depthsounders

B

bobflydrum@hotmail.com

New member
what type of depthsounder should i buy--i would prefer a transducer that mounts inside the hull--do these work on c dorys--i looked at one that said it would not work on a cored hull--any suggestions are appreciated

bob
 
bobflydrum@hotmail.com":2fl4irje said:
what type of depthsounder should i buy--i would prefer a transducer that mounts inside the hull--do these work on c dorys--i looked at one that said it would not work on a cored hull--any suggestions are appreciated

bob
Click to expand...

It will work BUT!! you have to cut a hole in the deck layer, remove the balsa core then epoxy the shoot through hull transducer to the hull layer. With no air pockets :wink: Transom mount is lots less B/S :mrgreen: :beer
 
There are a couple other advantages of the transom mount transducers: you can also get one with a temp sensor and a speed paddlewheel. We've had the thru-hull transducers and a through-the-hull transducer on previous boats, and I see no difference in performance. And, no cutting. :D

Our trimaran had a spot just for a transducer that wasn't cored... anyone know if C-Dory made any provisions like that?

Best wishes,
Jim B.
 
I blieve that most of the CD 22's had a solid area in the center aft by the drain plug--sump where the bilge pump is, which is solid glass. The CD 25 again where the bilge pump is, just aft of the fuel pump, and the Tom Cat 255 in the STb hull all of the way aft. But each of these areas, means moving the builge pump.

I don't use the paddle wheel sensors, because they are only good for measuring current--the GPS is a more convient speed indicator. Also some engines have a speed function on their digital guages (usually a piot tube, and not real accurate.

I use transom depthfinder sensors, for the boat I keep in the water, but mount a block of Starboard on the transom, then screw the transducer to this piece of Starboard. I do use the water temp function of the transducer.
 
I had such bad luck with the transom transducer on my previous boat that I was insistent on a shoot-through transducer for the TC (there is a core-free spot molded into one sponson for this purpose.) I absolutely love this transducer. However, I am adding a dedicated speed paddle wheel & temp module so I can measure current and water temp.

All that said, I have not heard many complaints from other Brats about transom-mounted transducers. The one on my previous boat would only reliably give readings below about 5 mph.

Warren
 
On our previous boat, we had a paddle wheel speed sensor and GPS - ideal for figuring the effect and speed of current. With the E-80, you can have both and it will figure set and drift for you (not that we need it much these days). I also have an aux GPS right next to the E-80 as a back up (and a comparison). I consider that "nice to know" information... especially when we were up in the PNW and dealing with some of the ripping current you guys have there.

Perhaps a bit OT regarding the initial post in this thread, but it may give some insight on transducer selection and placement.

Best wishes,
Jim B.

PS - And the water temp feature was a plus... 'cause some of you guys think it's warm when the water temp is over 55º!! The only way I'd be going in that water would be kicking and screaming with several large guys working hard to toss me overboard. (Surf water temp here today is 72º and that's way too cold for me :xseek )
 
Warren - please do tell us about your transducer - I need to figure out what system I will use when mine arrives. I like the idea of no drilling into the exterior.
 
Captains Cat":2h5jxvqa said:
Warren, did you have to move the bilge pump in that port sponson to install the transducer? Do you have a pix of it?
Click to expand...

I don't have a picture, but nothing needed to be moved as far as I know. The factory leaves a space there for people who want to use this kind of transducer. I'm going over to the boat today so I will see if I can get a picture.

Warren
 
matt_unique":3fffpu1v said:
Warren - please do tell us about your transducer - I need to figure out what system I will use when mine arrives. I like the idea of no drilling into the exterior.
Click to expand...

It's an Airmar M260 transducer and was recommended by Jeff Mesemer when he was with C-Dory. They are pretty expensive, but I got mine "free" as part of my negotiated off-season deal for the boat.

m260.jpg


Warren
 
Our Lowrance transom mounts hold the bottom all of the way up to top speeds in the high 40 knot ranges. I suspect it is the way you mount the transducer. Making sure it is in clear water, is very important.

For thru hull shooting, we make a plywood box (glassed over and to the hull) or use a PVC cylinder which is sealed to the hull. We then use a transom mount transducer, bolted to the side of the container. We then fill the container with mineral oil--We have also used thru hull transducers mounted thru the top of these boxes. This way there is no problem with mounting with silicone or epoxy--bubble trapping etc--and the transducer can be changed out easily. The AirMar does the same thing, by cutting the angle of its plastic box, to conformity of the "V" of the hull and then gluing it to the hull and filling with antifreeze.

We have also just set puck type or transom type transducers on the bottom of the hull (where it was flat), and put lead weights on it. That will work very well in the TC or CD 25 where there is likely to be some small water in the bilge, and the water will be the coupling agent for the ultra sound. The bottom of the hulls is flat in these areas, thus making it un-necessary to cut any angles or make containers. Most of these installations shoot down to the rated depth of the depth sounder--typically 600 to 1000 feet (not that there is much 1000 foot deep water near shore in Florida....
 
