![ROV working on a subsea structure](https://upload.wikimedia.org/wikipedia/commons/9/99/ROV_working_on_a_subsea_structure.jpg)
Anchor Handling Tug Supply (AHTS) vessels are mainly built to handle anchors for
oil rig
{{about, , the mnemonic OIL RIG, Redox
An oil rig is any kind of apparatus constructed for oil drilling.
Kinds of oil rig include:
* Drilling rig, an apparatus for on-land oil drilling
* Drillship, a floating apparatus for offshore oil drilling ...
s, tow them to location, and use them to secure the rigs in place. AHTS vessels sometimes also serve as Emergency Response and Rescue Vessels (ERRVs) and as supply transports.
Many of these vessels are designed to meet the harsh conditions of the
North Sea
The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...
, and can undertake supply duties there between land bases and drilling sites. They also provide towing assistance during tanker loading, deepwater anchor handling, and towing of threatening objects.
AHTS vessels differ from
platform supply vessel
A platform supply vessel (PSV) is a ship specially designed to supply offshore oil and gas platforms. These ships range from in length and accomplish a variety of tasks. The primary function for most of these vessels is logistic support and tr ...
s (PSVs) in being fitted with winches for towing and anchor handling, having an open stern to allow the decking of anchors, and having more power to increase the
bollard pull
Bollard pull is a conventional measure of the pulling (or towing) power of a watercraft. It is defined as the force (in tonnes force, or kilonewtons (kN)) exerted by a vessel under full power, on a shore-mounted bollard through a tow-line, commonl ...
. The machinery is specifically designed for anchor handling operations. They also have arrangements for quick anchor release, which is operable from the bridge or other normally crewed locations in direct communication with the bridge. The reference load used in the design and testing of the towing winch is twice the static bollard pull.
Even if AHTS-vessels are customized for anchor-handling and towing, they can also undertake, for example, ROV (
remotely operated underwater vehicle
A remotely operated underwater vehicle (technically ROUV or just ROV) is a tethered underwater mobile device, commonly called ''underwater robot''.
Definition
This meaning is different from remote control vehicles operating on land or in the ai ...
) services, safety/rescue services, and supply duties between mainland and offshore installations.
At some point in time, world's strongest tug of any kind was the Island Victory (Vard Brevik 831), an AHTS vessel with a bollard pull of .
See also
*
Salvage tug
A salvage tug, known also historically as a wrecking tug, is a specialized type of tugboat that is used to rescue ships that are in distress or in danger of sinking, or to salvage ships that have already sunk or run aground.
Overview
Few tugbo ...
*
Emergency tow vessel
An emergency tow vessel, also called emergency towing vessel, (ETV) is a multi purpose boat used by state authorities to tow disabled vessels on high seas in order to prevent dangers to man and environment. The disabled vessel is either towed to ...
References
{{Reflist
External links
The Bourbon OrcaBourbon Orca, yno 273, Ulstein VerftIcebreaker AHTS Balder Viking
Shipbuilding
Ship types
Petroleum technology