[blakeyoung]

I have a Catalina 22 on which I am interested in installing a chartplotter/sonar system. I have been idly looking here and there but am now getting serious and would like to make a purchase in the next several months.

I will admit that this is rather new territory for me, so forgive my ignorance. There appear to be an overwhelming number of options and potential setups.

I am looking hard at the Garmin echoMAP 50dv. The stock unit comes with a transom/trolling motor mount, but I am likely going to switch this out for an in-hull. I am looking at the Airmar B117. There are at least two local boat shops with whom I've done business who can do the in-hull install. Assuming that this is a decent setup, I had a few questions regarding chartplotters, tranducers, etc.

1) With a chartplotter system like this, is your speed calculated via GPS? I would like to have real-time speed information, but I didn't know if I needed a transducer with speed functionality, such as this. I'm guessing this one can be used on non-GPS systems to calculate speed by measuring how fast water is moving under the hull?

2) Would a tilted element transducer be better? The whole concept of a tilted element transducer is a little confusing to me. Is the transducer angled to offset the slant of the hull? That is, if the transducer is flush with the hull, instead of pointing at an angle in front of your boat, the beam is angled downwards to keep it perpendicular?

Thanks in advance.

 

[CharlzO]

For the first, yes, it's using the GPS to calculate your speed. However, if you want to add things like water temperature, and have a more exact speed constantly (some plotters only update every second or two, which is fine for some people. Other people like knowing every millisecond), then you would need something like you linked.

Many people feel that a thru-hull transducer is more accurate. However, depending on just how vital an exact accuracy and over 200' deep goes, could make a case either way. Some seem to be less accurate past 200' from what I've read, but it likely depends on the unit and if it is installed without air in the medium, etc. I use a shoot-through-the-hull style (like this) with my chartplotter, and it's just as accurate as other people around me on the lake, and will easily read the 450'+ depths in the middle of the lake. And I didn't have to have any extra holes drilled

 

[blakeyoung]

Haha, yeah, I will admit the thought of drilling a hole in the bottom of my boat does make me a little weak in the knees.

This may be a dumb question, but the shoot-through-the-hull transducer will not be able to give you speed or temperature readings will it? Are these pretty much only used for depth? Honestly I don't really need speed or temperature readings, but part of me feels like if I'm going to go through all this trouble, then what the hell I might as well go all out.

If I did buy a transducer that could calculate speed, I guess it would depend on the particular display you're using whether or not it would show speed from the transducer in addition to the speed from the GPS. I guess I would have to ask Garmin what this echoMAP model would do.

 

[CharlzO]

Correct, they won't give you water speed or temperature, just depth (and fishfinding). In my case, I was happy with the GPS speed instead, and if I want to know if the water is cold, I'll stick my toe in lol. That, and the cost of the multi-function thru-hull was a little more than I wanted to put into something I was already putting money into. But it depends on each persons location, sailing habits, etc.

I do believe you're correct that it would be unit-dependent. I never looked into it, since i went the route I did. I'm sure Garmin can tell you, or even perhaps download the owners manual / installation for that unit from the web and see if it mentions setting the inputs based on what transducer, and so forth.

 

[jerryRiggin]

Navionics has a free app that you can try for your iPhone, iPad, Android phone, tablet, etc. for chartplotting and GPS. You can purchase a Vexilar sonar unit for the depthsounder/fishfinder mode. They work together. This works really well and is way more affordable than any other option.

SonarPhone | Navionics