For me, a sailing knife needs four key essentials – a blade, shackle key, marlin spike and (the least important) a bottle opener, writes John Stickland. The Opinel No 9 Ocean Knife is missing the bottle opener but has a blade with an integrated shackle key and marlin spike in the handle plus a high-pitched whistle.

The stainless steel blade is half-serrated, which worked well for cutting rope, has a good point and it is also coated in PVD (Physical Vapour Deposition), a vacuum coating process which creates a corrosion-resistant layer. The traditional Opinal Virobloc safety closure also prevents accidental opening.

The shackle key offers good purchase. Credit: Katy Stickland

The 9cm blade is more than sufficient for everyday use and fits comfortably into the pocket of trousers or oil skins. One-handed opening is tricky due to the shallow depth of the blade when the knife is closed.

The fibreglass-reinforced handle provided some grip in wet weather and has a good lanyard attachment point.

The shackle key is a good size and fits a standard shackle, but it is located in the rough centre of the blade. Whilst this provides an excellent purchase for locking and unlocking a shackle, the blade tip can potentially damage whatever the shackle is attached to, such as a sail or jackstay, unless you are very careful.

The marlin spike is a good size and non-locking. Credit: Katy Stickland

The marlin spike is a good size and not too pointy; it is non-locking but has a knurled edge for grip and to help keep it in place. A strong magnet in the handle prevents the spike from accidentally opening.

The Opinel No 9 Ocean Knife weighs 80g and is available in blue, red and yellow.

There is a whistle in the handle and a good lanyard attachment point. Credit: Katy Stickland

Overall, you get the quality of a traditional Opinel knife with a sharp blade, good marlin spike and an adequate shackle key in a handy size.