the ship was released from the requirement to maintain course and speed and it resumed its rapid and regular changes of both designed to prevent enemy submarines gaining a resolution good enough to launch a torpedo. What followed was a harrowing fifteen minutes of being towed around like a dog on a lead that severely tested my skill and the aircraft's capabilities.
The concept was born out of the Wx3's low fuel endurance, just 1.30 on task. This meant the helicopter would spend a lot of time flying back and forth between its mother ship and its screening sector. At that time Russian subs were getting to be a threat at quite long range so the screen had to be further out exacerbating the problem of low fuel. The outer screen was the responsibility of the ASW helicopter but the inner screen was made up of ASW frigates so with HIFR the need to return to 'Mum' was removed.
Sore arses were the likely result. Luckily I never had to do it in an operational environment. HIFR was a feature of Sea King ops too and with that beast you started with a five hour plus mission length so that really would give you a sore bum.
G.
Just done a little homework on the Tribal class frigates and clearly they did all have a small helideck - for the WASP. From my perspective (Wessex and Sea King driver) what looked like a neat spot for a Wasp was clearly mis-identified as something too small to accommodate anything !! Tribal flight commanders clearly lived a challenging life!