🚀 go-pugleaf

	Several Years Ago, I read an advertisement in SAIL
	or some other such magazine on a knotmeter which
	measured doppler phase difference through the
	hull of a boat in order to determine the
	speed over water.
	Basically, the instrument mesured time delay
	between two trancducers, for transducer 1 to
	transducer 2 and also for transducer 2 to
	transducer 1. The difference in delay will
	allow computation of the speed of the medium.
	The method is often used in industry for
	velocity measurements of corrosive fluids
	inside plastic piping, because of its
	nonintrusive quality.
	I would like some help from anyone who
		1) Can point me to some technical
		   litterature on the subject

		2) Can tell me who makes these
		   types of instruments

		3) Owned a system or knows the hearsay
		   of the performance of these 
		   systems.
	
	I greatly appreciate any help on this. Thanks in advance.

			Edwin Muth
			homxb!edwincp
			(201) 834-1447
			AT&T Consumer Products in Holmdel
			Keyport Yacht Club, Keyport, NJ