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Tanks and Liners for Immediate Storage of Waterlogged Collections

Purpose

When a runaway barge collided with navigation markers on the Nanticoke River last spring, the Coast Guard called the resulting debris a hazard to the commercial waterway and ordered Maryland State Highways Association to remove the timbers.  When the divers started to haul up the timbers, it was a surprise to find a 30 foot section of a ship’s keel (Image 1). Suddenly, it was a rush to salvage as many timbers before the disturbed wreck site was washed out to the Chesapeake Bay.  With no plans for funding, staff, excavation, curation, conservation, viability surveys etc., an above ground pool with a custom made bubbler system became a very quick, inexpensive, and effective temporary storage solution.

Author(s)

Nichole M. Doub
Maryland Archaeological Conservation Laboratory
Saint Leonard, MD 20685
410-586-8577
n.doub@maryland.gov
www.jefpat.org/mac_lab.html

Photo Credits: MAC Lab

Publication: 2017

 

Image 1: Recovery of ship fragments from the Nanticoke River.

 

Description

Due to the short reaction time prescribed by this emergency salvage, the archaeological and conservation teams scrambled to find a large container to store the ship timbers for an undetermined period of time, while still allowing access to researchers.  A ready-made above ground recreational pool fulfilled the immediate requirements.

Image 2: Construction and loading timbers into the above ground pool.

 The ship fragments were discovered in April and with the warm weather, biological growth became a serious issue. While a viability survey was in progress, the final destination of the timbers remained in question.  One option under discussion, was the reburial of the timbers in a local body of water.  This prevented conservation staff from introducing a biocide to the container that would potential contaminate any future burial environment, and other methods were needed to mitigate biological growth.  The pool had the added benefit of having built in attachment points so that staff was able to hook up a filtration pump.   And a lattice of perforated PVC pipe was built to span the surface of the pool.

Image 3: Pool with bubbler system.

 This was attached to a submersible sump pump that both aided in the circulation of the water and agitated the surface to prevent the breeding of mosquitos and other pests.  It also has the added benefit of preventing ice formation in the winter months.

Materials, Tools & Supplies

  • 1 ½” PVC pipe
  • PVC cement
  • ¾ HP submersible sump pump
  • Electric drill
  • 5/8″ drill bit
  • Empty soda bottles
  • Cable ties

Construction

  1. Construction of the bubbler system consisted of cutting length of PVC pipe to fit the dimensions of the pool and joining those using PVC connectors and PVC cement, making sure to leave one end for attachment to the pump and capping the other end.
  2. Using a 5/8 drill bit, holes were made along the top surface of the frame.
  3. In order for the frame to float, 2 liter soda bottles were attached at intervals using cable ties. To increase the power of the jets, the frame should be positioned closer to the surface of the water. To decrease power, allow the frame to be submerged several inches. 
  4. Finally the frame was connected to the submersible pump using a length of PVC pipe and a 90-degree elbow.

Comments

The MAC Lab has many occasions to use large tanks for storing wet archaeological materials, both on-site and in our laboratory facility.  Our preferred method for temporarily storing large quantities of water on archaeological and construction sites is folding frame tanks.

Image 4: Folding frame tank filled on-site by a local fire department.

 They are light weight, self-supporting and allow for quick and easy draining.  Our favorite brand is provided by Husky (www.huskeyportable.com).  When in the lab, our tanks also have to be able to withstand the properties of any chemicals we might use.  We choose to build wood tanks that can be fitted with removable liners.

Image 5: Lined wood tank with bubbler system.

 Our liners are provided by FlexiLiner (www.flexi-liner.com).  In communication with their chemists, we are able to find suitable liner materials that specifically meet our conservation needs and are custom sized to fit each tank.

Keywords

waterlogged wood, temporary archaeological storage tank liner

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