Oro has been a restricted-access military base since the early 1900s, when Russia built a fortress here, and has only recently been opened to the public as part of Finland’s Archipelago National Park. After a century of military activity, the island is full of fortifications and ruins, most open and publicly accessible. And the park service has done a great job of adding trails, information signs and picnic tables throughout.

We anchored off Oro for three nights and spent a good part of a day exploring the ruins in their entirety. Blog reader Markus Rautio thought we’d find the island interesting and he was right. This will be on this summer’s highlight list.

Below are trip highlights from May 10th and 11th, 2019 at Oro, Finland. 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.

5/10/2019

Sunrise Position: 59°57.89’N, 20°55.97’E 5:15am sunrise underway from Kokar to Oro. The days are getting longer.

Lukarsbaden Position: 59°52.19’N, 21°54.56’E Lukarsbaden is barely large enough to hold the light standing on it.

Tordmulharun Position: 59°52.70’N, 22°0.87’E Tordmulharun light and a typical Finnish range marker. The center yellow stripe of the range marker is lit at night, but we’ll probably never see that with the longer daylight hours we’re heading into.

Vano Position: 59°51.87’N, 22°11.43’E The village of Vano to our north.

Turva Position: 59°50.01’N, 22°18.02’E The 315 ft (96m) offshore patrol vessel Turva is the largest in the Finnish Boarder Guard fleet and the first to be powered by LNG.

5/11/2019

Sunrise Position: 59°49.85’N, 22°19.80’E Sunrise through the mist at the anchorage off the island of Oro.

Damaged Wires Position: 59°49.85’N, 22°19.80’E We’re using an I2C bus to connect a Raspberry Pi running in the lazarette with a LCD screen we use to show status information at the front of the engine room. Strictly speaking, I2C is designed to be used between components on a circuit board (Inter-Integrated Circuit), so we’re kind of pushing our luck asking the protocol to run reliably beyond 10 meters. It’s been doing well but we’re seeing voltage loss on the 5V bus that powers the remote I2C devices. James put an additional 5V power tap onto the I2C power feed this morning and, during installation, made a mistake that led to short that did some damage before the fuse released. These are some of the damaged wires.

Fog Position: 59°49.85’N, 22°19.79’E We were planning to tour the military sites on the island of Oro today, but a thick fog has settled over the area—this has been the view pretty much the entire day. So we’ll get a few projects done around the boat instead and visit tomorrow.

5/12/2019

Oro Gasthamn Position: 59°48.60’N, 22°20.13’E Our tender tied off at the Oro Gasthamn for walking tour of the island. It’s a Sunday and three boats were at the marina when we arrived, but all had left by the time we returned late in the day.

Dock Position: 59°48.61’N, 22°20.14’E The docks in Sweden and Finland often are beautifully built to follow the contour of the rocks.

Martin’s Shipyard Position: 59°48.56’N, 22°20.28’E Marine ways on the island of Oro. A shipyard has been in this location since the early 1900s.

Gun Barrel Position: 59°48.47’N, 22°20.29’E Massive 12-inch (305mm) gun barrel, built in St. Petersburg in 1915.

12-Inch Obuhov Position: 59°48.43’N, 22°20.34’E This rare 12-inch (305mm) Obuhov gun on Oro has a range of 28 miles (45km) and fires shells weighing nearly 1,100lbs (500kg). The life expectancy of the barrel is only 200 firings.

Lunch Position: 59°48.42’N, 22°20.36’E We found a wonderful picnic lunch spot on Oro just beyond the Obuhov gun.

Kasarmihotelli Position: 59°48.41’N, 22°20.17’E The Kasarmihotelli in a converted military barracks building.

Second Obuhov Position: 59°48.37’N, 22°20.02’E James standing on the barrel of a second 12-inch (305mm) Obuhov gun, viewed from a smaller adjacent gun.

Naval Observation Post Position: 59°48.50’N, 22°19.93’E This naval observation post was added in the 1980s atop a 1950s artillery observation tower and is one of several buildings on the island still under military control with restricted access. The Archipelago National Park service has done an excellent job of making the island accessible with well-marked trails and dozens of interpretive signs describing the island’s historical and natural features.

Artillery Observation Tower Position: 59°48.25’N, 22°18.96’E An artillery observation tower, used for providing guidance to the artillery battery as the target can rarely be seen from the gun itself because it is relatively low.

Tunnel Position: 59°48.20’N, 22°18.81’E Tunnel under the 6-inch gun barracks near the southern tip of the island. Except for a few buildings that were off-limits, most of the island’s military infrastructure was open and accessible. We really enjoyed being able to explore it all.

