General Boat Crew Sign Offs

Explain the benefits associated with the different levels of hypothermia protective garments and how they relate to Tables 3-1 and 3-2 of the Rescue and Survival Systems Manual.

They insulate body heat and provide a seal from water.

1. Work uniform type III PFD & Boat Crew Survival Vest- Water Temp 60F- Air Temp 30F

2. Anti Exposure Coveralls & Boat Crew Survival Vest- Water Temp 50-60F- Air Temp 50F

3.. Dry suit w/ Layers, Survival vest, and Neoprene Hood- Water Temp below 50F- Air Temp 50F & Below

Explain the factors that accelerate the onset of hypothermia.

Decreased body fatness: Less of a barrier.Decreased clothing protection: More layers if more proctection.Increased wetness: Water conducts heat away from skin surface.Decreased metabolic capacity: Body will begin to lose ability to metabolize nutrients, leading to loss of heating fuel, leading to loss of heat production.Injury: Affects ability to maintain proper heat production.

Describe the preventive measures that can be used to increase the chances for successful open water survival including methods of tethering.

Use layers, use PFD, avoid entering water if possible, locate survival whistle and signal lights. Survivors should tether themselves together and stay with overturned vessels. H.E.L.P. Heat Escape Lessening Position

Explain the benefits for getting your body out of the water as much as possible in open water survival situations.

Getting out of the water will increase body temperature.Thermal conductivity of water is more than 20 times that of air

Explain risk-based decisions associated with swimming in open water survival situations.

Swimming will increase rate of heat loss and onset of hypothermia. Consider distance to shore, current physical condition, swimming competency, and water temperature.Will push out warm water trapped between clothing layers. Unnecessary movements send warm blood from inner core to outer layer of body resulting in heat loss.

Describe the method for:a. Climbing onto an overturned boat hull.b. Boarding a boat from the water.c. Boarding a life raft.

a. Look for easiest access point (stern), use design for hand holds, look for leverage points beneath surface, and assist other survivors. Stay away from stern, throw line over hull port to starboard, one person on each side, assist pulling each person on hull b. Consider swim platform/ladder, lowest point of freeboard, transom door, and Jacobs ladder. Strongest boards first to help weaker up c. Use buoyancy of PPE to spring up, legs together and dolphin kick, grab top tube and straps inside raft to pull in, and get help from people inside raft. Try to board directly from sinking vessel. If vessel is sinking rapidly, cut the line & board from the water.

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29 Hull

Planing Hull

A planing hull is designed to rise up and glide across the surface of the water once the boat reaches a certain speed.

29' Keel

29' - The 29FT RB-S II does not have any additional plating or reinforcement alongthe forefoot of the hull. The plate on either side of the keel below the bow isthe same 3/16 inch thick plate as the rest of the bottom plating.

Flat Plate Keel

29' Boat Characteristics (Length)

31Ft 8in

beam

8 FT 5 in

maximum fixed height above water, not making way

7 FT 10 in

maximum height above water ( antennas up )

9 FT 10 in

Draft (keel and lowest appendage)

2 FT 9 in

Maximum fixed height above ground when properly prepared for trailering

10 FT 6 in

Name and define the measurements used to define boat displacement.

Measurement: displacement is the weight of a boat and is measured in long tons (2,240 pounds)• Gross ton: entire cubic capacity of a boat expressed in tons of 100 cubic feet• Net ton: carrying capacity of a boat expressed in tons of 100 cubic feet. Calculated by measuring the cubic content of the cargo and passenger spaces.• Deadweight: is the difference between the light displacement and the maximum loaded displacement of a boat and is expressed in long tons or pounds.• Light displacement: weight of the boat excluding fuel, water, outfit, cargo, crew, and passengers.• Loaded displacement: includes weight of fuel, water, outfit, cargo, crew, and passengers

Two primary FACTORS that affect boat's stability

Gravity and buoyancy are the two primary factors acting upon a floating vessel that affect stability.

Define center of gravity and state how it changes as weight is added or subtracted upon the boat

The center of gravity is the point at which the weight of the boat acts vertically downwards. Thus, the boat acts as though all of its weight were concentrated at the center of gravity. Generally, the lower the center of gravity, the more stable the vessel.

The center of gravity of a boat is fixed for stability and does not shift unless weight is added, subtracted, or shifted. When weight is added (e.g., vessel takes on water), the center of gravity moves toward the added weight. When the weight is removed, the center of gravity moves in the opposite direction.

Define buoyancy

The buoyancy is the upward force of water displaced by the hull. The force of buoyancy keeps the boat afloat; however, it may be overcome if too much weight is added.

Define equilibrium and state how it is changed during rolling, heeling, and listing.

When a boat is at rest, the center of buoyancy acting upwards/vertically is below the center of gravity acting downwards.

• Rolling: This is a temporary, dynamic, side-to-side motion caused by waves or wind. As the boat rolls, the center of gravity shifts in the direction of the roll, and equilibrium is maintained as the forces of gravity and buoyancy offset one another to return the boat upright. [1, 2, 3, 4, 5]

• Heeling: This is a temporary leaning to one side, usually caused by external forces like wind in the sails or tight turns. The underwater shape of the hull changes, causing the center of buoyancy to shift toward the more deeply immersed side, temporarily offsetting the vertical alignment between the center of gravity and the center of buoyancy. [1, 2, 3, 4]

• Listing: This is a permanent or semi-permanent leaning to one side caused by uneven weight distribution within the boat. Equilibrium is reached only when the boat heels far enough to bring the offset center of gravity and the center of buoyancy back into vertical alignment. [1, 2, 3, 4, 5]

Two types of stability

Longitudinal - long way, bow to sternAthwartships/Transverse - side way, starboard to port.

Two types of FORCES that affect stability

Static - caused by placement of weight within the hull. Adding weight on one side of a boat's centerline or above its center of gravity usually reduces stability·Dynamic - caused by actions outside the hull such as winds and waves.

Boat design features that influence stability

General vessel design features that influence stability include:

(01) Size and shape of the hull,

(02) Draft of the boat (the distance from the surface of the water to the keel),

(03) Trim (the angle from horizontal at which a vessel rides),

(04) Displacement,

(05) Freeboard,

(06) Superstructure size, shape, and weight,

(07) Non-watertight openings. Many of these features are discussed in CHAPTER 3 Boat Characteristics

Effects of freezing spray

Freezing spray causes icing which adds weight and affects center of gravityIcing can increase the displacement of a boat by adding weight above thecenter of gravity causing the center of gravity to rise. This can cause a vesselto heel over and greatly reduce stability. Sea swells, sharp turns, or quick changes in speed can capsize a vessel that has accumulated ice on its topside surfaces

Describe the effect on boat stability when transiting from ice to open water and vice-versa

Increases displacement. To combat, change course or physically remove ice.