Shark jaws are used to secure a rope or anchor chain, buoy chain

Not familiar with “Shark Jaws” …Is that a connecting device? Sorry , been away for a while. Familiar with Intercon and Bloodsworth.

Shark jaw.


Thanks Dutchie, is that to connect the unit to the tug with chain while in pushing mode?

Shark jaws are used to secure a rope or anchor chain, buoy chain, and are crucial components of the deck equipment of tugs, anchor handling and multipurpose vessels. Just like towing pins, shark jaws if required can sink hydraulically into the deck. In this way optimum use of the workspace on deck vessels and multipurpose vessels is maintained. For safety reasons they are often remotely operated.


It is a stopper device used to secure a wire or chain while making connection. It has replaced the Pelican hook as a that was inherantly dangerous and now banned in most places.

Shark Jaw was originally a trade name used by Ulstein Trading, but had become generic for all kinds of chain/wire stoppers used on AHTs and tugs.

The one shown by Dutchie is the Triplex Stopper. Another popular brand is the Karmfork:

Both has been copied by others, but are still the safest versions available.

The original Triplex stopper:

PS> The small pin was added to lift the wire/chain off the deck yo make it easier and safer to fit connecting shackles/Kenter links

1 Like

Thank you both sirs for the info, have had the not so delightful experince with pelican hooks, an awkward sledge hammer away from bad shit. We were lucky and stood in the right place.

When we had to use pelican hooks we used a trip wire on the saddle. Standing within sledge hammer range to release a hook is a good way to lose a leg.
When you are standing between a 19 tonne anchor buoy and the stern roller it is nice to know that the karmforks or sharks jaws have a SWL of 500 tonnes or more.

Absolutely corrrect Snort. Pelican hooks are what we worked with back in the day. Thank goodness my guys and I walked away. Wish I had this newer shit while working, developed because some didn’t walk away.Never too old to learn something new.

1 Like

The idea was actually from Pures seiners, where a smaller version of the Ulstein Shark Jaws and Triplex Stoppers were used when connecting the seine wire.

Most of the crews on the early OSVs in Norway were ex. fishermen from the district around Ulsteinvik and Averøya (the home of Triplex)
They brought up the idea that something similar, but stronger, could be developed for OSVs.

PS> That is how the UT 704 design was born as well.


Most modern anchor handling vessels have Rolls Royce Shark Jaws shown in the photos below. The shark jaw is the actual fork that the chain sits in, it is held in place by the locking arms slightly further aft.

Older AHVs have Karm Forks or Triplex Shark Jaws.

Rolls Royce Shark Jaws can be operated totally remotely from the bridge so it is great safety and very quick. A major disadvantage for Karm Forks is you need someone you manually insert and remove a pin from the top, it is slower in that you need to waste time waiting for someone to put the pin in and out.

I think Triplex Shark Jaws were popular on Maersk AHVs, not so common in other companies. But they are said to be potentially very dangerous, someone working on the deck of a Maersk AHV was killed when they Shark Jaws accidentally opened at a piece of mooring equipment hit the person.

As said earlier, “Shark Jaws” were the trade name for the chai/wire stoppers developed by Ulstein Trading in the mid-1970s.
Ulstein Trading also developed the UT design OSVs, PSVs that became the “gold standard” for many years.

Ulstein Trading was sold to Vickers, which again was sold to Roll.Royce and became RR Commercial Marine. In 2019 RRM was sold to Kongsberg and is now named Kongsberg Marine.
Your picture is from their brochure:

The Triplex stopper was developed around the same time. The Triplex company specialises in deck equipment for fishing vessels but branched out to develop equipment for OSVs as well.

PS> The stopper that was prone to open under strain was a Triplex knock-off made in China.

Thankfully I never sailed with anything on the back deck that had a Chinese manufacturers name plate.

1 Like

Neither did these Triplex knock-offs. They carried a western name plate and nothing about the Chinese origin.

PS> I will not mention the brand name but many in the offshore business would know though.

Most non-oil field US tugs are still on pelican hooks.

Karm fork and tow pins for tugs are available:
The tug Boa Odin was a type M330120 installed: