A Swedish ship of the line that ran aground off Suomenlinna in September 1788, was captured by the Russians and set alight, and came apart when her powder magazine exploded. What is left of her lies at about 20 metres near Helsinki, and in 2000 the Finnish Maritime Museum turned the site into an underwater park.
Also known as HMS Kronprins Gustav Adolf.
Where it is and how deep
60.0507° N, 24.9262° EPublished position for this site.
The dive
The wreck lies on the shallow north of Gråskärsbådan, the previously unknown patch of bottom the ship found while running from a Russian squadron in September 1788, southwest of Harmaja among the outer islands off Helsinki. The bottom here is around 20 metres, so the descent is short and the profile is an easy one; what the dive asks for is cold-water kit rather than careful depth planning. Take a torch.
What you find is a ship that came apart rather than a hull you can swim along. The Russians burned her where she lay and the powder magazine went up, so the site is timber and structure spread across the bottom rather than a standing wreck. Two of her cannons were lifted off in 1995, and in 2000 the Finnish Maritime Museum turned the site into an underwater park.
The wreck
- Vessel
- Kronprins Gustav Adolf
- Type
- Line-of-battle ship
- Built
- 1782
- Sunk
- 1788
- Cause
- Grounded fleeing a Russian squadron, captured and set alight; the powder magazine exploded
- Lies
- On a shallow north of Gråskärsbådan, southwest of Harmaja off Helsinki, at about 20 m
Kronprins Gustav Adolf was built in 1782 to a design by Fredrik af Chapman and served as a line-of-battle ship in the Swedish navy. On 6 September 1788, during Gustav III's war against Russia, she was running from a Russian squadron when she struck a previously unknown shallow north of Gråskärsbådan. The Russians took the grounded ship, made prisoners of her crew and set her on fire, and the powder magazine exploded. Two cannons were recovered from the wreck in 1995, and in 2000 the Finnish Maritime Museum turned the site into an underwater park.
Marine life and season
The sources we used don't single out particular species here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Fair | Fair | Good | Prime | Prime | Prime | Good | Fair | Off-season | Off-season |
Season follows Gulf of Finland: Jun–Sep is the open-water season; ice diving runs Feb–Apr, and the gulf freezes hard enough most winters to stop boat access.
Know before you go
- Cold rather than depth is the constraint: 20 metres in the northern Baltic calls for a drysuit, cold-water training and a torch, with a backup light for each diver.
- The wreck is protected archaeology and the timber is fragile after more than two centuries in the water. Stay off the structure and keep fins clear of the seabed.
Dive videos
Kronprins Gustav Adolf, 22.7.2012, 14:20 min. · Teemu Kerola on YouTube
Questions divers ask
How deep is the Kronprins Gustav Adolf?+
About 20 metres. The depth itself is undemanding, but cold matters more here than the profile does: a drysuit, cold-water training and a torch are what the dive actually requires.
Can you dive the Kronprins Gustav Adolf?+
The Finnish Maritime Museum turned the wreck into an underwater park in 2000, so the site is set up for diving visits. Check the current access terms before planning a trip: this is protected archaeology, not an open site.
Sources
- Kronprins Gustav Adolf (Finnish Wikipedia) — Wikipedia
- List of ships captured in the 18th century — Wikipedia
- Kronprins Gustav Adolf — Hylyt.net
In The Logbook
- Ice diving: how it works and where to goCold water · 12 min read
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