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#1
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Horizontal Depth Gague?
I know this this might seem daft, but, I was idly wondering whilst gazing
at my carnation shaped propeller if a second, narrow angle depth gague with it's transducer shooting horizontally forwards just below the water surface, would give advance warning of an impending prop repair? (alarm set at, say, 40 feet). How would the sonar cope with seeing (hearing) the water surface and waves? would 2 sonars interfere with each other? Steve |
#2
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Horizontal Depth Gague?
like this?
http://www.farsounder.com/technology..._explained.php "lomaxelectrical" wrote in message ... I know this this might seem daft, but, I was idly wondering whilst gazing at my carnation shaped propeller if a second, narrow angle depth gague with it's transducer shooting horizontally forwards just below the water surface, would give advance warning of an impending prop repair? (alarm set at, say, 40 feet). How would the sonar cope with seeing (hearing) the water surface and waves? would 2 sonars interfere with each other? Steve |
#3
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Horizontal Depth Gague?
That looked extremely promising until I saw the price. $55,000!!!!!
I think I will wait until Walmart stocks them. Jeff Morris wrote: like this? http://www.farsounder.com/technology..._explained.php "lomaxelectrical" wrote in message ... I know this this might seem daft, but, I was idly wondering whilst gazing at my carnation shaped propeller if a second, narrow angle depth gague with it's transducer shooting horizontally forwards just below the water surface, would give advance warning of an impending prop repair? (alarm set at, say, 40 feet). How would the sonar cope with seeing (hearing) the water surface and waves? would 2 sonars interfere with each other? Steve -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#4
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Horizontal Depth Gague?
"Glenn Ashmore" wrote in message news:N4GFb.9775$JD6.8424@lakeread04... That looked extremely promising until I saw the price. $55,000!!!!! Echopilots are a bit more reasonably priced. But they are best suited to sailing boats - if you have a carnation prop I take it you are going quite fast... http://www.echopilot.com/ |
#5
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Horizontal Depth Gague?
Not fast at all, less than 5 mph. I was about 20' west of the moorings round
the back of the island north of Belle Isle on Windemere. (in-case you happen to find yourself there ;-) The boat came to a dead stop. I think the skeg or the leg jammed against a rock as the prop, still turning, tried to drill its way through the side of it. It's amazing how much damage can be done in just a second. I also caught my spare prop, leaving the middle of the Brock Hole (?) jetty south side. 2 props in one day, I hear the cheers from speed limit supporters! This was Easter this year, about a week before the TV report about how low the water is on Windemere this year... "Ric" wrote in message ... "Glenn Ashmore" wrote in message news:N4GFb.9775$JD6.8424@lakeread04... That looked extremely promising until I saw the price. $55,000!!!!! Echopilots are a bit more reasonably priced. But they are best suited to sailing boats - if you have a carnation prop I take it you are going quite fast... http://www.echopilot.com/ |
#6
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Horizontal Depth Gague?
"lomaxelectrical" wrote in message ... Not fast at all, less than 5 mph. I was about 20' west of the moorings round the back of the island north of Belle Isle on Windemere. (in-case you happen to find yourself there ;-) Quite often actually - but normally on a windsurfer so not much worry! |
#7
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Horizontal Depth Gague?
That collision avoidance scanner looks interesting. Wonder what it will
cost and if they will make a smaller unit like their FLS Bronze unit. I am not so concerned about the forward bottom profile. I want a device that will detect anything between the surface and say 10' deep out to a distance that will give time for reaction. The Interphase Probe would probably work but the Echopilot looks to be a lot more sophisticated and easier to interpret. Ric wrote: "Glenn Ashmore" wrote in message news:N4GFb.9775$JD6.8424@lakeread04... That looked extremely promising until I saw the price. $55,000!!!!! Echopilots are a bit more reasonably priced. But they are best suited to sailing boats - if you have a carnation prop I take it you are going quite fast... http://www.echopilot.com/ -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#8
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Horizontal Depth Gague?
Yes, it looks great and just the ticket, but £44000 will buy a lot of new
props. I was thinking of adapting an old fish finder I have. The image shows the sender at the bow of the boat, which is fine for displacement craft. It would have to be mounted at the stern for planing hulls, and it would see the boat hull. Would the setup be reliable with the 'bounce' and the ever changing angle of attack to the water. What about rough seas? Steve "Glenn Ashmore" wrote in message news:N4GFb.9775$JD6.8424@lakeread04... That looked extremely promising until I saw the price. $55,000!!!!! I think I will wait until Walmart stocks them. Jeff Morris wrote: like this? http://www.farsounder.com/technology..._explained.php "lomaxelectrical" wrote in message ... I know this this might seem daft, but, I was idly wondering whilst gazing at my carnation shaped propeller if a second, narrow angle depth gague with it's transducer shooting horizontally forwards just below the water surface, would give advance warning of an impending prop repair? (alarm set at, say, 40 feet). How would the sonar cope with seeing (hearing) the water surface and waves? would 2 sonars interfere with each other? Steve -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#9
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Horizontal Depth Gague?
Yes. I did it with an older Paper chart recorder with lots of power. I put
the TRansX at about 45 degrees under the bow in front of the keel. It needs interpretation just like radar though. You compare the bottom of the normal sounder and the FWRD looking. When the slope of the bottom gets steep and is less than or equal to the depth of the normal trace, you have an obstruction approx the depth read in front of you on the frwrd modded trace. This is so because the _rate_ of _change_ from the 45deg trans~ is high when the bottom is shoaling in front of you; ie, each foot of frwrd movement is approx the same as the rate of depth change when there is an object in front of you at your depth. So, when the trace is very steep it is because your forward motion is what causes most of the change in the trace, assuming the obstruction is solid and large enough to provide most of the echo. If there is no obstruction the rate of change of the trace is very low or nill. A string and a fixed point will show you all possible positions for a single echo. ASIDE: i found that using the standard sounder at twice the expected depth allows you to read the second echo (looks like a second bottom below the actual bottom trace). the rate of change of the second echo is similar but not as sensative as the modified transducer trace. It will steepen rapidly when the bottom is shoaling quickly. when the two traces meet you have an obstruction right in front of you at the depth indicated. I suspect it is a consequence of the wide cone of radiation from the transducers that allows this. All you read on a simple depth sounder is time of return on the Y-axis and elapsed time on the X-axis. If the sounding is ahead or below it gives the same return time. Those little dots below the surface line are reflections that came back a little later than the ones straight down and that are likely from rocks at an angle in front or aside the lone of travel... you can't tell which! that is unless you use the second echo becasue it has the element or rate of change asociated with it so any change to shalower includes you frwrd change as well so the line steepens with forward movement to a fixed echo...presumably at lower depth. NOW, if i had time i would edit this down to the 4 lines necessary to convey my thoughts...or even the one word..."YES". rick On Mon, 22 Dec 2003 17:18:57 +0000 (UTC), lomaxelectrical wrote: I know this this might seem daft, but, I was idly wondering whilst gazing at my carnation shaped propeller if a second, narrow angle depth gague with it's transducer shooting horizontally forwards just below the water surface, would give advance warning of an impending prop repair? (alarm set at, say, 40 feet). How would the sonar cope with seeing (hearing) the water surface and waves? would 2 sonars interfere with each other? Steve -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/ |
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