Topic: XPTH-9-HDSi-180-T installation

[angler1]

Hello, planning to mount the through hull  XPTH-9-HDSi-180-T transducer and I want to clarify a couple things while reading the instructions.

I am mounting this in a step area, center of the boat, directly in front of the outboard engine.  The step is about 7-1/2 deep and about 5-6" above the bottom of the hull.  The step is perfectly parallel to the ground, so no deadrise leveling block messing around should be necessary.

Two questions - first the instructions say to make sure nothing is in front, behind, or side that is closer than 12".  In my mounting location, the back of the step will be within an inch (in front of the tranducer) and the lower engine unit will be about 12" trimmed in.  (see picture).  Nothing will be to the sides.  Is this location a problem?  I thought down and side was the only problem??

Second questions, when the deadrise is less than 2 degrees, the instructions seem to say to use the leveling block, uncut, and mount to outside of the hull.  Is using the leveling block necessary??  If my surface is parallel to the ground/water, do I need the block?

Thanks

[Humminbird_Greg]

angler1,
The XPTH-9-DHSi-180-T transducer is about 6 inches long.  The distance from the mounting stem to the front of the transducer is almost 2.5 inches.  So you would need at least 2.5 inches in front of the (1 inch) mounting hole to fit the transducer in.

If it will fit there than your next concern should be if it will disrupt the water flow to the propeller.  At higher boat speeds the transducer may cause an air pocket to form that can cause your propeller to spin out.

Depending on thickness of the boat’s hull, the leveling block may be need inside the hull even if it not needed outside the hull.  This is to help seal the transducer to the hull as the mounting stem is not threaded all the way down to its base.  The leveling block is also used to get the face of the transducer deeper into the water so that there are no air bubbles flowing across it.

[Rotus623]

Hi angler! Just some of my .02 here. It takes a lot of finnicking to get the SI ducer right where you will ultimately want it to be. If you drill a hole in the center of your hull and find that the transducer cavitates or does not work exactly as intended are you going to remove it and drill another hole elsewhere?!? The transom mount transducers seem to work very well, and since you cant get good SI scans over 10mph, getting high speed on plane readings is a null point anyway. Two reasons why Id consider a thru hull SI transducer: 1.) I did not have power trim. 2.) I had to many blockages to the sides of the transom (step ladder, aerator screen, etc.)   Just curious, what made you decide to go with the thru hull ducer?

[angler1]

Humminbird_Greg, thanks for the info.  The step is about 7-1/2 deep so it will fit here and still be fully covered under the step.  Down and sides will be wide open, but in front of it about an 1" will be the back of the step.  Does this matter?  The instructions mentioned having nothing in front within 12".

You answered an earlier post I had and did mention the water flow/cavatation possibility.  I did post on the manufacturers site, and did get an ower who has a side imaging tranducer in the same location without a problem.  But..you and Rotus623 are scaring me.  Since this is in a step area, at higher speeds, on full plane, this step should be out of the water mostly I would think.  I know you can tell me one way or another, but off the record, what's your logical guess at this being a problem?

For the block question then, it is not necessary outside of the hull and I can just flush mount the tranducer (assuming I don't need to push it down in the water further...where cavatation bubbles might become more of an issue).

Rotus623 - the main reason is that I keep the boat in a river marina slip much of the season.  My slip collects some debris behind it (I have to back in bow up stream).  With the boat bouncing up and down, the debris constantly lifted my transom transducer up and down, and I would be hanging over the back of the boat everytrip, re-adjusting that after pulling out of the slip.  This step area is nicely under water and below floating debris.  But you are scaring the crap out me if I have to mess around with it.  Mission accomplished.  Now make me feel better and tell me this makes some sense now. 

Thanks gentlemen..appreciate any of your thoughts.

[Rotus623]

Not trying to scare ya brother.  I can understand why you are putting the 'ducer thru the hull in your case. Not sure if you have a bow mount trolling motor, but I know a few people that have a transducer splitter, keep the 2d transducer on the transom, and dip their trolling motor into the water at 10MPH or less to run side imaging. Cool thing about that is you dont have to worry about turbulence as much with the ducer up ahead of the hull. Just an option. Another option is a spring mount for the transom ducer. It spring loads the transducer so that it keeps it down in the water, but will bump up if you have an impact. Look around on here and you will find more info on it. If you do go thru hull, just don't drill on impulse!! Listen to Greg and see if you can find others on here that have a similar setup as yours. Also post us a few pictures of the bottom of your hull so we can get an idea. Measure twice, cut once.

[angler1]

Thanks Rotus624.  Here on some pics.  I could mount off center I guess.  Cleaner in the middle.  What do you guys think.

[Humminbird_Greg]

angler1,
The 12 inch clearance is so that you will get good water flow around the transducer.  With the transducer mounted on a step in this location, it won’t get good water depth readings at faster speeds.  In fact I don’t know when the water depth readings will drop out.  Installing an XP-9-20 inside-the-hull DualBeam transducer and an AS-Si-DB-Y transducer splitter cable would take care of this.  If someone else with the same boat has mounted a transducer there and it not caused problems, I would feel more comfortable in doing so on my own boat.  I know that several have mounted an Si transducer (both Thru-Hull and transom mount type with an adapter bracket) to that are on Ranger boats without a problem.

Yes, you can mount the Thru-Hull transducer without the leveling block.

Some options I thought that you may want to explore is a bracket that would allow you to install a transom mount transducer up under the step.  This would get by drilling a big hole up through your hull.  Another possibility is a kick-up/flip-up bracket that automatically resets like Rotus mentioned.  I’ve heard that these are available from other companies.

[angler1]

Thank you Greg.  I actually do have the XP-9-20 and the AS-SIDB-Y cable, and my plan was to do exactly this.   ...Put the side imaging nicely up in this step, and glue the XP-9-20 in the hull.  I probably would try just the XPTH mount first and see how it performed.

I started this plan thinking it would solve my debris problem, be nice, center, and well protected in the step, be a super clean looking install with nothing on the outside transom.  I don't think I'm afraid of drilling the hole and using 4200 or a premium under water sealant.  But sounds like many are afraid, so this is concerning.

So it sounds like from you, that the biggest concern would be if it caused turbulance into the lower unit at higher speeds.  And with the splitter and XP-9-20, actual sonar performance could work fine with this entire plan and location.  Thank you.

[Humminbird_Greg]

Yes, but I still don’t like putting big holes in a boat hull! 
Let us know how it all turns out (including screen snapshots).