profileDrive & Control

Historic hydraulics: Restoring WWII with a RexPak hydraulic power unit

Challenge: Provide more efficient and easy- to-operate solution for supplying hydraulic power to various systems such as periscope and doors on historic WWII-era submarine USS Pampanito.

Rexroth Solution: Custom-configured RexPak hydraulic power unit, provided for the restoration project

Results: • Rexroth recommended a RexPak hydraulic power unit custom-configured to meet the The historic World War II era submarine USS Pampanito at dock at Fisherman’s Wharf, Pampanito’s requirements , recently had its hydraulic systems upgraded with the installation of a • The unit includes a 71 cc Rexroth Rexroth RexPak hydraulic power unit. A10VSO axial piston pump driven by a 15 HP motor, providing a 30 GPM flow and supplying a One of the most popular attractions at Operated by the non-profit San maximum working pressure of San Francisco’s historic Fisherman’s Francisco Maritime National Park 750 psi Wharf is the World War II submarine Association (www.maritime.org), • The RexPak unit provides an easier- the USS Pampanito. Over 110,000 the Pampanito has been restored by to-operate and more efficient people visit the Pampanito annually, association volunteers to a specific replacement of a legacy system • Visitors to the Pampanito can now a Balao-class submarine which had point in time —late 1945 —to represent see the periscope being raised six combat patrols in the Pacific the height of WWII submarine and lowered, the torpedo tube War and is now a U.S. National development. This restoration effort doors open and close, and the bow Historic Landmark. included making key submarine planes operate just as they did during the ship’s service air system running, and there were safety considerations that required proper training for its operation, which usually required the assistance of a naval veteran with background in operating a pneumatic-hydraulics system. Volunteers provide virtually all the restoration, maintenance and operation work performed on the Pampanito, so keeping the pneumatic- hydraulic system well-maintained and running was problematic, limiting the times it could be operated.

A former Navy submariner who volunteers on the sub decided to find a better, simpler solution. All it took was a hand-drawn sketch on a piece of paper.

One volunteer’s passion for Charlie Butcher (right) of Manson Construction Co. and Bill McDaniel of Hydraulic the Pampanito Controls Inc. pose with the complete RexPak hydraulic power unit dockside. Charlie Butcher is the Equipment Manager for Northern California at systems fully functional, so visitors “As much as possible, we try to Manson Construction Co. (Seattle, can see the periscope being raised utilize 1940s-era technology for the WA www.mansonconstruction.com), and lowered, and the torpedo doors restorations,” said Richard Pekelney, one of the nation’s leading heavy civil being opened and closed. secretary on the association’s board marine construction and dredging of trustees. “However, for some companies. He’s also a retired U.S. To accomplish this goal, the Pampanito systems, we find it’s more effective for Navy Master Chief Petty Officer and needed efficiently functioning us to utilize modern equipment, like submariner with 30 years of service hydraulics—and Bosch Rexroth the Rexroth RexPak hydraulic unit.” in the U.S. Navy and Navy Reserves. (Charlotte, NC www.boschrexroth-us. Manson Construction has long com) was glad to assist, contributing There are three hydraulics-powered supported the restoration and historic a custom-configured RexPak hydraulic ship systems that have been restored operation activities of the Pampanito power unit to help bring the ship’s to working condition: the external bow as a by taking care of systems to life. planes used in navigating the ship, the moorings and other maintenance. torpedo tube doors, and the ship’s Working memorial to the Pacific War periscope. Until recently, hydraulic “Initially I wanted to find a simple The association took possession of power was supplied to this equipment pressure-compensated hydraulic the boat in 1976 and since then, the by the boat’s original “air over pump to raise the periscope,” said Pampanito has undergone multiple hydraulics” unit: high-pressure air is Butcher. In discussions with Pekelney, restoration projects, including four pumped into a hydraulic accumulator, it became clear that being able to separate dry-dock visits. Almost all of creating the necessary hydraulic oil open the torpedo tube doors and the ship’s systems have been restored; pressure to operate this equipment. move the boat’s bow planes was a as a result, much of the onboard priority as well, which would make it electrical and mechanical equipment This air over hydraulics system easier to perform hull maintenance is now functional. presented some difficulties. It took up when the submarine goes into to a full day to get the high pressure dry-dock. A new unit to supply hydraulic power RexPak offers the perfect fit As Butcher and Pekelney refined their McDaniel worked with Bosch Rexroth hydraulics requirements, Butcher to create the Pampanito’s RexPak contacted Bill McDaniel, Account configuration. They used the RexPak Manager at Hydraulic Controls, Inc. Design Engine, an online configuration (Emeryville, CA www.hydraulic- tool that captures the key data needed controls.com), one of the leading to configure a RexPak hydraulic suppliers of hydraulic components in power unit. “It was extremely helpful the Pacific Southwest and a Bosch in guiding us to determine the right Rexroth distributor partner. configuration to provide the hydraulic pressure required to operate the That’s where the sketch came in. “We boat’s equipment,” McDaniel said. knew we would need a larger solution “It gave us all the right questions to than just a simple pump,” Butcher ask—the weight of the bow planes and said. “I made a little design sketch, the periscope, how much hydraulic since I knew the boat’s hydraulic fluid is accumulated from the forward systems, and sent it off to everybody engine room, the distances between to see what we could work out.” the hydraulic power unit and the equipment it will operate, and According to McDaniel, the sketch so forth.”

