Strafford Morss, Preservation Engineer
Monday, September 16, 2002

Introduction: Most maintenance does not require a shipyard. Outside contractors can and will come to you. However many of the fundamental problems now experienced by ships can be traced directly back to the decisions made by the new operators when the ship was transferred from the Navy.

Berthing Techniques

Ships set on the Bottom

Original berthing concerns for a museum ship (TEXAS) consisted of placing the ship outside the navigation channel and keeping her in place.
o- Transfer of TEXAS was delayed nearly two years while Houston figured out how this was to be done.
o- In 1948, TEXAS was placed in a dredged out slip and put on the bottom. Minimal shore side facilities were required to hold her. NORTH CAROLINA followed in 1961 and ALABAMA in 1964. YORKTOWN was set on the bottom in the early seventies. LEXINGTON was the last to employ this system in 1992.

Ships Berthed Afloat

A major concern of ships berthed afloat is that they stay at their berth in a 100 year storm. This often requires construction of substantial, expensive structures, ashore or in the water. The vessel moorings have to withstand forces generated by the wind working on the exposed above water surface area. A light (high in the water, more surface area) donation ship is harder to hold than when she was loaded in service. Displacement is not a factor until she starts to move.

(The wind loading force a ship is required to resist directly varies with the square of the wind velocity in mph (not knots). The force generated at 100 mph is 100 times more than at 10 mph, and twice more than at 70 mph. NAVSEA has developed wind surface areas, broadside and bow on, for most Naval vessels in several loading conditions,)

In 1965, MASSACHUSETTS was temporarily berthed at Fall River, creating a navigation hazard as her stern extended 180 feet into the channel. In 1968, the ship was moored to state constructed mooring islands parallel to the shore, afloat, and formed a breakwater for a protected cove between the pier and shore.

OLYMPIA, INTREPID, HORNET, SALEM, MISSOURI, and NEW JERSEY are moored afloat. Real Problems

TEXAS and ALABAMA have experienced severe hull leakage, structural degradation, and documented oil releases directly attributable to their original mooring systems.

The hulls on all ships set aground are attacked simultaneously 24/7 in at least five directions:

  • wind-water line corrosion;
  • external galvanic corrosion from dissimilar metals;
  • the extraordinarily erosive effect over time of mud/sand particles rubbing the hull plate thin or through;
  • internal galvanic corrosion from dissimilar metals;
  • structural degradation resulting from the effects of anaerobic bacteria in combination with water, remaining fuel oil and results in sulfuric acid. The acid destroys internal structure, interconnecting piping, spreads problems throughout the ship, and eventually external to the ship.

Experience with TEXAS and ALABAMA have caused NAVSEA to adopt more stringent berthing requirements for new donation ships. Current NAVSEA mooring policy: Afloat berthing depth at Mean Low Water of 2 feet below (current) maximum navigation draft (ship trim, propellers, sonar domes, etc.)

Current Conditions and Prognoses

o-TEXAS returned from a massive stabilization effort in shipyard in 1990. Moored afloat for $2.5 million, TPWD is actively planning for a maintenance docking in the next several years.
o- ALABAMA will remain in a life-threatening condition even upon completion of the last of 3 Federally funded operations, totaling $11 million.
o- NORTH CAROLINA, YORKTOWN, and LEXINGTON berthed on the bottom, are guaranteed a very dark not-so-distant future unless major changes (extremely costly expenditures) are made at each ship.
o- STEWART and CAVALLA have similar structural problems at Sea Wolf Park. Their fundamental problem remains that Galveston County Parks Department has never had adequate funding, or desire, to maintain the vessels.

o- SUCCESS STORY: KIDD used foresight and imagination to use the rise and fall of the Mississippi River as impetus to create a self-dry docking situation for six months a year. TEXAS took inspiration from KIDD's system for her current afloat mooring system.

o- MASSACHUSETTS and LIONFISH dry docked in 1998-99 for $9.5 million. The battleship docking was a straight stabilization effort, but without the nasty surprises presented by the submarine. LIONFISH will require future attention, and we watch the draft marks every day. It is when, not if.

Fleet Submarines

o- SUCCESS STORIES: Part of ALABAMA'S federal money was used to place DRUM on dry land. This is a spectacular achievement. A watertight sheet-pile cofferdam was constructed around DRUM and extended on shore. On the shore keel blocks were constructed within the cofferdam. The cofferdam was filled above the surrounding water level, the DRUM floated and placed over the new keel blocks. De-watering the cofferdam was similar to dry docking the ship. With the cofferdam removed DRUM is safely on shore and awaits the pleasure of the Battleship Commission.

o- Far-sighted planning provided ALBACORE with an initial dry berth arrangement. Fleet submarines have three major preservation concerns:

  • Bow and stern free flooding fairwater structures around the bronze torpedo tube muzzles
  • Preservation of the saddle area under the superstructure deck where water collects in the pockets formed by the juncture of the port and starboard ballast tanks to the pressure hull. Tank vents, air intakes and the like take up much of the free space below the superstructure deck, limiting access.
  • Ballast tank structure at the wind water line and the sixty plus (67 on SS-298) flooding ports that are blanked along the keel line.
The problems with the mild steel bow and stern structures center around the massive dissimilar metal concentration of the torpedo tubes, pressure hull ends. Impressed current cathodic protection will not extend inside the free flooding structures. On LIONFISH the solution has been hang 4-23 # strap zinc plates welded together to form a single assembly at either free flooding end of the vessel. These submerged assemblies are electrically connected by a lead secured to one of the manhole cover studs. Experience has shown about half of the zinc weight is used every twelve months at each end of the vessel.

