180	NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
 3.	What is a navigation light sentinel?
 4.	Describe the marks on the hand lead line and on the deep sea line.
 5.	What soundings would you call out for:—(a) leather with a hole
in it; (6) first red rag 6 feet below the surface; (<?) blue rag 6 feet above'
the surface; (d) second white rag 3 feet above the surface; (e) second
red rag 18 inches below the surface?
 6.	Describe how a cast of the deep sea lead would be taken steaming
before the wind'and sea.
 7.	Describe taking a cast with a patent depth recorder.    How can
you tell when the lead has touched bottom?
 8.	What is the principle of the atmospheric sounding tube.
 9.	Write out the best- description you can of the Echo Sounding
Machine.

 10.	What is the principle followed in measuring ofi the length of the
knot on the hand log line?
 11.	Describe a patent towing log.
 12.	Describe any electrical type of speed recorder you may know
about.
 13.	Supposing all speed recorders were lost how could you arrive at
the ship's speed?	9
 14.	Write out equations connecting the ship's speed  with coal
consumption.
 15.	Describe a sluice valve, bow it is operated and the manner
in which they are fitted.
 16.	What are the requirements of a steering gear?
 17.	Describe a type of steam steering gear and how the rudder is
operated by the helmsman.
 18.	What advantages  are claimed for telemotor  steering gear?
Describe how it works.
 19.	Describe the emergency steering gear in any ship you have
served in.
 20.	Describe the mechanism of a steam winch and how it works.
What precautions should be taken before starting and stopping a
winch, particularly so in cold weather.     Steam is escaping badly from
the cylinders of a winch, describe how you would repack the glands
and make it steamtight.
 21.	Name the essential parts of a reciprocating marine steam engine.
 22.	What are the fundamental differences between a Scotch boiler
and a water-tube boiler?   State the advantages and disadvantages of
each.