Acquired for the external defence of New Zealand, at a cost of about £3,200 each, all four boats were built and engined by John I. Thornycroft & Company at Church Wharf, Chiswick on the River Thames.[1]
As built the class was armed with a single McEvoy spar torpedo, which was designed to be rammed into a vessel and explode beneath the waterline. A single 2-barrelled Nordenfelt gun comprised the total gun armament. The last pair had 18-inch Whitehead torpedoes fitted at build, and these were later retrofitted to Defender and Taiaroa.[1]
On 1 February 1884[1] the first pair were shipped aboard the sailing ship Lyttelton from London to Port Chalmers, New Zealand. The second pair followed on 3 May 1884.[1]
Torpedo Corps units of the Permanent Militia were formed to operate the boats at the four main ports of Lyttelton (Defender), Port Chalmers (Taiaroa), Devonport (Waitemata) and Wellington (Poneke),[2] each with its boatshed and slipway. The boats quickly became obsolete and by 1900 had largely been left to rot.
| Name | Ship Builder | Launched | Fate | |
|---|---|---|---|---|
| Thornycroft & Company, Chiswick | 30 July 1883 | Abandoned at Purau Bay, Lyttelton Harbour and later preserved at the Lyttelton Torpedo Boat Museum | ||
| Thornycroft & Company, Chiswick | 10 August 1883 | |||
| Thornycroft & Company, Chiswick | 30 August 1883 | |||
| Thornycroft & Company, Chiswick | 31 August 1883 |