Coverage in shallow water

[Fotomaker]

I am interested in the Wi-Fish for use on a pontoon boat on a lake with a maxim depth of 15 feet and an average depth of 4-6 feet.
Will this product pick up enough area of the bottom to be useful?

Do you have a graphic that will depict the coverage angle at various depths?

Thanks!

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Fotomaker,

Your question regarding usefulness for the depths specified is a subjective (i.e. what may be necessary to some may be excessive or not meet the requirements for others). While Raymarine has not posted a graphic providing the requested coverage at various depths, the diameter of the transducer cone at any specific depth is easily calculated and address in the FAQs found here and here.

[Fotomaker]

Looking at your links, it appears that the cone size at 10 feet would be 11.5 feet in diameter. I read somewhere in my Wi-Fish research that it has a 60x1.4 degree cone shape that is a very narrow oval.

Please provide me with the WiFish cone dimensions at both 10 and 5 foot depths so that I may have the info I need to decide which product to buy.

Thanks very much!

[Chuck - Raymarine - Moderator]

Fotomaker,

Unlike the Dragonfly Pro displays which support both CHIRP (conical) sonar and Downvision, the Wi-Fish exclusively supports DownVision. As indicated within the previously referenced FAQ, the multiplier for determining the DownVision side to side axis (60 degrees) dimension at depth is 1.154 * Depth

.... side to side axis dimension at 5' depth = 1.154 * 5' = 5.77'
.... side to side axis dimension at 10' depth = 1.154 * 10' = 11.54'
.... side to side axis dimension at 30' depth = 1.154 * 30' = 34.62'
.... side to side axis dimension at 100' depth = 1.154 * 100' = 115.4'
.... side to side axis dimension at 500' depth = 1.154 * 500' = 577'


As indicated within the previously referenced FAQ, the multiplier for determining the DownVision fore to aft axis (1.4 degrees) dimension at depth is 0.01222. The thin, but relatively wide sonar imagery slices produced by the DownVision elements are combined to produce the detailed DownVision sonar image.:

.... fore to aft axis dimension at 5' depth = 0.01222 * 5' = 0.0611'
.... fore to aft axis dimension at 10' depth = 0.01222 * 10' = 0.1222'
.... fore to aft axis dimension at 30' depth = 0.01222 * 30' = 0.3665'
.... fore to aft axis dimension at 100' depth = 0.01222 * 100' = 1.222''
.... fore to aft axis dimension at 500' depth = 0.01222 * 500' = 6'

[Fotomaker]

Thank you... That was very helpful. In your opinion, will the addition of CHIRP (conical) sonar be useful in my shallow water location. I am actually more concerned with threats to the hull by underwater stumps and rock protrusions, and the ability to map these problem areas, than I am in looking for fish. If you could only have either DownVision or CHIRP (conical) sonar, which would you choose for my situation?

Thank you again!

[Chuck - Raymarine - Moderator]

Fotomaker,

Given that the DownVision sonar elements of transducers designed for use with Dragonfly, Wi-Fish, CP100, ax8 MFDs, and eSx8 MFDs only scan 1.4 degrees in the fore/aft axis, you may be better served by a Dragonfly display, as unlike Wi-Fish, it supports CHIRP (conical) sonar which scans in a 25 degree cone.