Lowrance Hook 2 4x fitted in-hull as depth gauge

Need some trouble-shooting help.

I needed to replace my 15-year old depth sounder with something that would work reliably at shallow depths, most importantly, when the depth gets below 2m and I am about to run aground. Also, I don't like putting holes in the hull, so I wanted an in-hull sounder that would shoot through the hull.

In my previous boat (Austral 20), I fitted a Lowrance Hook 2 5x inside the hull, and it worked very nicely, especially in shallow water. Being a cheapskate, I thought I would try again with the Hook 2 4x, which has a smaller screen and a smaller bullet, and it is cheaper.

At this stage, you might rightly point out that the Hook2 bullets are designed to be mounted in the water off the back of the transom of a tinny. They are not designed to shoot through hulls, and their primary purpose is finding fish, not measuring depths, although they do the latter function as part of the former. But, my experience shows that you can mount a Hook 2 5x in-hull and use it to get the depth in shallow water. The 5x uses a more sophisticated sonar system, which may make the critical difference in shallow water.

My problem is that the Lowrance Hook 2 4x is not getting reliable readings at shallow depths. It blanks out at about 3m (?) depth, which is just when things get interesting. I had glued the bullet to the inside of the hull with some Fixtech, but I took it off (and slightly damaged the casing) and re-positioned it with some blue-tack to try to improve it. I've put it in the bilge, a little forward of the old through-hull fittings, in front of the keel, and I cleaned the area with a wire brush and a wipe-down before fitting. Now, it turns on and fires up, but I get no depth readings at all. I only tested it by sailing around inside Manly Harbour at low tide, so probably did not get deeper than 3m. I have yet to see what happens in deeper water. I might have to dangle the bullet off the boat to check it, but that would mean undoing the wiring, routing and soldering.

I'd like to know if this is a problem with the Hook 2 4x unit or my installation. If it is a problem with the unit, I might just have to bite the bullet* and get a better one, although I'd like to know it will work before buying it. Other problems could be the blue-tack or something in the hull that interferes with the signal.

Has anyone else had experience with mounting a Lowrance Hook2 4x as an in-hull depth sounder?(* apologies for the pun)

Have one (Hook) Love it.
Sail in an area where just off the channel means trouble.
Depth alarm set at 2 metres and hasn't let me down yet.
mine is a pretty standard installation, with transducer pressed into refrigeration putty.

I'd like to know if this is a problem with the Hook 2 4x unit or my installation. If it is a problem with the unit,
My guess is the installation or the unit. The Hook sounder itself is about as robust as they come.

but I took it off (and slightly damaged the casing)

any photos of this?

Gary

Even faster way is put transducer in heavy clear fish bag with water in taped up, move it around while someone watching screen, clear bag also ensures u holding at right angle when u finally find the spot, take out of bag dry off, then clear silicon it down at correct angle ensuring no air gaps in silicon

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nswsailor said..
So just going on from here, with the latest tech, what is the best sounder/fish finder/plotter at the moment.
I'm looking for a 7" screen, GPS, NEMA and charts. Transducer to be positioned in hull.
Not looking for side scan.

You might have to put up with side scan.

www.chsmith.com.au/Products/Lowrance-Hook-Reveal-7-50-200-HDI-Combo.html

Gary - photo of damage, showing the bottom face. The light stuff is some blue-tack that got stuck in the crack. As far as I can see, the crack does not go all the way through the bullet wall. (PS I don't have short thumbs - its a perspective thing).

I tried it today and got no readings at all. Tried blue-tacking it in several locations in the bilge, but only occasionally got a faint smudge on the display when I pushed it down really hard with my hand, and no numbers on the display. I'll check for a loose connection with the head later (thank you, hindsight), but if that does not work, the unit is a dud.

Success!!!

Thanks for your suggestions. The key was making a wet well inside the boat, which I did with a Sistema food container.

For photos and further details, please see my blog (which I have finally updated) here theboattinkerer.blogspot.com/2020/06/episode-29-depth-gauge.html

If you are interested, see also my backlog of posts here
theboattinkerer.blogspot.com/2020/06/episode-28-leaky-windows.html
theboattinkerer.blogspot.com/2020/06/episode-27-broken-rudder.html
theboattinkerer.blogspot.com/2020/06/episode-26-wobbly-prop.html
theboattinkerer.blogspot.com/2020/06/episode-25-sold-and-bought.html

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troubadour said..

Achernar said..
Success!!!

Thanks for your suggestions. The key was making a wet well inside the boat, which I did with a Sistema food container.

For photos and further details, please see my blog (which I have finally updated) here theboattinkerer.blogspot.com/2020/06/episode-29-depth-gauge.html

If you are interested, see also my backlog of posts here
theboattinkerer.blogspot.com/2020/06/episode-28-leaky-windows.html
theboattinkerer.blogspot.com/2020/06/episode-27-broken-rudder.html
theboattinkerer.blogspot.com/2020/06/episode-26-wobbly-prop.html
theboattinkerer.blogspot.com/2020/06/episode-25-sold-and-bought.html

Regarding the leaky windows, did you change the glazing rubber? I have the same windows on my Cav 28 and looking to replace the glazing rubber which has also been referred to as the glazing wedge.

Hi troubadour,

No I did not replace the rubber gasket (glazing wedge?) around the glass (acrylic?). I smeared some FixTech around the edges, but there appear to be some small leaks remaining. I'd have to take the windows apart, again, for a closer look, which is now a long way down the list of things to do. My initial thoughts, however, were to remove the rubber and glass/acrylic, clean out all the old gunk, repaint the aluminium black, and re-fix the glass with FixTech window sealant. Or, find the right sized rubber gasket. It would be a considerable project, and I could not go sailing as long as the windows were out of the boat.