Finally got a clear picture at speed - FCV620

[marto78]

I have owned this unit for 3 years now and because of the shape of my hull it has been driving me crazy as I have not been able to get a clear picture at speeds over 20km/hr even on a calm day. After drilling countless holes and trying different store bought brackets all over the back of the boat I decided to design a bracket and take it down to the local engineer to weld up for me.

He did go a bit over board in the strength side of things. But after the results of the weekend where I was able to sit on 30km/hr in a 10-15kt northerly and spot a school of fish hanging off the back of a bombie in 65m of water I am very happy with the way it turned out.

I was even able to sit on 45km/hr on the way home and still get a perfect picture.

pic 1 is of the bracket up and out of the way.
DSC01145.jpg
pic 2 is dropped down in the clean water when cruising along
DSC01148.jpg

[Seahorse]

Mate what a good lookin bracket.
Glad it all works now

[nautimax]

Looks good! What is the make and model of your tranny?

[marto78]

Looks good! What is the make and model of your tranny?

Airmar P66

[Malcolm W]

Looks like you had to go deeper than most to get to clean water.

I've had a couple of p66s, one on a pressed bottom boat like yours and it took a lot of adjusting as well.

Bought my latest sliding bracket from BCF, not as good as yours though. Using it to slide up and down for beach launching.

[whiteman]

I couldn't get mine working with a Quintrex. Sold it and went to Garmin which is an inferior sounder but it does hold the bottom. Yours looks very deep (got a side on photo?). What's the rooster tail like? When I had mine in the deepest setting I snapped the plastic lock twice. I would go back to Furuno in a heartbeat if I could get a clear picture on the plane in a bit of chop. I used to lose depth over 10 knots and picture a lot earlier.

[marto78]

I found the deeper I run it the less rooster tail there was and I had a triangular piece welded onto the front of the bracket to make it a bit more slim line. It is also angled forward slightly for a bit less drag again.
I did have a faulty quick release on my first tranny but that one is no longer after the transducer disappeared somewhere between the c
cape and Bulwer.
When the rain stops I will get a few more pics up for you if you like.

[ZigZag]

Hi Marto,
I have a similar problem with my Haynes Signature 500 RF .. How far below your boat bottom do you have to go in order to get the best return ?

[nigelr]

Great post marto, I reckon this may be a problem with a lot of boats and various different transducers; my old savage has a pressed ali hull and the h'bird tranny is pretty rough at planing speed. I have gotten used to it though, and have built a sliding bracket but nowhere near as professional a job as yours! Think I'll give running the tranny a bit deeper a go.
Cheers.

[Horse]

I tried a lot of things before drilling a big hole and fitting a bronze through hull tranny. It certainly works well but its a step most are reluctant to make

[marto78]

A couple more side on pics:

Looking from under the motor with the bracket down.
DSC01151.jpg
And looking from the other side with the bracket up
DSC01152.jpg

[marto78]

Hi Marto,
I have a similar problem with my Haynes Signature 500 RF .. How far below your boat bottom do you have to go in order to get the best return ?

I think the destruction book says about 5mm below with a slight angle (or something or other I gave up on that thing years ago), but with mine because its only a tinny and bounces around a lot I found that I had to at least have the top of the transducer under water but to get less back spray I had to have the top of the mounting bracket under a fair way as well. I'm not real sure on exact measurements as it all sits below the water line and I just push it down until the pic is good and there is no more rooster tail, then lock it in place for the weekend.

[ZigZag]

Hi Marto...Thanks for the info. Really something to think about.

[Dignity]

Marto, great looking unit. I am not sure if there is something I missed but it appears you are relying on a wing nut to keep the unit from dropping down and putting stress on the cable. I would tap another hole at the maximum depth you would want to slide the inner tube down and put a bolt in there so that if the wing nut comes loose it can't drop any further than the bolt head if you get my drfit.

[whiteman]

That is soooo deep! And explains why I had no chance with it attached to the normal transducer mount. Your local engineer should make a few of those things and post them on this site. If I still had my 620 I would have bought one (and added Dignity's suggested mod).