Jar amidst the wreck structures.

Huis te Warmelo

The wreck is located offshore in the waters of Porvoo, about 2 km west of Kallbådagrund lighthouse. The Uusimaa Centre for Economic Development, Transport, and the Environment, based on the recommendation from the Finnish Heritage Agency, designated a protected area for the wreck on June 6, 2018, under the Antiquities Act. The diameter of the protected area is 800 meters, with the wreck at its center. Diving and anchoring within the area are prohibited without permission from the Finnish Heritage Agency.

The wreck is that of a wooden-hulled sailing ship. Its total length is approximately 36 - 37 meters, and the inner width of the uppermost deck at its widest point is 8.3 meters (measurements by the Badewanne diving group in 2014). The ship had two gun decks, with a total of about 40 cannons. Some of the cannons on the port side (left side) are almost in their original positions on their carriages in the gun ports. The length of the cannons is 230 - 240 cm. There may have been cannons in three tiers at the stern, with only a few smaller cannons on the uppermost deck.

The left side (port side) of the wreck is more intact than the starboard side (right side). On the port side, there are high arches at the stern that rise above the deck level. This suggests the presence of a stern deck that extended almost to the location of the main mast. The remnants of the stern deck are indicated by the mixed structures aft of the main mast, which appear to have collapsed from the stern deck. The starboard side planking has fallen off, leaving only the lower portion of the planking intact. The planking on the left side of the deck is still in place, while the right side is more fragmented. The masts are broken. The stern transom of the vessel is almost intact up to the level of the rudder surface. At this level, the width of the stern transom is 7.5 meters (measurement: Badewanne 2014). Based on measurements, the length of the main deck of the wreck is estimated to have been about 35 meters, and its width slightly over 9 meters.

The wreck was discovered in multibeam sonar surveys by the Finnish Maritime Administration in 2002. The diving group led by Jussi Kaasinen (later known as Badewanne) first dived to the wreck in poor visibility in 2006 and observed that the wreck was a heavily armed old sailing ship. The group has documented the wreck in at least 2006, 2011, 2013, 2014, and 2016. In 2014, the group also conducted measurements. SubZone Oy has conducted fieldwork on the wreck with permission from the Finnish Heritage Agency from 2016 to 2019, to produce a 3D image.

Based on the research by Dutch history researcher Peter Swart and Finnish divers, the wreck has been identified as the Dutch warship "Huis te Warmelo," which sank in 1715. Huis te Warmelo was built in Medemblik, North Holland, on the coast of Zuiderzee, in 1708-1709. It ran aground on the Kalbådagrund shoal on August 25, 1715, while being part of a convoy escorting 200 merchant ships traveling to St. Petersburg. The convoy was returning from St. Petersburg at the time of the shipwreck.

In the fall of 2011, the Finnish Heritage Agency received reports from recreational divers about damage to the wreck site and the removal of artifacts. The Finnish Heritage Agency reported the incident to the authorities for investigation, but the perpetrator could not be identified.