San Francisco Maru

“Plan the dive; dive the wreck; wreck the plan!”

- A fellow diver in Truk Lagoon, hopefully joking

A tank on the deck of San Francisco Maru. Photo by
Robert De Jongh.

Friends, today I completed my deepest dive yet! It was on the shipwreck San Francisco Maru, which rests at the bottom of Truk Lagoon. It was a fascinating wreck.

We started by swimming down the mooring line, a thick rope attached to the wreck amidships with a float at the surface. Immediately, I was struck by the presence of two tanks on the deck of the ship. Yes, tanks. They rested on an incline on the sloping upper deck of the ship, covered in a thick layer of sediment. They were smaller than I expected, but still menacing.

Through the metallic slats in the upper deck, I could see into the hold below. An old truck lay at the bottom, its grill and windshield clogged with brown silt. We swam down into the hold to have a look, then emerged a few minutes later and continued toward the bow of the ship. In the adjacent hold, there were numerous metallic spheres – beach mines. I paid special attention to my buoyancy and avoided tapping any of them, but Carl assured me the detonators were stored separately and were stable underwater. The mines were very cool to see.

Invertebrates on the bow gun on the San Francisco Maru.
Photo by Robert De Jongh.

Back on the deck of the ship, we made one last stop at the bow gun. Similar to most wrecks in Truk Lagoon, the bow gun was colonized by sessile invertebrates, but the community was a little different on the San Francisco Maru. The deep wreck had a thinner population of benthic invertebrates, with fewer corals and more sponges. In fact, the most common species I remember from the San Francisco Maru was a purple pipe-shaped sponge. It grew in clusters of 3 – 4, which dotted the upper surface of the wreck. Long, stringy green wire corals were also very common.

The depth of the wreck meant I got just 22 minutes on bottom before we needed to head back up the mooring line, but those few minutes were amazing. I was glad to see the wreck of the San Francisco Maru.