Drive a Boat Flashcards

1
Q

Interaction
The three situations of interaction the bridge team should be aware of are:

A

When a vessel moves through a seaway, it displaces the water in which it moves.

This results in pressure differences and causes interactional movement between vessels and their environment

Head on interaction
Overtaking interaction
Interaction in narrow channels

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2
Q

Head on interaction

A
  1. Vessels pass, bows deflected
  2. Attraction when passing alongside
  3. HP from propwash may shear sterns away from each other
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3
Q

Overtaking interaction

A
  1. Overtaking vessels bow shears overtaken vessels stern away, shearing their bow into the path of the overtaking vessel
  2. Attraction when vessels passing along side
  3. When bows aligned, bows will be deflected
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4
Q

Interaction in Narrow channels

A

Vessels should pass at as slow a speed as possible to minimise interaction with each other, banks, and shallow water

Also allows for extra thrust if needed to counteract interaction forces

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5
Q

Bank effect (Bow cushion effect)

A

Bow wave pressure shears bow away from bank
LP at the stern sucks stern towards the bank

Counteract by steering towards the bank, counteracting the shearing force of the bow

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6
Q

When berthing/mooring, what do we do in relation to the tide?

A

STEM the current

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7
Q

When forced to berth with the tide from astern with a single screw vessel, what do we do?

Same goes for leaving the dock with heavy tide/wind on the beam on a single screw vessel.

A

Call for TUGS

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8
Q

How to SNUB around

A

With current behind, drop leeward anchor

Allow tide to push vessel around and the wind to continue the swing of the vessel

Pick up anchor and drive out on the reciprocal

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9
Q

Short Round

A

Port side of channel

Hard to STBD

Midhsips, full astern

When way comes on astern, stop, full ahead, wheel to stbd

Wheel to midships when on reciprocal course

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10
Q

Open Moor

A

Stem the tide

Drop windward anchor, 2x amount required

Move transversely until anchor tight

Drop second anchor

Settle the difference by bringing in the 1st anchor until scope of chain required is met

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11
Q

Running Moor

Required when tidal waters risk lifting the vessels anchor

A

Drop 1st anchor, windward side, 2x chain required

Drive up into the tide, drop second anchor

Drive back and settle in the middle, bar tight on both

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12
Q

Standing Moor

A

Same as running moor, but start with high side of the tide first, and let the tide drift the vessel back

Then settle in between

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13
Q

What is Squat?
When is it most critical?

A

Hydrodynamic interaction between the bottom and the vessel
depth <1.5m of the draught of the vessel

Draws the vessel to the bottom, resulting in difficulty steering/sheering

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14
Q

Factors effecting squat:

A

Ships speed

Type of bow

Position of the Longitudinal Centre of Buoyancy
If aft, Squat by the stern expected.
If Fwd, Squat by the head expected

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