tug equipment identification

[Karl]

Hmmmm tube with mirrors inside allowing a view of something. Periscope was not too far wide of the mark.....

[papersurprise50]

It is a scope for reading the repeater .Now wouldn't that be tempting for a stupid captain to fix it so's you could look around .He could ,then , as the tug is getting squished and pushed down issue the order ," Come to periscope depth " OOH .

[rpeteru]

The reason for this is the magnetic compass is on the monkey island as stated previously. Other means of showing vessel heading on the bridge are usually of an electronic nature. Normally an electrical/electronic repeater unit fed from the gyro compass. When power fails these become non operational and old fashioned vessel headings (directions) are taken from the magnetic compass card whose image is projected through a tube usually via mirrors.