IRN Castillo (GB-1924 (1938-mod))
The Castillo class was the Iberian navies first try at a long range patrol vessel. The class turned out to be neither one thing or another. Too many cooks spoiled the design. A speed of 26 knots was eventually specified, which required a larger propulsion system which used more fuel and took up more space which allowed less space for fuel stowage. The armament specified was two single 5.9", two 3" AA and four machineguns. This was a large amount of requirements for such a small ship. Once the four ships were completed they were supposed to rotate around the Iberian overseas colonies and act as training ships as well as their patrol duties. Unfortunately the ships short range tied them to the colony base and each ship spent five years at its assigned colony, then a break for an extended refit then back to duty.
In 1938 a decision was made to spend some money to upgrade the ships and rearm them with a modern armament and refit the propulsion system. The renewal of the propulsion system was made possible by access to the Germanic States range of marine diesel engines. The single six inch were replaced with twin 4" dual purpose mountings, quad 2 pounder replaced the single 3", while the machine guns were replaced with 20mm cannons. The smaller but of same power propulsion system allowed for an increase in fuel stowage for an almost double of the range of the ships. A vast improvement over the original concept.
| Displacement | 1,500 tons std, 2,050 tons full load |
| Length | 249 ft |
| Breadth | 35 ft |
| Draught | 10 ft |
| Machinery | 2 shaft diesel engines, 10,000bhp |
| Speed | 26 knots |
| Range | 9,000 at 10 knots |
| Armament | 4 x 4" (2x2) 8 x 2pd (2x4) 4 x 20mm (4x1) |
| Complement | 145 |
| Notes | IRN Castillo |
Twin forward 4" mounting.