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Apr 2009 - Mar 2009 Charles W. Morgan Restoration Updates
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MORGAN: Approximately 1 inch of the CWM's 11 inch hog has been removed by gravity force in three cycles of removing and replacing softwood "crush blocks" and realigning the underpinning hardwood keel blocks. This process will be suspended for the moment while the shipwrights measure and assess the overall movement of the hull by means of a laser surveying system. Although movement to date has been relatively easy, the fact of this ease gives some clue as to the overall condition of the hull, which we know is weak.
Three small ceiling planks have been removed. Their condition is no better nor is it worse than expected and are clearly in need of replacing.
The shrink wrap cover is being installed this week.
The shipwrights are still working on developing an efficient method to keep the hull wet. The rain this past week has week helped. Additional applications of Bora-Care and AnchorSeal have been made to the starboard side, which has the benefit of locking in moisture because of their white reflective nature. The shipyard is still looking for an efficient misting nozzle which will spray fresh water on the hull. Ideally salt water is preferred but in previous renovations it was found that use of salt water created system maintenance problems. Instead the shipwrights will spread ample quantities of salt and spray a brine solution.
More live oak was delivered to the rear of the south parking lot today.
MORGAN: The shipwrights are starting to let the hog in the MORGAN to drop by natural gravity force. (Hogging is the tendency of vessels to sag at the stem and stern ends due to the less buoyant nature of these parts of the vessel as compared to the amidships. Hogging is manifested by the curved shape of the keel.) The process is complicated. Selected keel blocks are configured to have a softwood "crush" block between the hardwood blocks and the bottom of the false keel. As the hull drops, the softwood crush blocks are pinched and are removed with a chainsaw. This process will be repeated several times until approximately ½ of the MORGAN's 9 5/8s inch hog is eliminated. Further evidence of movement is the need to back off on the screw jacks at the stanchions. This is necessary to ensure equal distribution of weight on the hull supports.
There are several keyholes which have been revealed in the false keel. (The false keel is the bottom most portion of the keel. It is relatively new whereas the full keel to which the frames are attached is original construction.) The key holes permit the scarf fabrication of the false keel to expand lengthwise. (There is a good depiction of scarf fabrication in the THAMES keel exhibit.) Meanwhile, as the keel is lengthening, the main deck is being forced to shorten. The shipwrights will "reef" out some of the butt joints in the main deck to enable this.
The longitudinal strength of the MORGAN's hull is compromised by rotten planking and the poor condition of the ceiling. Both the planking and the ceiling (which is original to the vessel), are critical to the vessel's strength. The natural stresses in the hull must be balanced slowly and as the desired hull form takes shape, the shipwrights will replace key planking and the ceiling. It's a three year process and a complicated feat of workmanship.
The shipwrights have a varied selection of fasteners that they will work with, ranging from a wooden trunnel (short for tree nail) to a metal rod to various sizes and materials of metal "spikes." Each is used for a specific purpose. For instance, planks are fastened initially with metal "butt spikes" which secure the planks ends to the framing to lock in the shape of the bend. Metal hanging spikes hang the plank in place. Finally trunnels are driven (paired with a hanging spike) to secure the plank to the frame. The trunnel has a club like shape and is allowed to dry thoroughly. When installed, one end is split and wedged. This end is driven to the bottom of a predrilled hole. The driving end is cut flush with the plank and also wedged. When the vessel becomes wet, the trunnel expands creating a very tight fit thus enhancing the strength of the hull.
An exhibit showing the various types of fasteners will be prepared for the Shipyard Gallery. The type of material used in metal fasteners is very important. Bronze or copper resists corrosion, whereas steel deteriorates quite quickly. The type of metal used often determines the life of the vessel. Older oyster skiffs in the Chesapeake have survived well past their newer sisters, because non-steel fasteners were used in their construction.
In order to document all changes in the hull, no matter how slight, the Research and Documentation staff will be taking measurements using an electronic measuring device. The first step is to install small reflective targets that can be shot with infrared light rays; the rays bounce back to the machine for a very accurate measurement. There will be approximately 130 of these targets on each side of the hull.
The expansion drawing of the ceiling is completed for one side. The final two brackets for the hull supports have been installed on the starboard side aft.
The Research and Documentation staff has been researching the archives for photographs from the 1970s restoration so that the current team of shipwrights can see how previous work was done, and how specific problems were addressed.
