[CA] [CA11] RV-100 Transducer Placement

[DFMott]

I am looking for help with the installation of my RV-100 transducer. My boat has a deep V hull designed with a stepped transom. Everything I have read indicates it needs to go below the stepped transom near the center of the hull. This is well below the waterline. The obstacles are a garboard drain, scupper and compartmental drains and a B163 transducer on the starboard side and the same less the B163 on the port side.

Question 1 - Can you look at the attached photo and indicate where the best position for the RVB-100 would be? I would prefer the starboard side only because it is a shorter distance to the MFD but i am pretty sure the cable is long enough.

Question 2 - Hull Alignment. Since the hull is slanted and the transducer is flat I see there being three possible choices with regard to hull alignment. Can you look at the attached PDF and indicate which one is best?

[Chuck - Raymarine - Moderator]

Welcome back to the Raymarine Forum DFMott,

Q1 - Can you look at the attached photo and indicate where the best position for the RVB-100 would be? I would prefer the starboard side only because it is a shorter distance to the MFD but i am pretty sure the cable is long enough.
A1 - Unfortunately, all hulls are not suited to transom mounted transducers (note that a thru-hull transducer has been installed forward of the first step). This is because of the presences of a step forward of the sponsons and low vertical height on the step (insufficient to properly mount a transom mounted transducer). Accordingly, I would not consider this hull to be well suited for a transom mounted transducer should one be expecting to have the transducer support operation at speeds greater than trolling speeds. Instead, I would recommend that a through hull pair be considered for this application, particularly if seeking to have the transducer support operation at speeds faster than trolling speeds.

Q2 - Hull Alignment. Since the hull is slanted and the transducer is flat I see there being three possible choices with regard to hull alignment. Can you look at the attached PDF and indicate which one is best?
A2. The image which you have labeled "A" is correct for those seeking to have the transducer operate while the vessel is on plane.

[DFMott]

Obviously not the answer I wanted to hear but thank you.

You said "the low vertical height on the step (insufficient to properly mount a transom mounted transducer)" I believe I have 4"+ there. Wouldn't that be enough space to mount the transducer in position A on my diagram? And if so would that work if it were positioned close to the keel?

Installing a pair of thru the hull transducers presents issues as well because the fuel tank sits just behind where the B163 is mounted and i am not sure there is enough room for the RV3XX...

Q1 If there is room how close can it be to the B163 and the rear of the hull (Where the step begins)?

Q2 Are there any benefits to the stainless or bronx over the plastic for a boat that sits in salt water 24/7?


Thank you for your help.

[Chuck - Raymarine - Moderator]

DFMott,

What is the thru-hull transducer shown presently interfaced to? If compatible with the Raymarine MFD, why not consider using it for bottom tracking while operating a higher speeds than can be supported by the RV transducer. The RV transducer could then simply be used at trolling speeds ... where it primary function (support of fishing) will be supported?


Q1. I believe I have 4"+ there. Wouldn't that be enough space to mount the transducer in position A on my diagram?
A1. According to the RV-100's installation template, it will require a bit over 4" of vertical surface to properly install the transducer such that it satisfies your diagram "A". The transducer should not be installed directly forward of the swing of the propeller, behind any thru-hulls, or behind any chine or other hull features which may produce an aerated flow of water across the face of the transducer. It also would not be recommended that its cable be installed in a manner which would cause it to be run along the bottom.

Q2. If there is room how close can it be to the B163 and the rear of the hull (Where the step begins)?
A2. Raymarine has issued no specifications regarding how far forward of the transom or how close to other transducers that the RV thru-hull transducers may be installed. The requirements simply specify to not locate them directly forward of props or other thru-hulls and to not locate them directly behind other thru-hulls or hull features which may cause an aerated flow of water across the transducer. Installations on challenging hulls are where the experience of a Certified Raymarine Installer may be worth the money spent.

Q3. Are there any benefits to the stainless or bronx over the plastic for a boat that sits in salt water 24/7?
A3. Negative. While all three are compatible with fiberglass, plastic or bronze thru-hulls will typically be used. Some hulls, such as those constructed from wood or aluminum, will require bronze or stainless steel thru-hulls.

[DFMott]

I am trying to make the best of a sub-optimal situation here and appreciate your help.

First let me say that I troll at 8 knots with 4 lines in the water 80% of the time and when I am not trolling I am not looking for fish.

That being said I went to the boat and measured and there is simply not enough room to install a pair of RV-3XX thru the hull sensors so I need to find a way to make the RV-100 work.

Option A - I can install the RV100 on the step close to the Garboard drain (see attached diagram) on the left side at a location where there is nothing but smooth hull in front of it. I have attached a drawing. The wire would have to travel about 10" horizontally (either on an angle or attached to the hull) before running up the transom.

Option B - I can install the transducer in the exact center of the hull above the step.

Can you opine on which option is the better choice and why?

[Chuck - Raymarine - Moderator]

DFMott,

Q. Can you opine on which option is the better choice and why?
A. On hulls lacking steps and feature twin outboard or twin I/O propulsion, it would typically be recommended that the transducer be installed between the drives on the centerline.



However as indicated previously, a transom mounted transducer would not typically be recommended for this application. Mounting the transducer to the step may cause too much of it to be suspended beneath the hull, may prevent it from kicking up if it strikes something, and could pose issues with passing the cable through the transom & sealing the transom. Mounting the transducer to the location marked B (bottom centerline portion of transom of the step will cause the transducer to be aerated as the vessels speed increases toward planing speed and I suspect that it may well occur at or below 8 kt trolling speed indicated. As suggested within my earlier response, installations on challenging hulls such as yours are where the experience of a Certified Raymarine Installer may be worth the money spent. A list of Certified Installers in your area may be accessed by clicking here. Those Certified Raymarine Installers who are also Premier Dealers would have the most experience with Raymarine equipment installations.

[DFMott]

Unfortunately there are no certified Raymarine installers on the Island I live on so I am on my own. I am not sure what you mean by "too much of it to be suspended beneath the hull" and what issue that creates. If you could please explain.

[Chuck - Raymarine - Moderator]

DFMott,

Q. I am not sure what you mean by "too much of it to be suspended beneath the hull" and what issue that creates.
A. The installation guide for the RV-100 identifies the transducer's height with respect to the bottom of the hull. Should the transducer be installed lower than specified with respect to the bottom of the hull, then it will be subjected to more drag force, may aerate sooner, and may be more exposed with regard to strikes from floating debris. Additionally, should the installation location not permit a transom mounted transducer to kick up should it strike debris, then the transducer may be damaged or its bracket torn from the hull as a result of striking debris. If seeking the best performance in conjunction with this hull, it would be recommended that the currently installed transducer be relocated to permit a thru-hull RV transducer pair to be installed.

[DFMott]

Would a single RV-200 mounted on the port side on a fairing block work?

[Chuck - Raymarine - Moderator]

DFMott,

Thru-hull RV transducers are not designed for use with fairing blocks. These transducers are designed and tested to be surface mounted to the hull. Accordingly, results with a fairing block cannot be predicated.