depth finder puck

[trainmanjess]

hello all

I recently got a hummingbird depth finder... I placed the puck inside the cabin on the floor as close to the bow as possible... it seems to be giving me a less than 1 foot reading when in the water... I cannot figure out why.... I paced it in the toilet ring grease and made sure there is no air pockets in the grease.... i am at a loss about this....

need help figuring this out

sincerely
Jess

 

[kito]

When you say "floor" I hope you mean directly on the hull and not any kind of liner. Also, you should experiment with placement first before setting it. You putting it as close to the bow makes me think it's not facing straight down and may not even be below water level. Fwiw, mine is located slightly starboard and aft of the keel.

 

[Anonymous 121765]

T,

Never try & mount a puck in the bow man.
Your cockpit area stays in the water, your bow does not. Transducers do NOT like air.

Put it as close to the centerline as possible somewhere under your companionway, this & the cockpit is the best & deepest part of your hull, that's the reading that is most important.

Take a zip lock bag I/3 full of water. With the unit turned on & located on the bottom of the bag, find a spot that gives you a good read against your inside hull. If there are any air pockets in the hull you will not get a solid read. It has to be laying flush with the inside hull or if any air is underneath, you'll get the same response as when it was at the bow.

You don't have to epoxy it in, a decent caulk will work just as well (NO AIR POCKETS IN THE CAULK). You will know when you're in the right spot.

You're now located just after the keel & this is where it needs to be pal. We're not building a watch, were looking for a sound blip bouncing off the bottom. If you have grass under you, this may also give you a false read (this is normal) but, not to fret.

I've put alot of these in but, whoever told you to locate it at the bow, needs additional training. Alot of powerboaters make the same mistake of locating on the bow or off their transom. It can however, really be a breeze to locate properly.

When relocated, there should be a depth offset option in your bottom finder. Let's say you can closely judge the difference between your keel depth & where it is level is on your hull (the water line), If you can measure or calculate how deep you float as opposed to the keel bottom, that's the offset you punch into your bottom finder, If the difference is a foot, that's your offset.

Let's say you draw 4 feet. You then find that the true distance from the waterline to keel is a foot less, you offset will be MINUS 1 foot (a three foot difference, not four). Now you have the true depth of your keel. No more guess work.

Let us know how this works out for you.

CR

 

[Bill Roosa]

Forward of the keel is an important place for a depth finder. If you put it aft of the keel then you tend to run aground before the depth finder can sense the problem.
also check the "keel offset" since the puck is probably at the water line there is the provision to adjust the control head readout to account for how deep in the water the puck actually is. You also have to decide if you want the control head to read water below the keel or actual depth. "keel offsets" are positive for reading the actual water depth and negative for reading water below the keel.
if the puck is 1' below the waterline and the keel is 5' then:
to read the actual depth set keel offset to +1
to read the depth below the keel set the keel offset to -4

 

[Ward H]

What Bill said. I measured the water depth at the transom water line and set the gauge offset to match that depth. I then set the shallow water alarm to sound at my draft depth plus one foot.

 

[Indysailor]

If you're hoping to keep from running aground because you have your depth finder forward of your keel, I say good luck with that.
I just mounted a puck from a hummingbird 150, shooting through the hull on my boat. Mounted with plumbers putty- works nicely. Sanded the hull so that the grime and dirt are gone, scrubbed it clean and wiped with acetone for good measure.

I'm not sure what your cabin floor is, but you do need to make sure there's nothing between the transducer and the water but the hull.

http://forums.sbo.sailboatowners.com/showthread.php?t=165843

 

[Anonymous 121765]

Forward of the keel is an important place for a depth finder. If you put it aft of the keel then you tend to run aground before the depth finder can sense the problem.
also check the "keel offset" since the puck is probably at the water line there is the provision to adjust the control head readout to account for how deep in the water the puck actually is. You also have to decide if you want the control head to read water below the keel or actual depth. "keel offsets" are positive for reading the actual water depth and negative for reading water below the keel.
if the puck is 1' below the waterline and the keel is 5' then:
to read the actual depth set keel offset to +1
to read the depth below the keel set the keel offset to -4

Bill,

Do you really believe that a puck mounted transducer before or after the keel will make a difference when going aground?

Let's say you're going @ 5 KTS, that's 1.15 MPH. Now Divide that by 60 (min/sec) and in one second, you can gain 1.6866666721 feet/second. Now let's say my aft location is 10 foot to the rear of yours. Well, that equates to around 16.86 feet of forward travel in just 10 seconds. Do you believe the difference in the location between a front of the keel mount & an after keel location will make a difference at this speed? Then I must ask, how good are your reaction times? I think KNOT quick enough, I know mine are not. It's the course steered that got you here, not the puck location.

If you don't agree, you're a better man than I Gunga Din. I always thought the game plan was not to go aground. The "Prudent Navigator" should take care to avoid this. Traveling at 1.68 feet per second @ 5KTS(as a constant), by the time you react, it will be too LATE & you are most assuredly aground.

It's not the speed or the science man, it's water & the depth or, the lack thereof.

CR

 

[woodster]

Bill,

Do you really believe that a puck mounted transducer before or after the keel will make a difference when going aground?

Let's say you're going @ 5 KTS, that's 1.15 MPH. Now Divide that by 60 (min/sec) and in one second, you can gain 1.6866666721 feet/second. Now let's say my aft location is 10 foot to the rear of yours. Well, that equates to around 16.86 feet of forward travel in just 10 seconds. Do you believe the difference in the location between a front of the keel mount & an after keel location will make a difference at this speed? Then I must ask, how good are your reaction times? I think KNOT quick enough, I know mine are not. It's the course steered that got you here, not the puck location.

If you don't agree, you're a better man than I Gunga Din. I always thought the game plan was not to go aground. The "Prudent Navigator" should take care to avoid this. Traveling at 1.68 feet per second @ 5KTS(as a constant), by the time you react, it will be too LATE & you are most assuredly aground.

It's not the speed or the science man, it's water & the depth or, the lack thereof.

CR

i thought 5 knots was 5.73 mph is i wrong

 

[kito]

If you run aground with the puck in front or aft of the keel means your just not paying attention. Your talking what.....maybe 6 feet?

 

[Anonymous 121765]

Wood,

You're missing the point pal. You're quibbling about 100's of a mile per second. Does that sound as a just argument in puck placement & going aground?

If you feel this make a major difference, I would luv to sail in your waters man.

CR

 

[woodster]

that figures out to about 6.83 ft per second and i can assure you that it makes no diff when you run aground...

..i had a lowrance depth finder one time on a powerboat in beaufort sc and had it set for 2 ft alarm we were running out to the broad river to go fishing on an outgoing tide ....well you guessed it we ran aground just as the alarm went off and we had to jump out and get the boat of the bottom or stay all day till next high tide and we just couldn't do that as we didn't have enough beer in the cooler to last that long we got off but it was a bear of a time so anytime you want to go fishing with me just say the work i have the alarm set lol

 

[Anonymous 121765]

WOOD,

I've spent nights aground man, it SUCKS.

I feel your PAIN!

CR

 

[Stu Jackson]

It's the course steered that got you here, not the puck location.

Great math and analysis.

I always, always wonder why skippers think that their depth sounders are there to tell them when the water is too thin for their boats.

NOT!

They're there to CONFIRM what your CHARTS should be telling you. It is another means of navigation, NOT a warning signal.

Read Chapmans's. Please.

Some of us are old enough to recall when there were no depth sounders, or they were too expensive for us recreational boaters. I sailed our Catalina 22 for many years without one, SF Bay, estuaries, The Delta (one of those places is where the proverbial "If you haven't run aground you're lying about being there!" places), and lake sailing. The Catalina 25 had one, but it was off or useless most of the time, 'cuz it was one of those spin around the ring non-digital types - pretty useless.

cr is right, it's sooo simple. Ain't math great?:dance::dance::dance:

 

[Kermit]

Interesting thread. I just put my H260 back on the trailer at Smith Mountain Lake, VA. I'm accustomed to sailing in 25-30'water. Here 100' or more is the norm. I never thought I'd get antsy in 25' water. But I sure did this week!

 

[Anonymous 121765]

Kermit,

Anytime the depth gage shows a shallow setting & you notice this,
be happy, as that means you are watching it so, your chances of going aground are somewhat diminished.

I have a slight different take on Stu's saying about, ""If you haven't run aground...... I say, you've haven't been AGROUND, you haven't been AROUND"! Until this day, I have two shoals named after me in Tampa bay that I always ran aground on. My friends STILL use these as waypoints. Sadly, they use my name.

Another saying to keep in mind is," When the boat's draft exceeds the water's depth, You are most assuredly AGROUND".

