Construction: Weeks 9 to 12 - Bulkheads & Tankage

Week 9 marked the start of bulkhead and tankage installation.  The hull lay-up and stringer system have been completed.

Bulkheads divide the boat into compartments and provide structural rigidity for the hull system.  Their installation precedes removing the hull from the mold.  In the photo below, you can see tankage at the stern and one bulkhead lying in the bilge awaiting installation.

Week 9.  Bulkhead and tanks awaiting installation

The diagram photos below show the layout of the main deck and the accommodation decks.  The bulkheads can be understood from expanding the photo and looking at the lower one.  Moving from the stern forward, the bulkheads delineate the lazarette, the engine room, hanging lockers, master stateroom with en suite head, stairwell (to starboard), washer dryer space and third stateroom (to port), forward head (to starboard), VIP stateroom and bulkhead separating the V-berth from the chain locker.

CAD Diagrams of main and accommodation decks

The week 10 photos indicated considerable progress. That said, it was not initially clear to me what each represented so I asked Jeff Druek for notatations to help me understand what each represents. 
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Week 10.  View of newly installed bulkheads prior to being veneered

Week 10.  Rough engine room and lazarette bulkheads.  ER refers to engine room

Week 12.  Shows veneered lazarette bulkhead and two 500 gallon fuel tanks installed in engine room

The bulkheads in the engine room forward and aft are watertight and heavily insulated.  They are fiberglassed (i.e., tabbed) into the hull sides with mat and woven roven to produce a watertight seal. 

Below is a cross section photo showing bulkhead construction.  Notice the pegboard.  Working from the pegboard forward there are the following layers:

• Pegboard (Engine side)
• Foam to deaden sound
• Plywood
• Layer of lead
• Plywood
• Foam
• Plywood
• Veneer (Master Stateroom side)

This structure is also used on the engine room ceiling, which sits below the salon.  This is one of the reasons why the sound level is very low in the salon and pilot house.  The engine room is completely enclosed with sound deadening materials.

Engine Room Bulkhead and Ceiling Construction

Week 10. Thruster tubes for the hydraulic bow thruster (under V-berth)

Week 10.  The 100 gallon black water tank is the boat's hold tank for human waste

Week 12.  The 100 gallon holding tank installed

Week 10.  The water tank shown in the next photo will be installed here

Week 10. 200 gallon water tank awaiting installation



Week 12. 200 gallon water tank installed  Forward head is to starboard on your left

A word about fuel tanks.  Outer Reef's fuel tanks are fabricated of aircraft grade aluminum and where the fuel lines mate to the tanks they are welded.  Many other builder use fiberglass tanks with fuel lines bolted to the fiberglass. Bolting fuel lines to fiberglass can lead to leaks and diesel odors onboard. Over time fiberglass tanks can also begin to flake and cause fuel line blockages. 


Week 12.  Close-up of two 500 gallon aluminum fuel tanks

I experienced flaking in fiberglass tanks on a 1977 38 Hatteras Flybridge Double Cabin (FBDC) that I bought in 1984 (see link below for a photo).  On a cruise from Michigan City Indiana to Mackinac Island Michigan we experienced surging and engine loss on both engines.  The problem was ultimately (unfortunately after trying several other expensive solutions) diagnosed to fiberglass flakes in the tanks that were, under certain circumstances, restricting fuel flow by blocking the fuel lines to the engine.  The problem was solved.  The boat was sold in 1976 (for more than I paid for it - the only time this has occurred).

http://www.powerboatguide.com/Free_Access_files/Hatteras%2038%20Double%20Cabin.pdf

Written by Les.