We have also just set puck type or transom type transducers on the bottom of the hull (where it was flat), and put lead weights on it. That will work very well in the TC or CD 25 where there is likely to be some small water in the bilge, and the water will be the coupling agent for the ultra sound. The bottom of the hulls is flat in these areas, thus making it un-necessary to cut any angles or make containers.
Click to expand...
Hi Bob et al,
I didn't realize there was a non-cored area on the CD-25 bottom other than the bilge pump sump. But yes, it's always wet there, another peeve of mine, the pump can't suck it dry. So, you have used a transom mt transducer directly on the CD-25 bottom back there? I've been unhappy with our Hummingbird transom mt transducer, mainly because of the rooster tail it kicks up, and I haven't been able to loosen the pivot bolt to adjust it, and it's too tight to ratchet. The boat's in the water all the time, so I'm working over the transom, half blind in murky Neuse water. (I think I need to make a thin walled 7/16" socket) But if I can move it to inside, that'd be great. I'm pretty sure there's no room in the sump for both the pump & a transducer.
thanks,
 
Just a few ideas about transom transducers and poor performance. most TTs are not set up right. I have had many problems my self and have had to learn how to fix them to get the performance I was expecting. picking the right spot on teh hull is the first step. If you had teh dealer install the unit them most likely you got what you paid for or more to the point what the dealer payed for, minumam wage work. Most shops that I have seen, les not included, have the techs do the engines and the shop sweepers do all the rest. its a way to work your way up to sells man or tech, but you get what you pay for most of the time. I have installed six TTs for my self and freinds over the years and placement is the key. lowering the unit just 1/4 of a inch more in to the water can make a big increase in preformance. not having your unit behind a hull strake or a rivet can also make a hugh difference. I have seen folks with the unit toward the outside edge of the hull where it is barely in the water at speed or just in rough water. Its air bubbles that destory your performance of these units. Also remember that glass can hve air in it and that will kill your performance with shoot thru transducer. Thru hulls are the best but who wants to cut a hole in their boat. so get the unit into clean water and towards the center of the boat as much as possible and you will have no problems. except the one problem I have which is the unit keeps getting stuck at 25 ft when I'm in 400ft of water. not sure why that happens.
 
Hi Thomas,
I'm not complaining about the performance, it has worked quite well. The dealer, Mobile East Marine, knows where they should be placed, and how to set them, I think. No floor sweepers setting up boats there. I just don't like it's drag, and the rooster tail it throws up. I brought that up when the boat was in for the 25hr ck on the engine, and Gene raised it a bit & tilted it to point the beam slightly fwd, which didn't help the tail. I've put another 40 hrs on the boat since then. It's down about 1/4" below the bottom, but topped out in the short slots so I can't raise it. Would like to tilt it, but the pivot bolt is too tight & I can't get a good bite on the nut with any of several sockets I have, while working at arms length down in the water. .
Cooler weather has cut into our time on the water, but it's in the water all yr 'round, ready to go. We sailed every month last yr, several times in Jan. Feb. & Mar. seem to be the worst.
 
Captains Cat":1qiov2jn said:
Warren, did you have to move the bilge pump in that port sponson to install the transducer? Do you have a pix of it?
Click to expand...

Here is a photo of the transducer. It is located aft in the starboard sponson.

Airmar.thumb.jpg

Sorry for the poor quality photo. My flash did not work (probably because the battery was low) so the photo was taken using a high ISO and I still had to tweak it to bring out the shadow detail.)

Warren
 
Al if you are only down a 1/4 of an inch and out of adjustment I would pull the boat and remount it lower. It sound like to me that it was set up wrong, and this happens a lot, and now no one want to take it off the hull and re screw it in. I would not like to either but if you want it to work right you will have to at some point. That is why its a good idea to use star board as a mounting surface on the hull. much easier to remount, upgrade, or add pucks to you hull. if you are getting a large rooster tail its wrong. as far as the pivot nut goes. its really hard to put enough pressure on the unit to get the pivot to brake loose but it will. When I say hard I mean that its hard to do in your mind because you think its going to brake. its not the pivot bolt that is tight but the catch. you really have to pull on that sucker. If it was not that way then it would move every time you go the boat on plane. what model do you have.
 
Hi Thomas,
Thanks. Yes I'm afraid of yanking too hard on it and pulling the screws out of the transom. I have done it on ones in the yard on a trailer, so know it's done but can't really get 2 hands on it down in the water. .
So, you think it should be lower than 1/4"? I'd like to try it up higher. It reads OK at all speeds now, I just think it's tilted down too much, to point the beam fwd. With the autumn leaves in the water in the creeks, it gets hung up with leaves, which throw it off. The rooster tail goes 2 ft higher than the engine at WOT, which isn't often for us.
thanks again,
 
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