We have also conclusively demonstrated that 92 # of zinc hanging in the water without the electrical connection remains as good as new. AS always: never assume your people understand what you are trying to accomplish. Explain the project in painful detail and listen to your people's input.

The tank top problem is cramped and labor intensive, but seldom addressed. Some suggestions:

o- Do not use alkyd primers and paints. These coatings are not for immersion use (pocketed water) as large amounts of water vapor are transmitted through the coating to the steel. The substrate will corrode even while the coating looks reasonable on the surface.
o- Catalyzed (two part) epoxies are better, much lower vapor transmission..
o- Do not fill the saddle areas with concrete to make the water shed off. Water will shed, but concrete is a hard sponge. Major corrosion damage beneath the concrete will occur and be hidden from view.
o- A roof-style water-shed placed under the deck but over the gear below, has been proposed. It needs to be stiff enough to hold its shape. I am not sure there is adequate clearance below the deck near the sail to allow this to work.

Ballast tanks:

Plating thickness varies widely on the boat.

Thin skin ships and Fleet submarines afloat can be heeled to address preservation and/or steel work issues at the wind/wateriine. The offshore oil industry is fond of the wear doubler. Plastics can also be used. Belzona and Red Hand (International Paint) products come to mind. Competent workers are important for surface preparation, including chloride decontamination, and coating application.

Doublers and/or plastic coatings are always temporary. The question is which is more temporary: the doublers and/or coatings or the ship's permanent structure.

Impressed Current Cathodic Protection

NAVSEA requires an impressed current cathodic protection (ICP) system be installed on new donation ships as soon as possible. ICP minimizes underwater hull steel corrosion.

o- MASSACHUSETTS installed HNSA's first (I believe) impressed current hull protection system in 1976. It was essentially inoperative from 1986 to 1996. Significantly upgraded, the system has been operational since 1996.

Major limitations are:

  • Partial protection of wind/water line to about 4-feet below the surface. Tidal range enlarges the problem for a ship on the bottom.
  • Openings into the hull are protected no more than 2-pipe diameters into the interior. Free flooding spaces on Fleet Submarines are not protected.
  • ICP annual inspection and maintenance (preferably by a reputable professional) is a must. Less than 1/2 volt difference exists between not being effective and removing all existing coatings off the underwater body.
  • ICP does not protect against physical erosion, i.e., sand, but will help protect the freshly exposed base material.
  • Does not make an underwater structure better than before ICP was installed.
  • Ship's underwater configuration can shield areas from protection. This has to be taken into account during system design and before the final underwater anode locations are settled. BB-59 and 60 are particularly difficult in this area.

Electrical Power Factor

General. A substantial portion of the monthly electric bill hides in the "Demand Charge"; which forms parts of both the generation and transmission charges. Demand is related to electrical power factor, a charge being made when power factor drops below 0.9. Power Factor is calculated as the ratio of KW to KVA. PF=KW/KVA.

Demand Charges can total nearly $2K in a high usage month.

WWII US ships were designed for 440-450 volt alternating current with a 0.8 power factor. A low power factor results in increased current draw (amperage) for rotating equipment. Modern equipment is designed for 0.9 PF. At BB-59, we currently experience a 0.7 PF in the summer. Eventually both newer and older motors burn out, usually newer first, resulting in unexpected repair bills.

New electric generating facilities are extremely expensive. The electric company will design, but you pay for equipment and installation, the necessary changes to improve power factor, as it delays the need for new generation. Capacitors can be added to the shore connection to improve PF. A 500 amp service can be upgraded in Fall River to remain mostly above 0.9 PF for $15-20K. An improvement in PF would result in some amperage reduction, helping to reduce monthly power costs.


Electrical switchboards are very substantial structures. When they do not function, the historic ship is out of business, dead.

Conductor connections in back of switchboards deteriorate, getting dirty and loosening up. It is very worthwhile (about every 5-years, not 52 or 26 as at BB-59 and DD-850) to clean and tighten the boards. This requires shutting the ship down and doing the work with knowledgeable people. It is not a complete overhaul as some circuits are more important than others. In the final analysis, a clean board should transmit power and not absorb power as heat bridging poor connections.

A Final Thought

It costs money to belong to HNSA. Maximize your benefit by utilizing HNSA experience to help get a handle on problems. It makes no sense to be proud, or to put your head in the silt.

Call Chan Zucker and find out who might be experiencing similar type problems. A team approach is always better.

Jim Sergeant, at ALBACORE, has been extremely helpful to me on several occasions.

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