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Old 29-04-2016, 17:02   #1
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ready to launch one last question

have 2 thru hulls, 1 for depth, 1 for speed wheel. both on same side of hull, just off centre line. speed wheel is slightly ahead and off to one side of depth sounder. last year had some issues with depth not quite reading right, thought could be loose wire or bad connections. Looking at hull, wondering if speed wheel should be behind depth sounder or does it make a difference because of possible turbulence??
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Old 30-04-2016, 01:08   #2
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Re: ready to launch one last question

Halifax Sailor,

I don't know what your bottoms are like in NS. If they are rocky, your depth sounder's readings will jump around a bit, and if it has a display of the bottom, it will look jaggedy or llumpy. When it is over mud, sand, & shell bottoms, the readouts should be smooth, and the graph, an almost straight line.

I could not tell from your post if it was unfamiliarity with how your depth sounder works, or if, as you suggested, it might be a loose wire. By all means, check all the connections, always a good deal, and may cure the problem, if there is one.

Ann
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Old 30-04-2016, 06:01   #3
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Re: ready to launch one last question

bottoms vary, mostly rock in good ol' NS. and seaweed, and shipwrecks, and lobster!!! what i am wondering is will the turbulence from the speed wheel, coming off the back of it, will that cause disruption to the freq out of the depth sounder? will it cause disruption in the readings? should i trade places with the two of them so depth is in front of the speed wheel?
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Old 30-04-2016, 06:24   #4
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pirate Re: ready to launch one last question

Switch them.. nothing to lose and you'll gain a few inches warning before you hit bottom..
But I doubt the paddle wheels having any effect as it off set.. even if not its miniscule.. you sure its not water temp fluctuations that's the cause.. and those bludi fish that seem to love the 'Pulse'..
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Old 30-04-2016, 06:43   #5
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Re: ready to launch one last question

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Originally Posted by Halifax Sailor View Post
bottoms vary, mostly rock in good ol' NS. and seaweed, and shipwrecks, and lobster!!!
I have never hauled anchor to find the flukes fouled by lobster.

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Old 30-04-2016, 08:08   #6
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Re: ready to launch one last question

My depth instrument often reads the tops of the seaweed. Scares the h*ll out of me. Sometimes its just better to turn it off. I miss the days when I had no depth instrument...I trusted the charts, myself, and looking over the side. And rarely hit anything.

If you never hit a rock or run aground, then most likely you never left your dock.
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Old 30-04-2016, 10:28   #7
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Re: ready to launch one last question

Quote:
Originally Posted by Halifax Sailor View Post
have 2 thru hulls, 1 for depth, 1 for speed wheel. both on same side of hull, just off centre line. speed wheel is slightly ahead and off to one side of depth sounder. last year had some issues with depth not quite reading right, thought could be loose wire or bad connections. Looking at hull, wondering if speed wheel should be behind depth sounder or does it make a difference because of possible turbulence??
For what it may be worth? I had a Sitex with a transducer with a wheel. The wheel was aft. But if you have some separation I doubt it matters?
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Old 30-04-2016, 11:25   #8
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Re: ready to launch one last question

