TITLE 46 - SHIPPING

CHAPTER I - COAST GUARD, DEPARTMENT OF HOMELAND SECURITY

SUBCHAPTER T - SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS)

PART 178 - INTACT STABILITY AND SEAWORTHINESS

subpart d - DRAINAGE OF WEATHER DECKS

178.450 - Calculation of drainage area for cockpit and well deck vessels.

  (a) The drainage area required on a vessel must be computed using the following formula: For protected waters required drainage = .1 Basic Drainage For partially protected waters required drainage = .5 Basis Drainage For exposed waters required drainage = Basic Drainage where: Basic Drainage area in centimeters 2 = 4389.12 [(Recess Volume Recess Ratio) + (Weather Deck Volume Weather Deck Ratio)]; or Basic Drainage area in inch 2 = (Recess Volume Recess Ratio) + (Weather Deck Volume Weather Deck Ratio) Recess Volume = (BR DR) VR BR=average height in centimeters (feet) of the bulwark above the well deck or cockpit deck; DR=total deck area of the cockpit or well deck in the after 2/3 of the vessel length (LOD) measured in centimeters2 (feet2).

VR=volume of any weather tight structure below the bulwark of the well deck or cockpit deck.

Recess Ratio = LR / LC LR=the length of the recess in the after 2/3 vessel length (LOD).

LC= 2/3 vessel length (LOD).

Weather Deck Volume = (BD DD) VS BD=average height in centimeters (feet) of the bulwark above the weather deck; DD=total deck area of the weather deck adjacent to bulwarks but not in way of the cockpit or well deck in the after 2/3 of the vessel length (LOD) measured in centimenters2 (feet2).

VS=volume of any weather tight superstructure below the bulwark on the weather deck located within DD.

Weather Deck Ratio = LD / LC LD=the length of the weather deck bulwark in the after 2/3 of the vessel length (LOD).

LC= 2/3 vessel length (LOD).

  (b) Vessels with bulwarks in the forward part of the vessel shall not form a well with the deckhouse which retains water.

[CGD 85080, 61 FR 966, Jan. 10, 1996; 61 FR 20557, May 7, 1996]