6-Inch Gun Position: 59°48.19’N, 22°19.06’E One of several 6-inch guns at the south end of Oro.

Solkuro Position: 59°48.15’N, 22°18.80’E Beautiful Solkuro beach looking east from the southern end of Oro.

Sauna Position: 59°48.15’N, 22°18.80’E One of many saunas we found throughout the military infrastructure.

Picnic Table Position: 59°48.15’N, 22°18.82’E The parks service had placed picnic tables at several viewpoints throughout the island.

Suspension Bridge Position: 59°48.15’N, 22°18.71’E Jennifer loves suspension bridges and was thrilled to discover this one.

Light Position: 59°48.08’N, 22°18.63’E We saw these odd lights all around the island, all hand-built. Some have two fluorescent lights in hand built fixture. Here a high-wattage bulb is housed in an outdoor garbage can with a Plexiglas cover. It’s hard to be sure what they are for, but we guess it might be a research study using the lights to attract insects or animals.

Munitions Storage Position: 59°48.05’N, 22°18.64’E Munitions storage for the battery at the southern tip of Oro.

Canet Gun Position: 59°48.06’N, 22°18.61’E James standing on one of the four 6-inch Russian-made Canet guns that were mounted on the southern tip of the island during fortress construction in the 1910s.

Cobbled Roads Position: 59°48.18’N, 22°18.62’E About 4.7 miles (6km) of cobbled roads were built on the island to transport heavy artillery pieces between the harbours and the batteries and barracks.

Radar Tower Position: 59°48.38’N, 22°18.76’E Modern radar tower on the west side of Oro, above another gun emplacement.

Wild Pansy Position: 59°48.48’N, 22°18.83’E Wild pansies were in bloom through all over Oro.

West Beach Position: 59°48.47’N, 22°18.86’E West Beach on Oro viewed from the gun emplacement beneath the radar tower.

Walkway Position: 59°48.50’N, 22°18.91’E This walkway led to an underground sauna. It was a strange path in that the overhead timbers were less than 5ft above the path, so you had to really crouch down to enter.

Trail Position: 59°48.58’N, 22°18.97’E You’d be hard-pressed to get lost on Oro. We almost always could see at least two trail marks ahead of us.

Mortar Hill Position: 59°48.59’N, 22°19.17’E The Mortar Hill bunker was built in the 1970s in the center of the island to defend Oro should an enemy successfully land. We walked through a series of underground tunnels and fully explored the whole facility.

Looking Out Position: 59°48.59’N, 22°19.19’E Jennifer looking out from the steel armored observation point visible in the background of the previous photo of Mortar Hill. The thick-steel structure would allow someone to safely observe during an enemy shell attack.

View East Position: 59°49.03’N, 22°19.68’E The view east across another gun on Oro.

North Fortifications Position: 59°49.68’N, 22°19.15’E The air defense positions on the north end of Oro were built in the 1980s.

View North Position: 59°49.69’N, 22°19.14’E Looking north from an observation post in the North Fortifications on Oro.

Barracks Position: 59°49.67’N, 22°19.15’E Beds left in the barracks in the North Fortifications.

Dirona Position: 59°49.66’N, 22°19.18’E A view to our anchorage of the northern end of Oro. Anchoring is prohibited anywhere along the island, so we found a great spot a little to the east.

Hedgehogs Position: 59°49.57’N, 22°19.23’E One of several hedgehogs along the northwest shore, designed to prevent heavy armored equipment from landing and driving up the beach.

Air Raid Shelter Position: 59°49.54’N, 22°19.28’E Jennifer descending into an air raid shelter just south of the North Fortifications.

Sauna Position: 59°49.54’N, 22°19.28’E Another sauna.

Break Position: 59°49.40’N, 22°19.19’E Taking a break and enjoying the view from another wonderful picnic table. In the background is a modern artillery observation post, built in the 1980s.

120mm Bunker Position: 59°49.03’N, 22°19.36’E The overgrown ruins of a 120mm bunker reminded us a bit of Fort Whitman just north of Seattle.

Telephone Position: 59°48.83’N, 22°19.24’E We popped out of the woods to an open area with a small booth and an indoor phone. No dial tone though. :)

Rifle Range Position: 59°48.83’N, 22°19.23’E Looking towards the shelter of Oro’s old shooting range. The tall wall behind the targets behind the camera and the surrounding woods shelter the area, making it popular for butterflies.

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.