Technical Tip

Stainless does not mean Stainproof

A common misconception among divers is that stainless steel does not corrode at all. There are various types of stainless steel, each with different corrosion properties, that make a specific grade more or less suited to a particular application. Because there is no perfect stainless steel, the selection of the grade is often a compromise between corrosion resistance and malleability. Stainless grades selected because they hold a sharp cutting edge will corrode relatively fast compared to other grades. The most corrosion resistant grades are not usually a good choice for bolt snaps and hand tools because depending on the use application they may not offer the best wear resistance or may be too brittle.

Stainless does not mean Stainproof and all diving products made of stainless steel must receive some basic care to help minimize corrosion. Rinse any stainless steel components in dive equipment with fresh water after diving or when otherwise in contact with salt water, allow them to dry and do not store them in damp or moist environments. Make sure any storage sheath or pouch is also rinsed and allowed to dry before returning the stainless item to the pouch. When rinsing bolt snaps, be sure to work the bolt action several times to eject any saltwater trapped in the slider and spring mechanism. In particular, avoid storing stainless steel near or in contact with other metals having strongly dissimilar electropotentials, especially aluminium, such that moisture can induce galvanic corrosion. In cases of galvanic corrosion where the stainless item is in close proximity to some types of metals, rust or other colour stains will electrolytically transfer to the surface of the stainless item.

An invisible film forms on the surface of stainless steel when it's in contact with oxygen. This allows it to withstand damage from corrosives including many acids, bases, and detergents, as well as salt water. However, depending on envirionmental conditions you may notice some surface 'stains' that can form on various stainless items. In general these are cosmetic in nature and we recommend you allow the cosmetic stains to remain when practical. Using an abrasive is more likely to remove the invisible corrosion resistant film that forms on stainless, allowing corrosion to spread and ultimately making the corrosion worse.

Properties of Stainless Steel

Hardness - As hardness increases, metals become more wear resistant but they may be less malleable. Some types of stainless steel harden by cold working, and others can be heat treated. The 300 series hardens by cold working, many in the 400 series can be hardened by heat treating.

Formability - Stainless steel is generally formable and bendable, but types that harden by cold working can require more force to bend than carbon steel.

Machinability - During machining, stainless steel can become gummy and stick to cutting tools, making it typically more difficult to machine than steel.

Weldability - Take care to clean stainless steel before and after welding operations. Contaminants, such as lubricants and particles from grinding tools, will reduce corrosion resistance at welded points.

Finish - Stainless steel does not always have a shiny finish. In fact, stainless steel is available in a number of finishes, ranging from an unpolished, dull surface to a reflective mirror-like shine.

D McLennan

Wreck Dive | Boat access

Steel Steam Bucket Dredge | Max Depth: 58 m (190 ft) — Graveyard

The D McLennan was a steel dredge, built 1912, and scuttled in the Victorian Ships' Graveyard on 8 June 1949. She rests on a sandy seabed, 58 metres deep.

D McLennan Shipwreck History — Built in 1912

D McLennan
© Melbourne Harbor Trust

The D McLennan was a steel steam bucket dredge of 424 tons gross, built in 1912, by Koninklijke Nederlandsche Grefsmedery, in Leyden, Holland. The overall length of the vessel was 165.5 ft (50 m), with a beam of 29.2 ft (8.9 m) and draught of 8 ft (2.44 m).

The D McLennan was built for the H.A.M. No. 6 and purchased second hand by the Melbourne Harbour Trust from Batavia (present-day Jakarta, Indonesia), and brought into commission in 1925. The dredge was capable of dredging to 59 feet and it worked on various dredging projects within the port until it was condemned in 1949.

D McLennan Sinking — Scuttled 8 June 1949

After being stripped of all items of value, the D McLennan was towed out into Bass Strait and scuttled in the Victorian Ships' Graveyard on Wednesday 8 June 1949.

Heritage Warning: Any shipwreck or shipwreck relic that is 75 years or older is protected by legislation. Other items of maritime heritage 75 years or older are also protected by legislation. Activities such as digging for bottles, coins or other artefacts that involve the disturbance of archaeological sites may be in breach of the legislation, and penalties may apply. The legislation requires the mandatory reporting to Heritage Victoria as soon as practicable of any archaeological site that is identified. See Maritime heritage. Anyone with information about looting or stolen artefacts should call Heritage Victoria on (03) 7022 6390, or send an email to heritage.victoria@delwp.vic.gov.au.

Bass Strait Warning: Always keep an eye on sea conditions throughout any shore or boat dive in Bass Strait on Victoria's coastline. Please read the warnings on the web page diving-in-bass-strait before diving or snorkelling this site.

Traditional Owners — This dive site does not lie in the acknowledged traditional Country of any first peoples of Australia.

D McLennan Location Map

Latitude: 38° 22.104′ S (38.368392° S / 38° 22′ 6.21″ S)
Longitude: 144° 25.983′ E (144.433055° E / 144° 25′ 59″ E)
Datum: WGS84 | Google Map
Added: 2012-07-22 09:00:00 GMT, Last updated: 2022-05-12 03:26:34 GMT
Source: Book - Victoria's Ships' Graveyard GPS (verified)
Nearest Neighbour: Bunyip, 716 m, bearing 238°, WSW
Steel Steam Bucket Dredge, 424 tons.
Built: Leyden, Holland, 1912.
Scuttled: 8 June 1949.
Victorian Ships' Graveyard, Bass Strait.
Depth: 58 m.

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DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.

The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.