The time has finally come to
re-deck PT-305. The sheer is in place,
deck ribs are secure, the inner layer of planking laid, the covering boards are
installed and some the ridiculous eighty foot deck boards are ready for
installation. Smiles are all around as the crew, for the first time, learns how
to deck a Higgins PT boat.
The groundwork for this moment was
laid down back in 2009 when it was discovered that the deck of PT-305, and the
ribs that supported it, were completely shot. Over sixty years of wear and tear
had taken their toll on the construction. Deck ribs failed, screws corroded and
planks rotted. This resulted in a very dangerous situation- any careless
footstep on the deck would send a volunteer foot right through. Luckily the
caution and vigilance of the crew has prevented any serious deck related mishap.
The other major problem with the deterioration of the deck is structural. The
planking of a wooden boat provides the majority of the strength in the
completed vessel. A weak top deck would undermine the structural integrity of
the boat while underway; therefore, if the deck was determined to be weak it
would have to go. The crew’s worst fears were confirmed when the deck was
removed. Hoping the ribs would still be
intact and could be used, the deck was cut away around the ribs, only to reveal
that the glue in the deck ribs had failed and the ribs had delaminated,
effectively flattening the deck and rendering it structurally unsound. The ribs
were removed and the process of replacing the deck began.
This 2008 photo of a deck rib and decking
demonstrates the damage done to the original woodwork.
Many measurements had to be made,
sections of hull restored, debates started and material ordered before the deck
was laid again. This is why it took until this Saturday to begin laying the
final layer of decking.
Over the last few weeks the inner
layer of 3/” mahogany planking was laid in a diagonal pattern across the entire
length of the deck. This inner layer rests directly on the deck ribs, meaning
when you are inside of the boat this is the “roof”. While the inner layer was
being laid, the covering board was completed and Doc began production of the
top layer of deck boards. The top deck boards are 5/8” by 2 inch mahogany
planks that are spliced together to create boards up to 80 feet long. The deck
boards run fore to aft, the entire length of the boat, except for the center
section that is interrupted by the chart house and engine room hatch. Each deck
board has a rabbet cut in it on both sides for the full length. A rabbet is a
groove cut in boards to accept and overlap other boards forming a tight seal or,
in this case, it forms a groove between neighboring boards that will accept caulking.
Due to the length of the deck boards, the
crew has to route them using a special setup outside in order to create the
rabbets.
This photo shows detail of the decking. The holes will get screws, and rivets will go
on either side of the line of screws.
Caulking will fill the crevices in-between each deck plank. The center plank, wider than the, others is
known as the “king plank.”
Screwing down the deck planks is a
multi-person job. The planks have to be
perfectly aligned, and screwed into deck ribs which are not visible beneath the
inner planking.
The completed deck will be one inch
thick consisting of the inner 3/8” planking, one layer of dolfinite, one layer
of canvas, another layer of dolfinite and the final top layer of 5/8” deck
boards. The rabbets in the final deck boards will allow caulking between
boards. This entire assembly is screwed to every deck rib and riveted together
between every deck rib. Because we are just learning how to do this and there
is not a war on that needs this boat, we are taking a slower approach to
decking the boat. The entire deck will be put on dry, without the dolfinite
layers and canvas. Once the entire deck is fitted and “installed” it will be removed
by section and “finished” installed with the canvas and dolfinite.
Volunteers Harold and Ed prepare to work
with dolfinite.
In this photo you can see dolfinite spread
on top of canvas on a piece awaiting installation.
In other areas, work continues at a
fast pace. Frank’s crew working in the forepeak has completed the installation
of all side and lower hull ribs and the stairs leading into the rope locker in
the forepeak. Work on the bow should be completed in the next few weeks.
Frank and crew can be seen on the right-hand
side of this photo, hard at work on the
bow of PT-305.
The engine crew under Randy have
one Packard 4M-2500 engine ready to go. The engine looks beautiful in the
Packard colors matched from paint on original parts. Jim and Randy are working
on mounting water pumps to the engines and finalizing plans for the test stand.
One of the current engine stands will be converted to an engine test stand that
will be able to sustain one idling engine for a few hours. Because of space
restrictions within the engine room, Randy wants the engines thoroughly tested
before they are installed. This will make quite a show in the parking lot next
to the warehouse.
Propeller shaft alignment was
momentarily discussed in the last post, and this week the tedious process
continued. Because the engines and shaft need to be in almost perfect alignment
this process will take a while. One of the oldest shipyard methods for aligning
a shaft and support struts is the method that the crew has used on the two
landing craft we have restored, and is now being used on PT-305. First, the
angle of the shaft is determined. The starting and ending positions, the front
of the engine and the propeller are established. Connecting these two points
are a length of piano wire with a large weight attached to one end. This
creates a perfect line, establishing a visual marker for all of the support
struts, shaft holes and engine mounts to be measured off of. The support struts
have round holes that the propeller shaft passes through. By mounting these
struts with the piano wire centered in the middle of the shaft hole, a support
system that will hold the shaft along this line is established, thereby
creating a straight propeller shaft. This process is not as easy as it seems.
It is very difficult to determine the starting and ending positions of the
wire, the angle of the propeller shaft you want and centering the wire within
the shaft struts. There is also one major catch, being a wooden boat, as soon
as PT-305 is placed in the water the shape of the hull will change. The goal is
to get it as close as possible in the warehouse to reduce the amount of
tweaking required while the boat is in the water.
Frank, Joey and Norman at work with their
propeller shaft alignment setup. The
shaft will pass above the keel (the board in the center) and run through the
aft bulkhead of the engine room, eventually passing through the keel and out of
the boat.
Post by Josh Schick and Kali
Martin.
All photos copyright of Jane
Swaffield and Kali Martin.