Quote:
Originally Posted by Halifax Sailor View Post
bottoms vary, mostly rock in good ol' NS. and seaweed, and shipwrecks, and lobster!!! what i am wondering is will the turbulence from the speed wheel, coming off the back of it, will that cause disruption to the freq out of the depth sounder? will it cause disruption in the readings? should i trade places with the two of them so depth is in front of the speed wheel?
Ideally,you should have no "protuberences" closer than 2 ft ahead of any depth/fishfinder transducer. If off to one side ,you can get by most times.
A speed paddlewheel could cause enough water turbulence to affect your ducer. If you can reverse them easily-do so.
Air bubbles entrained in the water passing over a t-ducer will cause erratic & sometimes breaks in the bottom echo. Ideally,a transducer should be located 1/3 or so aft from bow,to ensure it stays in "unbroken water" caused by the hull pitching into a sea & either lifting ducer clear of water or the hull "capturing" air as it crashes back after a sea.
If your sounder works good in smooth water & gets erratic in rough water,this is most likely your problem.
Note: your sounder should "break up" when crossing a wake or strong current or,when reversing.
It will pick up currents & weeds,etc. if it is any good.
Experience is the best teacher for a particular vessel.Run sounder as often as you can & always while powering, to get familiar with it-same with radar.
If your sounder is always erratic-stopped,smooth water,slow speed-you probably have an electrical problem. If the display shows bottom,but is "noisy" in water column,look for an open shield on ducer cable & or interference from other electrical eqpt. Refrain from bundling a ducer cable with other wiring,as it may pick up interference.
Try your sounder while on the hard. It should pick up a solid surface/plywood,etc. within 2 ft or more of ducer's face. Do not paint ducer & scrape face clean before launch. Yeah-I know there are special ducer paints-BS IMHO. Put your hnd on ducer face-can you feel the flex of ducer face every TX pulse. It moves,just like a speake cone. Would you paint a speaker cone? Would a speaker be a bit "muffled" by painting it?
Run you sounder daily-keeps fouling minimal.
Through hull ducers-check for solid contact to un-cored hull,paint buildup on that area outside hull, ducer box full of fluid if used. The ducer has to flex that bit of hull between it's face & the water to work. Anything "mushy" between them will reduce or stop it from working.
Cheers/ Len
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Old 30-04-2016, 11:49   #9
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Re: ready to launch one last question

I experienced turbulence with my sounder when it was two feet to he side of my outboard. If you have a paddle wheel for your speed. The transducers may very well pick up bubbles from the spinning wheel if it is mounted forward of the transducer. If you can conveniently do so, switch them. If not try another back up application (like off your gps or chart plotter). That could provide a backup until you can remedy the position issue. The best would be switching the mountings to opposite sides of the hull and moving the transducer forward but that might require another thru hull that you may not want. Best of luck to you whatever you choose to do.
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Old 30-04-2016, 12:20   #10
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Re: ready to launch one last question

Quote:
Originally Posted by hamburking View Post
My depth instrument often reads the tops of the seaweed. Scares the h*ll out of me. Sometimes its just better to turn it off. I miss the days when I had no depth instrument...I trusted the charts, myself, and looking over the side. And rarely hit anything.

If you never hit a rock or run aground, then most likely you never left your dock.
No need to turn it off-it's only showing what's below it. The rock you hit is farther forward
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Old 30-04-2016, 14:56   #11
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Re: ready to launch one last question

IMO, the turbulence induced by a paddlewheel is trivial compared to the general turbulence of flow along the hull. Further, turbulence per se should not interfere with the acoustic pulse nor the reception of the return signal. Entrained air can do so,and as others have said, especially when pitching a bit, this is a likely source of problems, but will not be caused by the paddlewheel.

Keep looking!

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Old 01-05-2016, 14:43   #12
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Re: ready to launch one last question

The answer to the OP question is YES it matters according to most manufacturers. It is preferred that the depth not see turbulent water and installation for mine noted paddle-wheels. Lock up the paddle wheel or remove it if you have a dummy plug and see if it makes a difference.


For what its worth, I consider depth way more important than the speed. I get speed from the GPS. The paddle wheel is off by up to 1.2 knots. Its not an instrument I would replace after the lightening hit.
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Old 01-05-2016, 16:07   #13
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Re: ready to launch one last question

Quote:
Originally Posted by Jim Cate View Post
IMO, the turbulence induced by a paddlewheel is trivial compared to the general turbulence of flow along the hull. Further, turbulence per se should not interfere with the acoustic pulse nor the reception of the return signal. Entrained air can do so,and as others have said, especially when pitching a bit, this is a likely source of problems, but will not be caused by the paddlewheel.

Keep looking!

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Old 02-05-2016, 08:48   #14
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Re: ready to launch one last question

pulled into a south florida marina at high tide one evening. Several days later time to go Very Low Tide and could not get out of the slip. The dock master was very understanding and allowed me to delay my departure. Depth gauge was not helpful at all
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Old 02-05-2016, 22:44   #15
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Re: ready to launch one last question

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I get speed from the GPS. The paddle wheel is off by up to 1.2 knots. Its not an instrument I would replace after the lightening hit.
gps speed (over land) and speed through water are 2 totally different things and a difference is expected and is meaningful. (the difference between them is the current in knots...)
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