Canterbury Dive

The Bay of Islands Eco Dive Attraction at Deep Water Cove

HMNZS Canterbury History

The RNZN HMNZS Canterbury is a Leander Class Frigate built in Scotland for the Royal New Zealand Navy and commissioned in 1971. She was powered by two steam turbines developing 30,000 horsepower through twin shafts. HMNZS Canterbury was the last steam powered Frigate in service.

F421 was decommissioned by the RNZN in 2005. Like most of the warships before her, she has been sunk as a diving attraction. After the popularity of the Green Peace Rainbow Warrior dive attraction further north in Matauri Bay, F421 is attracting divers from all parts of the world to dive on her at Deep Water Cove in New Zealand’s Bay of Islands.

Canterbury Specifications

Extensively modernized from the 1980’s. The sensors listed below were those fitted to the vessel at the time the vessels were withdrawn from service

Air Search Radar – Signaal LW-08 D Band: Range 265km for 2m2 Target

Air Surface Search Radar – Plessey Type 993 E/F Band

Navigation Radar – Kelvin Hughes Type 1006 I band

Hull Sonar – Graseby Type 750 Medium Frequency Active

Electronic Surveillance – Argo Phoenix intercept and Jammer, Telegon PST 1288 HVU

IFF system: Cossor Mk XII

Data System – Plessey/Marconi Nautis F with Link 11

Weapons Control – RCA TR-76 I Band

2,470 tons Standard, 2,990 Full Load

Guns – 2 x 1 Vickers 114mm Mk 6 – 20rpm to 19km, 1 x Phalanx CIWS – 3000 rpm to 1.5km, 4 x 12.7mm

Missiles – Seacat Missile system removed early 1990’s and replaced by Phalanx.

Anti Submarine – Mk 46 Mod 5 ASW torpedo in Mk 32 Tubes

Helicopter Launched M46 Mod 2 ASW torpedo

Maverick AGM-65 (NZ) Air to surface missile

Depth Charges

M-60 Machine Gun

Countermeasures – 2 SRBOC Mk 36 Mod 1 launchers

373 x 43 x 18 feet (114 x 13.1 x 5.5 metres)
2 x Steam Turbines, 30,000 hp, 2 shafts
28 Knots
30 days or 5500nm @ 15kts: Max speed 28kts

The Canterbury propellers are a UK MOD design, manufactured by Stone Manganese, a large propeller design and manufacturing specialist.

The propellers are made of an aluminum-bronze alloy. Leander Class frigates pioneered ‘agouti drillings’ which were cast into the propeller during manufacture. These allow pressurised air to be fed through the body of the propeller and out through vents in the leading edge of the individual blades. This feature reduced the prospect of cavitation thus lessening erosion and reducing underwater noise – an obvious advantage for an anti-submarine frigate.

The twin five blade propellers fitted to earlier Type 12 frigates (i.e. “Otago” and “Taranaki”) did not have this feature as they were cast solid. These propellers are “handed”, i.e. the port and starboard propellers were outward turning when the ship traveled forward.

Diameter – 12′

Pitch – 17′ 8″ @ .7 radius

Area – 79.49 sq ft

Weight – 4.8 ton

One of the propellers purchased by the Far North District Council will be donated to a local community group to be mounted as a land based memorial.

The Dive Location

Deep Water Cove is located near the tip of Cape Brett at the southern entrance to the Bay of Islands. It was the site of Zane Grey’s first deep sea angling base and an early whaling station. It is now a nature reserve. The cove is a popular anchorage and shelter for boats after they first enter the bay. There is no road access to the cove but a popular 20km 8 hour Department of Conservation (DOC) walk to Cape Brett light house passes by. Guided walking tours are also offered. The surrounding coastline is already a popular fishing and diving location. This is being further enhanced by the Canterbury and the new marine life it is attracting.

The Canterbury Dive

35°11’34.69″S  174°17’48.70″E