Rescue and salvage ships are a type of military salvage tug. They are tasked with coming to the aid of stricken vessels. Their general mission capabilities include combat salvage, lifting, towing, retraction of grounded vessels, off-ship firefighting, and manned diving operations. They were common during World War II.
The Lapwing-class salvage ship USS Discoverer (ARS-3) as USC&GS Discoverer c. 1935
The Diver-class salvage ship USS Safeguard (ARS-25)
The Anchor-class rescue and salvage ship USS Restorer (ARS-17)
The Weight-class salvage ship USS Swivel (ARS-36).
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.
French salvage tug Abeille Bourbon which also serves as an emergency tow vessel (ETV)
USNS Grapple Example of modern naval rescue and salvage ship