Butcher provided, along with his The RexPak unit’s compact design made descriptions of the boat’s hydraulics it well-suited for the tight confines in the For the Pampanito, the RexPak is Pampanito’s engineering spaces; it was requirements, led him to consider configured with a 71 cc Rexroth also easy to integrate into the WWII era several Rexroth options. ”At first, equipment on the ship. A10VSO axial piston pump driven we looked at using a closed-coupled by a 15 HP motor, providing a 30 motor package,” he said. “But after Although each RexPak solution is GPM flow and supplying a maximum consulting with Rexroth, we decided unique, units are built from readily working pressure of 750 psi. The unit that the RexPak hydraulic unit was available Rexroth hydraulics products includes an 80-gallon hydraulic fluid a better option. We could supply a and can be designed, configured and reservoir, a mounted inline relief valve, complete package, test it, make sure delivered in as little as six weeks. pressure gauge and both return and everything was good to go, and ship pressure filters. them the whole system.” According to Butcher, this The RexPak hydraulic power unit configuration provides sufficient bridges the gap from standard market hydraulic power to demonstrate how products to custom-engineered the different pieces of equipment on power units. Designed for a variety the boat work and allows the 2,000- of applications that require hydraulic pound periscope to be raised and power up to 75 horsepower (HP) and lowered at its original speed. 65 gallon per minute flow (GPM), with operating pressures to 3200 pounds Each piece of equipment being per square inch (PSI), each RexPak demonstrated is operated system is custom-configured from independently, so the RexPak does a core set of components: motor, The RexPak hydraulic power unit, installed not have to supply hydraulic power to pump, fluid reservoir and associated in the engine room, supplies hydraulic all three systems simultaneously. And pressure to multiple pieces of the ship’s control valves. since the RexPak has been integrated equipment, including the periscope, bow planes and torpedo tube doors. into the boat’s existing hydraulic lines, the boat’s original controls advantage of existing bolts and holes on the bridge and in the engine to support the RexPak pump, motor and torpedo rooms can be used to controller, hydraulic fluid filters and demonstrate how the equipment other system elements. originally operated. Using the RexPak unit will help the According to McDaniel, the RexPak Pampanito save energy, since it Design Engine system also helps takes much less power, compared to Butcher and his fellow volunteers with running the high-pressure pneumatic detailed documentation. “It provides air compressor. And the system an engineered drawing and a detailed can be easily broken down into its datasheet of every component, so constituent parts and carried piece by we could take the original sketch and piece below decks, then reassembled. make it into something formal in a According to Butcher, this helped very short period of time.” simplify installation.

Donations support The RexPak unit is also much easier hydraulics restoration to operate, which means many more Butcher believed the RexPak unit volunteers, not just veterans, can be

would work well in the Pampanito trained on it, so the periscope and With the RexPak hydraulic power unit, due to its modularity and ease of other systems can be demonstrated hydraulic power can be more easily and efficiently supplied to the submarine’s integration with the boat’s existing more frequently to visitors eager to systems, so that visitors to the Pampanito hydraulics piping and controls—even see the authentic submarine. have the opportunity to experience how though much of that equipment is the periscope works. decades old. The team was able The valuable time and effort to get to install the Rexroth equipment in the right solution for the Pampanito’s such a way that the ship’s original hydraulic restoration was all donated— The 30-year Navy man and former hydraulics plant can still be operated as was the RexPak unit itself. Bosch submariner appreciates how the with the modern technology, to retain Rexroth’s distributor partner Hydraulic RexPak makes some of the more the museum ship’s authenticity. Controls Inc. donated the system, popular Pampanito sub equipment as well as their time. And, of course, operational. “Everyone wants to look “We wanted to keep the functionality Charlie Butcher has been donating out the periscope,” said Butcher. of the original system,” he said. “We all his time, along with other Manson “From the young people to the had to install some special flanges and Construction Co. technicians, World War II submarine vets and their mounting brackets in some places, to configure brackets and other wives, they all like to see things in but in most cases you can’t even tell supporting materials to complete operation, so we know the visitors will that the system’s there.” Technicians the project. really appreciate it.” were able to fabricate brackets to take

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