The five brackets for the stanchion and jack system have been installed on the port side and two on the starboard side. The shipwrights and marine engineers are considering the addition of two more brackets, one on each side, of a slightly different design toward the stern. No decision has been made. This is a good example of some of the challenges that face the shipwrights. As the work progresses and in spite of well thought out engineering solutions, new facts emerge and alterations to plan must be made or considered.
The sheathing is almost off of the port side. Removal has proven to be an onerous and dirty task. Not only does the copper sheathing and wood need to be removed, the tar between the sheathing and the planking has to be scraped, allowed to dry and scraped again. All staff and volunteers will work on the starboard side next week and, hopefully, this phase will be finished. The good news is that the fine lines of the hull planking and hull shape are now revealed and a more thorough inspection of the planking can be undertaken.
Several of the newly exposed planks show signs of obvious rot while others seem quite solid. This is the tricky part. The shipwrights know that much of the ceiling and framing is rotten but until the planking is opened from the inside and each plank sounded, we won't know the full extent of the project ahead.
The shipwrights are seeking a design for an irrigation system to keep the hull wet. In the next few weeks lawn sprinkler and greenhouse watering system providers will be visiting the Museum to offer their expertise to help keep our 168-year-old artifact wet while she is out of the water and in danger of drying out. In the interim, shipwrights are spraying the interior by means of a backpack sprayer using a brine solution.
This brings up an interesting fact. As built and until the 1950s, the space between the framing, planking and ceiling was filled with salt. Shelves were placed in these spaces to prevent the salt from settling into the bilge. The salt helped absorb fresh water which leaked into the hull cavities. In turn, the resulting solution seeped into the wood and helped preserve it.
The shrink wrap cover will be installed in about three weeks, once the weather allows.
OTHER SHIPYARD NEWS
- Sabino has been painted and inspected by the Coast Guard and will be re-launched early next week.
- Necessity is currently in the paint shed.
- The Conrad's mizzen is in the shed. The plan is to re-step her lowers between April 8 and 15.
Installation of the brackets to hold the hull stanchions commenced this past week. The hull stanchions will support the vessel while many structural parts are removed to be replaced. The brackets are 3 X 3 foot steel crosses bolted through the hull to washer plates on the interior of the hull. They are strategically located five to a side where there are both hanging and standing knees. In addition, two stanchions support the stern and a single one supports the stem.
Final measurements of the ceiling are complete and are being loaded into a computer system. This has proven to be a tedious but critical task and one that goes unseen to the visitor.
A preliminary inspection of the hull has revealed not only a nine inch hog in the keel but the starboard quarter is drooping. Once the stanchion and jack system (the jacks will be at the foot of each stanchion) is fully in place, the shipwrights will start dismantling and replacing planking, ceiling and framing. This process will require delicate balance, as pieces are removed, the hull will become more flexible. This permits the shipwrights to allow the hull to settle into more of its original shape. Then new material will be installed to give rigidity and strength. This procedure will be repeated several times until the damaged areas and the hull's shape are restored.
Interesting fact, restoration work is expensive. Each plank or other piece of wood, averaging 8 feet in length, will cost approximately $1,000 for the materials and $1,200 for labor. This is why we need those contributions! <Donate Now>
The Charles W. Morgan is taking on a dramatic new look. Framing for the shrink wrap cover is almost complete and the shrink wrap will be installed on the next calm day. Although the cover will be placed over the entire deck, there will be ample provision for personnel, visitor and materials access. The cover design will also provide for ventilation in the summer and viewing beyond the bulwarks.
The copper sheathing has been removed from the port side, numbered, photographed and bundled for storage. It came off easily and is in good shape, so will be reinstalled once the restoration is finished. Normally a vessel like the Charles W. Morgan would have had copper sheathing over the entirety of her underwater hull. The Museum only installed copper sheathing at the waterline to permit easier inspection of the bottom.
Shipyard workers have commenced the removal of soft wood sheathing covering the planking. This removal has revealed a tarred felt liner between the sheathing and the planking. This barrier provided another protection against water borne shipworms and similar "pests." From the outside/in, therefore, the ship's hull would have copper sheathing, soft wood sheathing, tarred felt, wood planking, framing and ceiling.
The Charles W. Morgan has been retopped several times by the Museum while in our ownership. This restoration will attack the below waterline amidships planking for the first time since the Museum acquired her. Previous work on the underwater hull had focused on both ends. This newest work is particularly important as it will restore water tightness and longitudinal strength amidships.
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