Reading bottom underway

[MikePA]

Any tips on how to dial in the sonar transducer to read bottom while underway.. doesn't have to be too fast.. hoping for 7-10km/hr (seems ok at 3-5km/hr) while looking for a place to drop my traps. Everytime I do this now I lose bottom. I've got a crappy Lowrance hook 7 with the transducer that comes with it.. are some transducers just crappy at achieving this? I've tried a few of the different tips I've be read on different sites (2mm of inside edge overhangs of hull bottom) and can't seem to get it right.

 

[Flashman]

Transducers can be very sensitive to installation location. This might be a good place to start:

https://www.airmar.com/uploads/SpecApps/transducer-installation-tips.pdf

 

[Sharphooks]

If you’re losing bottom at 10 km/hr you have crappy transducer location on your boat and the picture/targets are getting obscured by air bubbles

I noticed the upper level Lowarance Hook “Reveal 7” has chirp capabilities. If that’s what you have do yourself a favor and look into the way your transducer is mounted....it’s not complex—-generally you’ll get a better picture with a transducer mounted on the starboard side of the transom due to the direction the outboard props are spinning. The leading edge of the transducer bottom should be just below the bottom of the boat, tilted at a slight angle (13-17 degrees) from straight-down perpendicular (but not too much)

I’m guessing you’ll be better off with this installation info below. The above Airmar sheet is for way more complex installations then you probably have

https://www.airmar.com/uploads/installguide/17-122.pdf

 

[salmonkiller01]

I had a hook 7, worked great until
It did not As Sharphooks said your transducer location or mounting is the issue. If that is not the issue talk to harbour on chandler on best settings

 

[mbowers]

Definitely get the transducer in the right spot but two other things can help:

Set a manual depth range instead of automatic so while you might not get a number on the screen you can probably still see the return from the bottom.

Put your trim tabs down: puts more hull in the water so bubbles don't reach the transducer as easily.

 

[zurk]

mine loses lock at around 30km/h - too many bubbles. its fixed on the transom transducer plate around 0.5 inches behind the transom in line with the bottom of the hull, 2.5ft from starboard edge. lowrance HST WSU 83/200 skimmer unit.

 

[salmonkiller01]

mine loses lock at around 30km/h - too many bubbles. its fixed on the transom transducer plate around 0.5 inches behind the transom in line with the bottom of the hull, 2.5ft from starboard edge. lowrance HST WSU 83/200 skimmer unit.

That’s pretty good mine is the same in 200’ plus. Thru hull airmar

 

[MikePA]

Thanks everyone. I'll try other placements.. seems like it's in the normal position compared to other people with the same boat.. I'm sure there's lots of variables that can make a difference.. engine mounting height, prop etc

 

[Corey_lax]

Glue a piece of thick starboard or something to your transom so you can play around with placement of the transducer without drilling holes in the boat. I glued a piece of 1” lexan on and maybe moved my transducer 3/4” and it made a world of difference. That’s how picky these things can be. Now I can see my cannonballs on the screen and don’t lose bottom until I’m well under speed in deep water.

 

[ChilliSpoons]

Have you played with your settings on your Hook 7? Much easier to try that before moving the transducer location.

 

[MikePA]

Have you played with your settings on your Hook 7? Much easier to try that before moving the transducer location.

I've adjusted them around a bit. Any suggestions of typical settings that are not effective?

 

[MikePA]

Glue a piece of thick starboard or something to your transom so you can play around with placement of the transducer without drilling holes in the boat. I glued a piece of 1” lexan on and maybe moved my transducer 3/4” and it made a world of difference. That’s how picky these things can be. Now I can see my cannonballs on the screen and don’t lose bottom until I’m well under speed in deep water.

Thanks.. this was my next thought. What did you use for an adhesive?

 

[ChilliSpoons]

I've adjusted them around a bit. Any suggestions of typical settings that are not effective?

You should be able to find some YouTube video specific to your Hook 7.

 

[Corey_lax]

Thanks.. this was my next thought. What did you use for an adhesive?

Sikaflex. I ripped some ribs into the lexan to give the sealant more material to adhere to.

 

[MikePA]

You should be able to find some YouTube video specific to your Hook 7.

There's surprisingly very little, I've looked in the past. Lots for the higher end units.

 

[tbeatm]

Mike, I also have a 542. Used the same method of mounting the transducer as Corey_lax basically, with a piece of starboard sikaflex'd onto the transom for the bracket/transducer.

I have the Lowrance HDI skimmer L/H with my Elite FS setup and when its properly placed, it reads bottom up to 25/30km/h. Took a couple trips to dial it in for bottom personally. Biggest difference maker to dial it in was getting it level and clicking it down once so the tail end of the transducer was slightly below the front - so the face of it is at a very minimal angle facing forward if that makes sense.

 

[SpringVelocity]

This is why I went to thru hull. Never have this problem anymore.

 

[MikePA]

Mike, I also have a 542. Used the same method of mounting the transducer as Corey_lax basically, with a piece of starboard sikaflex'd onto the transom for the bracket/transducer.

I have the Lowrance HDI skimmer L/H with my Elite FS setup and when its properly placed, it reads bottom up to 25/30km/h. Took a couple trips to dial it in for bottom personally. Biggest difference maker to dial it in was getting it level and clicking it down once so the tail end of the transducer was slightly below the front - so the face of it is at a very minimal angle facing forward if that makes sense.

Would you mind sending a pic when you have a sec

 

[mgreen5228]

Different transducer but I fought this for a while. I raised it lowered it. Changed the angle and did not solve it. Finally realized that one of the bottom strakes was causing bubbles. I had a new plate welded on so I could move the transducer. I decided I wanted to get near the center to get the cleanest water possible. First try on the new location and I can see clear bottom to 30 mph. Good thing I went out to take a pic, I see the cable needs to be attached better. For me,the tab position does not affect the ability to read bottom.

 

[wolf]

I did somehting a few years back with a back of boat transducer I attached it to a piece of 3/4 starboard about 30 inchs by about 3 inchs wide as I HATE drilling holes in my boat put it on the "stick" then 2 screws above the water line with sika on screws. and the cable holders all the way done the stick and then you can rellay fiddle with transducer to get it perfect.. I got the starboard at a place that sold it, if I remember it was like 10 buck out of the scrap bin,

Hope that helps
Good luck wolf