Topic: Performance advantages to using HDSI and 2D xducer?

[Rotus623]

One of the reasons to use two ducers is obviously to protect the SI transducer. I was just wondering if you guys think that the smaller 2D ducer works as well or better than the larger HDSI ducer for 2d images while planed out?

Here are my observations. When I am doing most of my SI scans, I am between 6-10 MPH. Big surprise. Anyways, at this speed my boat is at a higher angle (the bow is raised). So to keep the ducer level from front to back while scanning I have to angle the rear of the ducer upwards. The issue here is that in order to get high speed 2D we need to lower the rear of the transducer to avoid cavitation.

In the case of SI, it is a no brainer that I will get crisper images if I raise my transducer and lift the back up higher than the front. The big question is, will the 2D ducer work as well as the longer HDSI transducer does at high speeds? Or possibly better?

[ITGEEK]

SI is not even supposed to work at speeds about 10mph, so
are you considering 10mph high speed?

High speed and crisp images usually don't
mix very well.
Some users have to go to the shoot through the hull
transducer to even get a depth reading while on plane.

I would assume that if you lower any transducer too low, and
run the boat on plane, that the transducer could actually get ripped off the boat.  I guess it could even affect the handling characteristics of the boat,
where the transducer is acting as a mini rudder.

I guess it all depends on how fast your boat can go, and how low
you put the transducer.

[rnvinc]

I'm pretty sure the 2d piezo is the same in the HDSI as in the XP 9 20...just in a different housing...

So the only variable is going to be ...the shoot thru is shooting thru fiberglass...

The digital depth comes from the 20° 200kHz frequency...I would think the xducer would have to be WAY out of level (sideways or fore/aft) before you would see any noticeable difference in the 2d echos or readings...

Rickie

[Rotus623]

Cool, thanks Rickie. I didn't think the angle of the ducer would affect the 2D sonar, just the SI. And you answered my question about the 2D piezo being the same in the cheaper 2D xducer. Didn't want to get all technical on ya, but here's what I mean.

When keeping the transducer ideal for planing speed , here's how it looks.


This is a little dramatic, but when my boat is not on plane, and when I am scanning with SI, here is the angle of the xducer.


Ideal transducer positioning during SI scanning.


But, that makes scanning in 2D while running impossible.


So, if I add a 2d ducer, I would angle the rear of the SI ducer upward to scan at the proper angle. Then I would just get my readings at planing speed from the 2d ducer only. I already have a spare 2d ducer. The true question is this, do you guys think that the angle change would improve image quality or be a waste of time?

[Rotus623]

Anybody catch my drift here?

[LocDown]

Even when you are going <10mph, the boat will eventually level out unless you are in and out of the throttle. Have you tried adjusting the trim.

[Rotus623]

Yea but I have to trim out so as not to interfere with the SI beams. Plus when my livewell is full back there it's even worse.

[ITGEEK]

I think you will get the best results with the
transducer as flat to the water as possible.

[Rotus623]

Yea me too. I got a xducer splitter so I'll let you know what I think.

[Trout Bum]

I have the (2) ducer setup. I get much better results (keeping bottom signal) with  this setup on plane than with just the SI ducer.

In my opinion, the dual beam ducer has a better water flow design and creates less air bubbles, etc, at higher speeds.

[Rotus623]

I have the (2) ducer setup. I get much better results (keeping bottom signal) with  this setup on plane than with just the SI ducer.

In my opinion, the dual beam ducer has a better water flow design and creates less air bubbles, etc, at higher speeds.

Thanks! This is just the kind of feedback I was looking for.  Plus with the 2 ducer setup you dont have to angle the HDSI transducer downward to avoid cavitation at planing speed. Did you keep your big ducer up higher for protection or at the level of the 2d ducer?

[Trout Bum]

Yes, my SI ducer is about even with the bottom of the hull. It is better protected that way.

You just need to make sure it has a clear view sideways in each direction.

[Humminbird_Greg]

Rickie is right: the same piezo is used for the 2D sonar in both the HDSi and 200/83kHz DualBeam transducers.

Rotus, are you looking to use an inside-the-hull mounted or an external transom mounted 2D transducer?

Trout Bum, it sounds like yours is an external transom mounted transducer, right?

[Rotus623]

Greg I am installing an external. I have an aluminum hull and haven't heard much about the alumaducer. Plus I already have an external 2d. I got crisp bottom readings with the hdsi ducer but had some engine feedback. I am installing a 22 amp hour standalone battery for the unit this weekend. I realized how important it is to have all these factors worked out. I think it will make my trips more successful.

[Trout Bum]

Rickie is right: the same piezo is used for the 2D sonar in both the HDSi and 200/83kHz DualBeam transducers.

Rotus, are you looking to use an inside-the-hull mounted or an external transom mounted 2D transducer?

Trout Bum, it sounds like yours is an external transom mounted transducer, right?

Yes, as my boat is aluminum, I don't have any choice.
I would sure like an internal like I had in my Ranger. I thought of installing a through the hull nut just can't get myself to drill around 1" hole through my hull.

[Humminbird_Greg]

I wouldn’t want to install a Thru-Hull transducer either Trout Bum.  I was just asking because I was thinking that Rotus was asking about an inside-the-hull transducer and I was pretty sure you were talking about an external transducer.  If Rotus went with an in-hull transducer he would have still had it angled when running at 10 mph and I did not realize if he knew this or not but now I understand with the external transducer.

[Rotus623]

Greg, I now have a stand alone battery, so that has helped with the  engine feedback. I mounted an old 2d transducer that I had laying around with the Y splitter to my 898.  I am getting decent returns now, but not much better than just running the HDSI ducer.

Here are my issues:

1.) By lifting the  HDSI ducer out of harms way, I have compromised the 7-10MPH SI readings. There is a lot of turbulence being read on the screen. Air bubbles look just like fishies, so this is a no go. I am thinking that I will have to lower the ducer back to its original spot.

2.) This leads me to my original concern. Adding the 2d transom mount transducer has proven to give me little to no benefit. Does anyone use the alumaducer? Would I expect to get fish returns at 20MPH or more with the thru hull ducer or just bottom readings? The standard alumaducer is designed for a flat hull. How would I use it with an angled keel??

Thanks in advance!!

[Rotus623]

So me thinks I answered my 2nd question. Called vexilar (alumaducer) and the rep told me that the only ducer they have is made for flat hulled aluminum boats, scouts honor   Bummer dude. He said "Well you could apply it on an angled deadrise/keel, but you would just have to know that it won't be as accurate......."   

C'mon dude.......

Anyways, I guess Ima have to finagle with this 2d ducer a bit more and see what I can figure out. Not quite ready to drill through my aluminum hull.

What is the product that eliminates the rooster tail and helps with turbulence?