MANUAL OF TIDE OBSERVATIONS 



27 



Figure 15. — Intake coupling for float well. 



opposite sides of the pipe and facing in different directions. The 

 center of the upper pair should be about 1 foot below the top of this 

 section of pipe and the others arranged with centers approximating 

 3 and 5 feet below the top of the section. 



68. Wooden float well. — A wooden float well for use at a primary 

 tide station should usually be constructed of 2-inch by 14-inch planks 

 so assembled to form a box 12 inches square on the inside and long 

 enough to reach from the 



floor of the wharf to sev- 

 eral feet below the lowest 

 tides. A sloping bottom 

 with intake in one of the 

 lower corners should be 

 provided, the correspond- 

 ing corner at the top being , 

 marked for identification, 

 preferably by beveling off 

 the corner. When the 

 depth of water is not too 

 great, two opposite sides of 

 the box may be extended 

 below the intake to rest as 

 a support upon the sea bot- 

 tom. The outside of the 

 float well should be covered 

 with 16-ounce sheet copper from the bottom to a height above mean 

 high water as a protection against teredos and other marine animals, 

 copper nails being used in construction of the well as a precaution 

 against electrolytic action between nails and copper sheathing. 



69. Intake. — The intake to the float well should be of sufficient size 

 to permit the free access of the tide while damping down the effect 

 of heavy seas. The opening must, however, be large enough so that 

 rough water on the outside will always leave an unmistakable trace 



upon the tide record. In 

 protected localities an in- 

 take 1% inches in diameter 

 is recommended for a 12- 

 inch float well, but for 

 places exposed to heavy seas 

 an intake from % to 1 inch 

 is sufficient. A single large intake is to he preferred to several small 

 ones, as the former is less likely to become clogged and is more easily 

 cleaned when clogged. An intake should be in the bottom of the float 

 well rather than in the side to facilitate cleaning. For an iron float 

 well a special conical intake coupling is provided, and when installed 

 this is placed with the apex downward. For a wooden float well 

 a square hole may be sawed in one corner of the bottom before as- 

 sembling the parts. At the time of the installation of a primary 

 tide station facilities should be provided for the periodic cleaning 

 of the intake by the tide observer. (See pars. 132-135.) • 



70. Installation of float well. — Special care must be taken to secure 

 the float well in a vertical position in order that the float may rise 

 and fall freely without scraping the sides of the well. Where suffi- 

 cient depth is available, the well should be installed with the intake 



FiGDRB 16. — Cleaning tool for float well. 



