sonar fish

[Cal]

Hi, Jan & bill, An easy way to make a water-tight fish is to use pvc pipe repair sections that you can buy at most hardware stores. They are o-ring sealed and are good for 3 or 4 hundred p. s. i. [ A 100 p.s.i. is good for over 200 ft. of depth.] .47 lbs for each foot of depth. These sections come apart and you can buy them in many different dia. You use pvc pipe and end caps with them. In the end cap I drilled a hole & put in a tire valve [ fiber-glassed in] so that I can preasurize the fish. This also lets me know if I have any leaks when I put it in the water. [ this is in the end cap at the back of the fish.] To tell the depth of the fish I'm using a nemo hose, like you use with commerical diving gear. The hose is 1/8 inch dia. and in the boat the top end is connected to a small scuba tank and a guage calabrated for water depth in feet. After making any speed or direction changes you open the valve on scuba tank for a very short time to reset the air and water columm in the nemo hose.

[Bill]

Re: sonar fish

>Hi, Jan & bill, An easy way to make a water-tight fish is to use pvc pipe repair sections that you can buy at most hardware stores. They are o-ring sealed and are good for 3 or 4 hundred p. s. i. [ A 100 p.s.i. is good for over 200 ft. of depth.] .47 lbs for each foot of depth. These sections come apart and you can buy them in many different dia. You use pvc pipe and end caps with them. In the end cap I drilled a hole & put in a tire valve [ fiber-glassed in] so that I can preasurize the fish. This also lets me know if I have any leaks when I put it in the water. [ this is in the end cap at the back of the fish.] To tell the depth of the fish I'm using a nemo hose, like you use with commerical diving gear. The hose is 1/8 inch dia. and in the boat the top end is connected to a small scuba tank and a guage calabrated for water depth in feet. After making any speed or direction changes you open the valve on scuba tank for a very short time to reset the air and water columm in the nemo hose.


Cal, what about the stabilizing fins and dive plane?


Also the length of the cable should be a factor.I


don't think that the fish should be a stand alone


unit because the possibility of underwater collision


is not great. The transducing unit should not be made


complicated, as it's main function is only to give


a picture of the area.

[Jan]

Re: sonar fish

>>Hi, Jan & bill, An easy way to make a water-tight fish is to use pvc pipe repair sections that you can buy at most hardware stores. They are o-ring sealed and are good for 3 or 4 hundred p. s. i. [ A 100 p.s.i. is good for over 200 ft. of depth.] .47 lbs for each foot of depth. These sections come apart and you can buy them in many different dia. You use pvc pipe and end caps with them. In the end cap I drilled a hole & put in a tire valve [ fiber-glassed in] so that I can preasurize the fish. This also lets me know if I have any leaks when I put it in the water. [ this is in the end cap at the back of the fish.] To tell the depth of the fish I'm using a nemo hose, like you use with commerical diving gear. The hose is 1/8 inch dia. and in the boat the top end is connected to a small scuba tank and a guage calabrated for water depth in feet. After making any speed or direction changes you open the valve on scuba tank for a very short time to reset the air and water columm in the nemo hose.


>Cal, what about the stabilizing fins and dive plane?


>Also the length of the cable should be a factor.I


>don't think that the fish should be a stand alone


>unit because the possibility of underwater collision


>is not great. The transducing unit should not be made


>complicated, as it's main function is only to give


>a picture of the area.


Bill,


The sole reason why I would like to make the fish standalone is to be able to use a camera to investigate targets found by the sonar.


More often than not the currents will prevent a diver to go down and have a look. (outside slack(?) tide)


When running with camera one has to come near the target, increasing the change of collision.


I also like things to be easy, so I prefer to set a set of thumbwheel switches for depth and forget about the fish (knowing it will run at that depth)


But our main goal is to design a sidescan sonar, so I think that people can decide themselfs what kind of fish they want to use.


Seeing the amount of responses on the fish post I think most people think the same way as you so I will


not make a seperate project out of the fish.


Lets start on the sidescan sonar.


Regards,


Jan.