[CA] [CA11] Locating RV-220 Transducer

[Bradfish]

I'm trying to decide where to locate my new RV-220 transducers on my 35' Albin Tournament Express. The raw water intakes for the engines are located exactly where the installation instructions indicate they should go. I either have to move the intakes or find a new place for the transducers. Moving the intakes creates as many headaches as it solves so I'm trying to find a secondary location for the transducers.

I have done some research on this forum with regards to some issues I'm having in locating the transducers but haven't found the answers. The main issues are:

1) This boat has a skeg that sticks down about 12" (see attached photos) and if I put the transducers too close to the skeg I'm worried about reduced performance. How close to the skeg can the transducers be without suffering reduced performance? How will the reduced performance (if any) manifest itself if they are located too close to the skeg?

2) I recall reading somewhere that the transducers should be kept within 3' laterally and close to the same position longitudinally of each other. If I locate the transducers outboard of the inboard stringers they will be right about 3' apart. What is the max separation of these transducers?

3) Are there any noise issues with locating the transducers under the engines (Cummins 6BTA)?

Thanks for your help!!

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Bradfish,

This hull definitely poses some challenges and you may want to consider enlisting a Certified Raymarine Installer who is familiar with RealVisionâ„¢ transducers and such hulls for the installation. Given our choice, the recommendation would be to install the transducers in the location presently occupied by the water pickups (as long as the transducers will not aerate the props) and to consider moving the water pick-ups inboard or outboard of the transducers. There is some overlap in coverage by the transducers, the amount of which will be dependent upon the hull's deadrise and the distance which the transducers will be separated. Where such overlap does not occur, an blind spot will occur, which will be widest at shallow depths and will decrease as the water depth increases.

Given the deadrise (13 degrees as indicated by one Internet source), it would be recommended that a RealVision™ (RV) 3D Thru-Hull Transducer, 12°, split-pair be installed. The maximum distance that the RV transducers may be separated is a little less than seven feet. As the hull features a skeg, it would be recommended the transducers be located away from the skeg to prevent exposure to aerated / turbulent water (see the recommendation above). The same may occur if the transducer is installed behind aft of a thru-hull such as a water intake. This condition may adversely affect fishfinder performance when the vessel is operating at planing speeds, and will typically manifest itself in loss of bottom. RV transducers feature an AHRS to permit the RV processing to compensate for vessel motion. As the AHRS is a magnetic north seeking device, performance of such compensation may be adversely affected by installation of the RV transducer in close proximity iron (ex. engine blocks, skegs (varies based upon construction), etc.) and other sources of magnetism. AHRS compensation may be disabled should the installation locations for the transducers place them too close to a source of strong magnetic fields.

Please additionally note that I generally recommend that either a 1kW CHIRP transducer(s) or a 50kHz/200kHz transducer be installed to support tracking bottom at planing speed and to support operation in depths greater than may be supported by RV transducers.

[Bradfish]

Chuck,

Thanks for the good advice . After much consternation and head scratching, I've finally decided where to place my transducers.

You mentioned that some research indicated the deadrise on my boat was 13 deg. Thirteen deg is the deadrise at the transom of the boat. I took some deadrise measurements forward, under and aft of the engines on both sided of the boat. The place with the cleanest water flow is forward of the engines. The deadrise in this section of the boat is just under 20 deg so I do need the RV-220 transducers. This placement also gives the most distance from the engines to reduce engine interference.

The lateral distance between the transducers is about 44", well within the 7' max. separation. This separation is also plenty far enough away from the skeg to avoid blind spots in shallower water.

The longitudinal position on the boat is about 16.5' forward of the transom. This is probably less than ideal but the transducers should remain in the water as the boat rises and falls on the seas.

Thanks again.

Brad

[Chuck - Raymarine - Moderator]

You're welcome and it sounds as though you're on the right track to proceed with the installation.

[Bradfish]

Chuck.

One last question. What antifouling paint does Raymarine recommend to use on these transducers?

Thanks.

Brad

[Chuck - Raymarine - Moderator]

Brad,

Q.What antifouling paint does Raymarine recommend to use on these transducers?
A. Please click here to view a FAQ addressing this subject. One such example is MDR's MDR720.