The USS Pampanito is a United States Navy submarine that completed six World War II patrols in the Pacific Ocean, sinking six enemy ships and damaging four others. After the war, the Balao-class submarine returned to the San Francisco area and was decommissioned at the Mare Island Naval Shipyard but remained there in reserve. From 1960 to 1971, the ship was assigned to the shipyard’s Naval Reserve Training program. The submarine was officially retired in 1972.
Today the USS Pampanito – a National Historic Landmark – is docked at Fisherman’s Wharf in San Francisco, where it serves as a memorial and museum ship operated by the Maritime Park Association. The ship hosts over 100,000 visitors a year and is one of the most popular historic vessels in the country.
Given that brief history, you may be wondering “When was the USS Pampanito ever captured?”
The Pampanito is moved to a dry dock approximately every 7 years for routine hull inspection, maintenance, and repairs. But until now, the only as-built documentation of the submarine’s hull (as well as the rest of the ship) were scans of microfilm of the ship’s original drawings dating from 1943.
“As you can imagine, these were never truly accurate as-builts,” explains Rich Pekelney, an independent consultant and volunteer for the Maritime Park Association. For over 25 years, Pekelney has been providing hands-on work to restore the submarine. “Often, the existing drawings do not reflect the changes made to the ship, due to accidents, repairs, maintenance, or even just corrosion over the years. In addition, the original drawings are challenging to use even by trained marine architects.”
For decades Pekelney and the other Pampanito volunteers wanted to get skilled people with total stations to document the hull form when it was in dry dock. But that would be too expensive for the non-profit Maritime Park Association to undertake, and too time consuming for volunteers.
So while the Pampanito was in dry dock this fall, Pekelney arranged for a team to scan the 311-foot length of the ship’s hull. Recruiting the expertise took just a phone call. In 2015, the Autodesk REAL 2015 conference in San Francisco included an event on the Pampanito, and Pekelney got to talking with some of the Autodesk ReCap team about the Pampanito’s restoration and the lack of accurate documentation. This past summer, he called one of those Autodesk folks he met to ask if they knew of a group or company that would volunteer their time and equipment to scan the sub while it was in dry dock.
“That’s all it took,” says Pekelney. “Autodesk arranged for a crew and equipment to spend a day scanning the exterior of the submarine.” 44 scans were taken using Leica P16 and Topcon GLS-2000 scanners. In addition, 3DR used one of their UAVs to fly over the dry dock and capture aerial images that will be blended with the laser-scanned point clouds to document the top of the submarine that the scanners couldn’t see and also provide context for the surroundings. The scanning effort itself took just four hours and another hour to register the scans in ReCap. The volunteers from Autodesk are currently creating a final 3D point cloud model for the Maritime Park Association to use for its future efforts.
“Our mission is to bring maritime history to life through preservation, research, and education,” says Pekelney. “These first scans of the submarine are going to help us in all three domains.” The ReCap point cloud model will provide an accurate and current reflection of the hull to help with the design of new components that will interface seamlessly with the submarine’s historic fabric. For example, the Maritime Park Association is currently designing a new landing platform for the submarine’s ‘brow’ (the ramp that visitors use to walk on the boat.) Using the point clouds as reference, Pekelney and his team will now have an accurate basis for their design without having to take extensive measurements with a tape measure.
Moreover, researchers and modelers will have easy to access and use of shape data for the submarine that they can use in their own projects. And for education, online visitors will be able to use the 3D model for a virtual underwater tour of the submarine.
Pekelney expects that they will continue to use reality capture and scanning technology on the Pampanito. For example, he would like to have the interior of the submarine scanned to document current conditions and also use the point clouds as a fit-up reference during the repair, maintenance, or replacement of the boat’s equipment and instrumentation. And for the hull, point clouds from existing and future dry dock scans can be compared to determine exactly what has changed and assess any hull deterioration.
You can experience the ‘Capture of the USS Pampanito’ for yourself – just click here to check out the point clouds in the ReCap public gallery!