Ch. 15

Question 1

What is the difference between handling a dead ship and assisting a power vessel?

Answer 1

With a dead ship the tug is the prime mover, with a powered vessel the tug is assisting

Question 2

Is one tug ever used to handle a small ship by itself?

Answer 2

Yes, just as tugs frequently handle fairly large barges unassisted

Question 3

If only one tug is used and a hard turn is made, where should the tug be?

Answer 3

The tug should be hipped up on the inboard side of the turn, since even if the tug backs the ship will continue to swing in the direction of the turn. If the tug (especially a single screw tug) is on the outboard side of the turn, it may not be able to back since this will kill the swing

Question 4

How may a tug on the outboard side of a turn reach a point of no return?

Answer 4

If the ship’s turn rate is too slow and there is neither sufficient room ahead for the ship to advance or to the outboard side for the ship’s stern to rotate around its pivot point.

Question 5

Does a ship propelled by a tug on the hip have a tendency to skid sideways?

Answer 5

Yes, this is caused by the offset location of the steering and propelling forces.

Question 6

When a larger ship is shifted are more tugs required?

Answer 6

Yes, the number of tugs required (unless stipulated by port regulations) will depend upon the size of the ship and the horsepower of the tugs.

Question 7

Are vessels ever handled stern first?

Answer 7

Yes, but extra care should be taken when docking to avoid damaging the rudder and propeller.

Question 8

Describe several hookups for handling dead ships.

Answer 8

With two tugs a powerful tug aft for propelling and a smaller tug forward for steering placed on either bow. With 3 tugs the powerful tug aft on the hip and 2 tugs forward on each side for steering. Two tugs aft with one tug forward for steering or four tug two forward and two aft on either side.

Question 9

Why is the use of a tug on a towline forward and a tug hipped up aft an effective way to use tugs?

Answer 9

Because two moderately powered tugs can propel a sizeable vessel since both tugs are moving the ship. The forward tug can steer the vessel, and the after tug can back to check its way. This is an efficient use of power especially for longer shifts.

Question 10

How are tugs aft on beamy vessels used most effectively for steering?

Answer 10

By using the tugs as if they were a component of a twin screw ship and by using their engines in opposition for steering effect.