Gee, I wonder why that is.............? Sometimes, it's GOOD to be BAD.

CR

 

[Charlie Jones s/v Tehani]

I use the depth gauge primarily when feeling my way into an anchorage, and then to let me know how much rode to lay out. Otherwise, It's mostly turned off, and I'm on the charts.

Of course the charts are not always correct. Spent the night aground in west Fla one night because the buoys had been renumbered since I went through the last time. Got off ok next morning, thanks to Google maps on my IPhone

 

[trainmanjess]

hello all

let me say, thank you all for your help... a friend and I installed the puck in the bow, just below the water line in my boat, because I have a full keel boat... also the transom does not sit in the water either.... the keel runs the full length of the cockpit... we tried back under the cockpit area, but could not get a reading.... we had a reading when we set it under the bow at the dock..... then we went sailing and that's when I noticed it was reading less than 1 ft on the monitor... I rechecked the puck, it is still holding and mounted in place where we put it....later back at the dock I rechecked it again, and it was still reading less than 1 ft for the depth.... I placed it up near the bow inside the cabin on the outer hull, under the V-berth....

I am at a loss.... I did remove it and set it in the water while at the dock, and it gave me a true reading of the depth there.... then replaced it back into the boat.... and it showed less than 1 ft again.... I am at a loss on this....

sincerely
Jess

 

[Crazy Dave Condon]

First, I use to tell my customers look at the color of the water which in many cases if brown, guess what, you are close to running aground. Depth finders help but another suggestion if close to shore, I told my customers to look at the lay of the land as if it is shallow coming out to the water edge, then expect the depth to be shallow but if the angle of the shore is deep, the expect it to be deeper close to shore.

where the boat is sitting at the dock, take a line with weight by the boat to determine what the actual depth is. Then determine depth of the boat from waterline to the part of the hull where the puck is and subtract that from the actual water depth. There may be several things going on. Possibly air bubbles in the glass to give you false readings. The next is the area where the puck was attached was not prepped first which is sanding smooth and cleaning with acetone to make sure all debri and chemicals and so forth are removed. What ever you are using to secure the puck, you have to make sure there are no air bubbles between the puck and the bottom of the hull. As for attachement, never use a two part epoxy as it is fiddlesticks trying to remove the puck and it could be damaged too.

Is there an offset screw which to readjust the puck?

With this, go back and report what you find and lets go from there.

I grew up around Smith Mt. Lake and in places it could be 100 feet and then immediately 2 feet. Again the lay of the land determined suspected areas that were shallow.

 

[dlochner]

hello all

I recently got a hummingbird depth finder... I placed the puck inside the cabin on the floor as close to the bow as possible... it seems to be giving me a less than 1 foot reading when in the water... I cannot figure out why.... I paced it in the toilet ring grease and made sure there is no air pockets in the grease.... i am at a loss about this....

need help figuring this out

sincerely
Jess

As others have mentioned the puck needs to be attached directly to the hull. The hull can not be cored, it must be solid fiberglass, no voids or bubbles in the layup.

I would question using wax to attach it. If the sound waves won't pass through balsa core, they probably won't pass through wax. Try placing the puck in a bag of water and try it in different places.

The depth sounder needs clean water, i.e., no turbulence to work effectively. In front of the keel as close to center as possible and pointed straight down, not angled off to one side.

 

[mrducks]

Having not yet installed my new Humminbird PiranhaMAX, I read this thread with interest, and find many of the posts contradict the instructions provided by the manufacturer. Am I to believe that after 30 years of sales of the units, they don't know how, or where it should be installed?

My manual states:
The installation requires slow-cure two-part epoxy. Do not use silicone or any other soft adhesive to install the transducer. Do not use five-minute epoxy, as it has a tendency to cure before the air bubbles can be purged, thus reducing signal strength.

Yet I read here,
...As for attachement, never use a two part epoxy as it is fiddlesticks trying to remove the puck and it could be damaged too.
...Mounted with plumbers putty- works nicely.
...From the original post - "I paced it in the toilet ring grease and made sure there is no air pockets in the grease"
...You don't have to epoxy it in, a decent caulk will work just as well

I want to do the job correctly the FIRST time, and although I generally learn something from most threads, the number of totally contradictory opinions here on both mounting and location, are all contrary to the manufacturer's instructions that are easily understood and rational.

Dave