I've ditched my old measuring tape and moved over to using the awesome HTO LRF Measure. It's basically a handy, telescopic fish measure that expands from 15cm to 50cm. I recently started logging what species and sizes of fish I catch and where along the coast (a bit like I already do in freshwater) and this tool is proving really useful for quickly measuring each fish before returning, unharmed. I just keep it to hand in the water-bottle holder on my LRF bag. The LRF measure has proved to be a great unhooking tool too. Even a hectic Mackerel can be successfully subdued and unhooked. The curved 'gutter' keeping the fish in place. Much kinder to the fish than placing on a dusty or hot surface. The measure acts as a great means of capturing photos.
Full plastic design. Nothing to rust. The sliding mechanism is robust. A complete bargain at only £3.99