Sonar tips

[Big Green Machine]

I have a new dual frequency sonar and it works great everywhere except at certain times in the Alberni Inlet, where it loses bottom mostly early in the day. I have heard that the inlet water is "peaty" frequently. Could this, along with a tide change and unfavorable wind conditions contribute to losing a bottom reading?

 

[doger5]

Check out Airmar website, I bought a airmar b164 1000W trandsducer 1000W You get what you pay for.

 

[darinb]

yes this has happens to me. I solved this problem by pushing the transducer back to it original position. they get hit by junk when you are cruising once in a while and flip up to a diff angle. hope this helps.

 

[nedarb2]

quote:Originally posted by reelfast

my hull is a single thickness of aluminum. i had an inhull epoxied transducer in my previous ride, also aluminum. i don't know how well this would work in a fiberglass hulled boat.

you cant thru-hull fibeglass boats as the wood cores/any core has air pockets in it, which cant be shot thought with the sounder

 

[Melroy]

Hi,
I'm running a Lowrance HDS-5, With my old Eagle unit if you were trolling along and the depth changed you would hear a beep as the screen changed to match the new depth. All I can find on the new unit is the low water 6 foot alarm.
Thanks>>>Melroy

 

[chris73]

Tenmile: I think you just ran into a bunch of crap when you lost signal. Maybe you transducer needs cleaning too. Also, the 50khz is not ideal for showning details. You should be running the frequencies around 200 khz if you want to see bait/fish. The lower frequencies will give you generally greater depth range but less detail (similar to radio waves AM - FM)

nedarb2: Of course you can have through-hull transducers in fibreglass boats. The bottom of a fg boat has no wood in it but only resin. If the resin/glass is air pocket free it will give you superb performance. I would say better than through aluminum as the wave break/reflection at the material transition zone (alu-water or fg-water) should be greater as more the materials differ - and resin has more similar properties to water than metal to water. Plus if you epoxy a tranducer to metal you would actually deal with 3 different materials and therefore have 2 material transition zones with wave break/reflection - epoxy-alu and alu-water - which will cause your signal to lose strength.

 

[TenMile]

After further investigation, I found that my Lowrance skimmer was beginning to malfunction so I replaced it with an Airmar P79 that shoots through the fiberglass hull.

As above, the P79 design does actually create a "water-box". I used silicon to affix the cylinder to the hull and when it dried I filled it with RV antifreeze (you can use water or mineral oil too).

For me, the shoot-thru-hull design is much better. The transom mount would never hold bottom beyond trolling speed where the P79 will hold bottom and mark fish up to about 28kts and 400ft (or over 1000 ft while at trolling speed).

Super easy to install -- cleaned the area in the bilge with alcohol wipes, aligned the sensor and cylinder, used 3M clear silicon (the semi-permanent stuff), waited a few days for it to dry and added the anti-freeze, intstalled the transducer and away she went.

TenMile
<'((((><

 

[Degree of Freedom]

quote:Originally posted by nedarb2

quote:Originally posted by reelfast

my hull is a single thickness of aluminum. i had an inhull epoxied transducer in my previous ride, also aluminum. i don't know how well this would work in a fiberglass hulled boat.

you cant thru-hull fibeglass boats as the wood cores/any core has air pockets in it, which cant be shot thought with the sounder

through hulls work great on fibreglass boats. true if there was a core it would not work, but the bottom of most hulls are solid glass.
most important thing is making sure there are no air bubbles caught in the epoxy when you install it (use a slower setting epoxy).

 

[reelfast]

i have a dual frequency transducer. i have the sonar end of life configured to auto switch which is a depth dependent feature. my sonar works without fail at speeds of about 25mph, any depth. if i ramp up the speed to get out there in a hurry, the unit looses the bottom after about 150'.

all this means is the transducer i am using is not a high speed unit. if i ever get around to it i will epoxy a puck on the inside, aluminum hull really don't think this is a good application in a glass boat, as my past experience with this was that it functioned at any speed. or you could invest in a high performance transducer on the outside of your hull.

of course you may also have the transducer aligned incorrectly, too high or too low, to the transom. the leading edge of mine is about 3/16" below the keel. yup, i have fiddled with this and thats about the best performace i can get.

as already mentioned, you are 'seeing' the salad float under your hull when the depth goes from way down to 3', happens all this time as you are crossing tide scum lines.

 

[mbowers]

Using manual mode helps to keep the bottom visible at higher speeds because there is more noise and the auto can get confused trying to make sense of it all. Burying the trim tabs can make for cleaner water at the transducer which improves performance too.

 

[PW_Homer]

Links for Sonar settings etc

http://www.hightechfishing.com/education.html

http://www.hookedoncatfish.com/LowranceTips.html

I run my sonars always in manual mode as this gets the best results.

50KHZ is used best for deep water and for tracking/seeing your downrigger ball/balls. The detail at 50KHZ is very poor as this is meant just to see deep. 200KHZ provides the best details and should give you good detail down to at least 300 feet

I run a Airmar B260 (600 Watt 50/200) thru hull and when running holds bottom up to 40MPH + and only looses bottom after going beyond 500' plus

I also run an Airmar TM270W transom mount (1000 watt 50/200 both at 25 degrees). Far better image and resolution than the B260, sees the downrigger balls in 200KHZ but as with transoms mounts does not work as well at high speed holding bottom. Went the transom mount route only because of the high cost of the transducer and if I sold the boat I did not want to leave it on as a thru hull is there forever.


Be aware that in certain areas due to currents etc this can play havock on the sonar and can give false readings or not read bottom at all


/fishon