Flat-iron gunboat
The Norwegian flat-iron Tyr remains in service under the name Bjorn West, at last report entering Eidsvik shipyard in May 2014 for restoration.
George Rendel was put in charge of the new venture, and the vessels designed under his leadership were based on a small craft used by the Armstrong factory to test heavy guns.
[2] With the assistance of the leading gunnery expert Admiral Sir Astley Cooper-Key, he turned these craft into a gunboat designed for defensive coastal operations.
No rigging of any sort was provided, and twin screws were fitted, allowing for a much reduced draught while at the same time making them highly manoeuvrable.
This may account for some of the later vessels carrying monstrous 15- and 16-inch guns; flat-irons armed in this fashion were not used for long, probably because their weapons were all but useless except against a stationary target in a flat calm.
[4] According to Professor Andrew Lambert the Royal Navy flat-irons succeeded in their task of deterrence, and were a key asset to the capability of coastal offensive operations.
[7] The Australian colonies of the British Empire purchased a number of gunboats for coastal defence during the 1880s, and while they were described as "flat-irons", they were masted, and Protector was almost the size of a light cruiser.
Argentina purchased four flat-iron gunboats from Laird Brothers, Birkenhead and J & G Rennie & Co, Greenwich,[8] in 1875; they were grouped in two classes: Pilcomayo and Constitución.
A further pseudo-Rendel gunboat (Hoi Tung Hung) was built locally to the lines of the "alphabetical" flat-irons, but constructed from wood sheathed in iron.
[5] The German Navy (Kaiserliche Marine) built eleven large Rendel gunboats (Panzerkanonenboot) of the Wespe class at AG Weser, Bremen between 1875 and 1881.
[15] In the late 1880s 2 large Rendel gunboats were designed and built by Armstrong Mitchell & Co.'s Elswick Works to a contract by the Italian War Ministry.
Thirty-one flat-iron gunboats were built in the Dutch shipyards Christie, Nolet & De Kuyper and Feijenoord Mij in the years 1870 to 1880.
They were gradually decommissioned by the Royal Norwegian Navy after World War II, but the Gor-class gunboat Tyr was still operating as the civilian ferry Bjørn West 100 years after she was built.
[4] They were of sound construction, and many stayed in service in support roles, with a number ending up as gunnery tenders,[22] lighters, tank vessels and dredgers.
[4] Professor Andrew Lambert later argued powerfully that they were designed for coastal assault as successors to the gunboats of the Crimean War "Great Armament", and that they succeeded in their deterrent role.
[2] Due to their lack of speed and limited armament they were of little value in defence of a coast or harbour, but they were ideally suited for bombardment of shore fortifications where the Royal Navy enjoyed complete command of the sea.
[3][4] The Medina class were a development of the flat-iron concept which resulted in an iron coastal gunboat fitted with three masts and carrying three 6.3-inch 64-pounder rifled muzzle-loading guns.
