Late 20th-century Dutch guided-missile frigates carried a large radar dome housing a revolutionary 3D radar that could measure an object’s distance, direction and height at the same time. The radar had a range of 242 miles (390km) and could track over a hundred targets simultaneously, making it the most powerful radar of its time (1975-2000).

The bridge and 3D radar from the guided-missile frigate HNLMS De Ruyter, in service from 1976 to 2001, is now one of the features at the Dutch Navy Museum in Den Helder, along with the 257ft (78m) submarine HNLMS Tonijn that was retired in 1991. Also on display are several other museum ships and detailed exhibits covering Dutch naval history and technology.

Below are trip highlights from October 27th, 2019. Click any image for a larger view, or click the position to view the location on a map. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps.

Tonijn Position: 52°57.83’N, 4°46.33’E The stern of the 257ft (78m) submarine HNLMS Tonijn on permanent display at the Dutch Navy Museum that we’ll be visiting shortly. The ship was launched in 1965 at the Wilton-Fijenoord shipyard near Rotterdam and was in service until 1991.

Torpedo Tubes Position: 52°57.83’N, 4°46.28’E The Tonijn‘s four 21 in (533 mm) bow torpedo tubes. An identical set are at the stern, for a total of eight.

Helm Position: 52°57.83’N, 4°46.28’E Jennifer at the helm of the HNLMS Tonijn.

Henny Fransen Position: 52°57.83’N, 4°46.28’E We spent ages speaking with Henny Fransen, one of the museum representatives on the HNLMS Tonijn. We were impressed how much he knew about the ship and that he was able to answer all of our questions in great detail. It turned out Henny served on the HNLMS Tonijn as a radio operator and knew the ship in intimate detail. We had a great time talking with him.

Shadows of Light Position: 52°57.76’N, 4°46.19’E Monument to those who lost their lives in the service of the Royal Netherlands Navy.

De Ruyter Position: 52°57.77’N, 4°46.17’E The bridge from the guided missile-frigate HNLMS De Ruyter, in service from 1976 to 2001 and once the flagship of the Royal Netherlands Navy. The large dome is characteristic of Dutch guided-missile frigates and housed a revolutionary (at the time) 3D radar that could measure an object’s distance, direction and height at the same time. The radar had a range of 242 miles (390km) and could track over a hundred targets simultaneously, making it the most powerful radar of its time (1975-2000).

Compute Power Position: 52°57.77’N, 4°46.17’E The radar operators post on the HNLMS De Ruyter.

Inside Dome Position: 52°57.77’N, 4°46.15’E Inside the 3D radar dome. The system was made up of two dish-shaped search antennae (partially visible on the right) and two spiral antennae for tracking targets. The search antennae moved vertically and together with the revolving movement of the whole produced a 3D search pattern. The stabilised platform turned at 20 revolutions per minute, creating a force 7 (28-33kts) wind inside the dome.

Abraham Crijnssen Position: 52°57.75’N, 4°46.35’E One of the two triple-expansion steam engines that power the 1930s-built minesweeper Abraham Crijnssen, now on display at the Dutch Navy Museum.

Navy Technology Position: 52°57.82’N, 4°46.14’E The final exhibit we toured was a detailed treatment of Dutch naval technology through the centuries.

Sextant Calibration Position: 52°57.82’N, 4°46.14’E A sextant calibration tool on display in the Naval Technology exhibit at the Dutch Navy Museum.

Click the travel log icon on the left to see these locations on a map, with the complete log of our cruise. On the map page, clicking on a camera or text icon will display a picture and/or log entry for that location, and clicking on the smaller icons along the route will display latitude, longitude and other navigation data for that location. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps.