Martin, Just last week I had my old knotmeter replaced with a new Speed/Log meter. I really wanted the convenience of a transom-mounted xducer, but was discouraged from it by, well, everyone, for the reasons you've cited--irregular flow, heeling, obstructions, stern-side hazards, etc. I don't like having holes in my hull, but the previous owner had come to the same conclusion about the best type and had already put a thru-hull in for the old, and I mean OLD, xducer. The previous hole was larger than the new standard diameter, so I had it done at a nearby (two hours away) boatyard, along with some other work (at this point in my neophyte experience with boats, my philosophy is that I want to do the cosmetic, interior, and accessories stuff, but I let the pros handle things structural.) The old hole was epoxied over and back into the core some, then they drilled through the epoxy to the correct size (just like they say to do for laminate protection.) He also told me that the old bedding had deteriorated so much he was surprised it hadn't leaked, but it had probably been untouched for over ten years. Speaking of plugs, that's where I got the shot ballast that is now immortalized as a picture on the MSOG site in "Flotsam and Jetsam" under "How-to". The transducer is placed just forward of the battery about 8 inches and maybe a couple of inches off the battery's right side towards the centerline. It needs to be easily accessible for switching out the transducer unit with the blanking plug for trailering. And if it's out of the water at that location, I suspect boat speed will be the least of my worries. The previous owner told me the old knotmeter transducer kept going bad, then I sent it in for repairs and it lasted a year before dying, then I found out, duh, that one MUST remove the impeller unit while running down the road, which I should have known, but only suspected. They don't register 70 mph too well. I assume it's standard on the 17s, but just in case, my battery's under the left side of the V-berth next to the v-berth bulkhead. The previous owner also had a thru-hull for the depth sounder, a separate unit, which I had a repair guy take out and epoxy in the hole. It made a perfect place to mount the new fish finder transducer that signals from inside the hull, no hole needed, and I KNOW it's solid fiberglass (and works). Because it's in an area where stuff gets shoved back and could get roughed up, I stood a 3" length of 4" diameter PVC pipe up around it. It is mounted about halfway back between the companionway and the transom, under the cockpit just to the right of the keel/bilge, maybe 6 inches off. I'll get measurements if you want. I think I've just about made myself believe that my distrust of thru-hulls is unfounded, if it's installed right and inspected every year. After all, the big boats have them as a matter of course. For what it's worth. Also, I just received some mast crutch pictures from Tod and Steve Parsons. I'll have them up in an hour. Doug At 09:13 PM 4/23/02 +0000, you wrote:
I'm planning on mounting a speed/depth sensor to my 1976 M17. I'm concerned about the effect of heeling and potential for turbulence from the cockpit drain. Any advice would be appreciated.
thanks, Martin
Duluth, MN
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------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org
Doug: Which part goes bad on the road trips. The transducer or the knotmeter? Are we talking removal of the transducer for road trips or disconnecting? My knotmeter went dead and the new one I installed to replace it was just as dead, but I didn¹t replace the old transducer....yet. That doesn¹t look like something you would want to do everyday. I use a GPS to determine speed, but that gets corrupted by current. It would be nice to know both the actual speed through the water and speed over ground. I installed my depth transducer right behind the knotmeter transducer, and maybe one strake down. I used silicone caulking...just make a little puddle and press the transducer into it. It reads fine shooting through the hull, and it¹s easy to move if you want to. Just scrape it off with a putty knife. That would not work if the transducer involved has the knotmeter wheel on it. Those are almost universally mounted off the transom...even on those 70mph bass boats. Howard
Howard, I've addressed each question below it. Let me preface by saying as a first-time real-boat servant (I would debate what owns who) and a never-time-working knotmeter owner, I've decided to start this boaty-sitting odyssey by erring on the side of caution. Or to put it succinctly, "written directions are the first refuge of the ignorant". Then at some belated point I reach analysis paralysis, throw up my hands, and like-y Nike, "just do it". At 06:11 PM 4/24/02 -0500, you wrote:
Doug:
Which part goes bad on the road trips. The transducer or the knotmeter?
As I recall from August 2000 when the unit went in for service, the meter went bad. I don't have the receipt, but just tonight I looked at the parts and the meter guts housing looks new and the impeller (paddlewheel transducer) looks used. I recall the technician saying that a competent person can stick multi-meter probes into the correct connector leads from the transducer, spin it and determine which unit is bad based on amount of electrical output. So I just sent it in. You may be able to call the manufacturer's service department and get the particulars, it's not my area. Might be a first step, though.
Are we talking removal of the transducer for road trips or disconnecting?
I'm just going by what the manual says from here on out (my model is Standard Horizon SL45): "To protect the paddlewheel insert, use the long blanking plug when the boat will be moored in salt water for more than a week, the boat will be removed from the water, or aquatic growth build-up on the paddlewheel is suspected due to inaccurate readings from the instrument." Under "Servicing the Paddlewheel Insert": The water lubricated paddlewheel bearings have a life of 5 years on low speed boats (less than 10 kn) and 1 year on high speed vessels". I take that to mean that more spinning, especially out of water, means more wear. The big question I have is, does the paddlewheel spin while running down the road? As easily as it spins when I just blow on it, I think it must (I know I'm a blowhard, but not THAT hard). When I asked the boatyard guy, he said to take it out when trailering. The model I have is simple to remove and replace the paddlewheel plug with the blanking plug, which will protect both the paddlewheel and the meter unit. Takes about 5 seconds, since I replaced one of the retaining rings to the locking pin with a hitch pin. Pull the hitch pin, pull the retaining pin, slide the impeller unit out of the thru-hull sleeve, and reverse the process with the blanking plug. Considering how easy it is to do, why take the chance?
My knotmeter went dead and the new one I installed to replace it was just as dead, but I didn t replace the old transducer....yet. That doesn t look like something you would want to do everyday.
I don't think it's that difficult on my unit. I can order just a paddlewheel kit. On mine, the thru-hull is a separate sleeve that is permanently installed. The transducer unit slides in and out of it, sealed with a few lubricated O-rings and locked into place with the retaining pin. The thru-hull sleeve doesn't have to be removed.
I use a GPS to determine speed, but that gets corrupted by current. It would be nice to know both the actual speed through the water and speed over ground.
My feelings exactly, with the exception of knowing Velocity Made Good, because that requires the additional wind speed instrumentation (WS45), which I'm not planning on springing for anytime soon, since WM sells it for $650. In the Series 45 system, it integrates through the NMEA-0183 interface. I'm pretty sure all of the systems must require the same instrumentation for VMG. More importantly for me, is my need to learn how to trim sails, point optimally, dead-reckon, etc., and I want instant feedback on my adjustments. Plus I like multi-day cruises, sometimes out of sight of land, and want two different methods to estimate and double-check position.
I installed my depth transducer right behind the knotmeter transducer, and maybe one strake down. I used silicone caulking...just make a little puddle and press the transducer into it. It reads fine shooting through the hull, and it s easy to move if you want to. Just scrape it off with a putty knife.
Don't know about that. but since it works, it sounds like a great solution.
That would not work if the transducer involved has the knotmeter wheel on it. Those are almost universally mounted off the transom...even on those 70mph bass boats.
For some reason, that wasn't the impression I ended up with (transom-mounted on sailboats), but that is just my impression. I think exactly because they are fast powerboats, usually planing powerboats, they must mount well aft. Quoting the installation book again, under "Mounting Location": "Turbulence-free water must flow over the paddlewheel at all speeds. Choose an accessible spot with a minimum deadrise angle." Then, for different types of boats: "Displacement hull powerboats--Locate the sensor amidships near the centerline. Planing hull powerboats--Mount the sensor well aft to insure that it is in contact with the water at high speeds. Fin keel sailboats--Mount the sensor on or as close as possible to the centerline and forward of the fin keel 30-60cm (1-2'). Full keel sailboats--Locate the sensor amidships and away from the keel but still in the when the boat is heeled." This little blurb is from the meter book, not the sensor book, unlike the rest of this stuff. Under "Impeller Installation": "Sailboats On sailboats, the impeller should be mounted close to the centerline of the hull and ahead of the keel by 12-24 inches (300-600 mm) so that the flow disturbance caused by the keel does not affect the flow of water past the paddle wheel". Finally, this: "Caution: Do not mount the sensor in a turbulent area; near water intake or discharge openings; behind strakes, fittings or hull irregularities; near the keel or behind eroding paint (an indication of turbulence)." I think it was the "behind strakes" part that made up my mind and may make the M-boats an exception to the general rule. Whether I would have put it in its current position had there not already been a thru-hull there, I don't know. But my transom has the outboard on the port side, the rudder amidships, and a waterline step on the starboard side, where a rope swim ladder goes when anchored. I couldn't really find a place that I thought would be out of harm's way, and out of turbulence. Granted, all of this may be for the benefit of racers, and not that important for the way I sail, but once again I adhere to my little motto at the top. If you like, I can copy the sensor installation book and send it to you. It's four pages. I'd like to know how the transom mount works, if you go that way. It's never too late for me to buy MORE boat stuff and REDO something else AGAIN. ;) Hope this helps Howard, Doug ------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org
Turns out I have an Standard Horizon AS45, and it has the same plug and sleeve arrangement you describe. So now I can swap the plug out without pulling and bedding the sleeve. That¹s the part that I was dreading. But if it¹s the unit itself that gets cooked and not the speed sensor in the water, you could just disconnect it at the unit.......and save swapping the plug for serious road trips....like CBR¹s, and such. I have all the instructions for both this unit and the depthfinder half of my Garmin GPS/depthfinder and they are just as you described them. The unit¹s I was talking about are more like Eagle/Lowrance/Hummingbird type depthsounders, with speed sensor. The transducer and speed sensor are all one unit. They are not through hulls. These are almost impossible to mount anywhere but on the transom. But I learned something new today, and can now go to bed! Howard
Doug, do I read your message right that you mount your depth transducer on a bed of caulking to the hull? I thought they had to be immersed in water or some other liquid, sealed inside a short section of pvc pipe,or other such container. Do they work simply sealed to the inside of the boat ? Wayne M17 #204 Intrepid
----- Original Message ----- From: Doug King To: montgomery_boats@mailman.xmission.com Sent: Wednesday, April 24, 2002 9:41 PM Subject: Re: M_Boats: transducer position
Howard, I've addressed each question below it. Let me preface by saying as a first-time real-boat servant (I would debate what owns who) and a never-time-working knotmeter owner, I've decided to start this boaty-sitting odyssey by erring on the side of caution. Or to put it succinctly, "written directions are the first refuge of the ignorant". Then at some belated point I reach analysis paralysis, throw up my hands, and like-y Nike, "just do it". At 06:11 PM 4/24/02 -0500, you wrote: Doug: Which part goes bad on the road trips. The transducer or the knotmeter? As I recall from August 2000 when the unit went in for service, the meter went bad. I don't have the receipt, but just tonight I looked at the parts and the meter guts housing looks new and the impeller (paddlewheel transducer) looks used. I recall the technician saying that a competent person can stick multi-meter probes into the correct connector leads from the transducer, spin it and determine which unit is bad based on amount of electrical output. So I just sent it in. You may be able to call the manufacturer's service department and get the particulars, it's not my area. Might be a first step, though. Are we talking removal of the transducer for road trips or disconnecting? I'm just going by what the manual says from here on out (my model is Standard Horizon SL45): "To protect the paddlewheel insert, use the long blanking plug when the boat will be moored in salt water for more than a week, the boat will be removed from the water, or aquatic growth build-up on the paddlewheel is suspected due to inaccurate readings from the instrument." Under "Servicing the Paddlewheel Insert": The water lubricated paddlewheel bearings have a life of 5 years on low speed boats (less than 10 kn) and 1 year on high speed vessels". I take that to mean that more spinning, especially out of water, means more wear. The big question I have is, does the paddlewheel spin while running down the road? As easily as it spins when I just blow on it, I think it must (I know I'm a blowhard, but not THAT hard). When I asked the boatyard guy, he said to take it out when trailering. The model I have is simple to remove and replace the paddlewheel plug with the blanking plug, which will protect both the paddlewheel and the meter unit. Takes about 5 seconds, since I replaced one of the retaining rings to the locking pin with a hitch pin. Pull the hitch pin, pull the retaining pin, slide the impeller unit out of the thru-hull sleeve, and reverse the process with the blanking plug. Considering how easy it is to do, why take the chance? My knotmeter went dead and the new one I installed to replace it was just as dead, but I didn t replace the old transducer....yet. That doesn t look like something you would want to do everyday. I don't think it's that difficult on my unit. I can order just a paddlewheel kit. On mine, the thru-hull is a separate sleeve that is permanently installed. The transducer unit slides in and out of it, sealed with a few lubricated O-rings and locked into place with the retaining pin. The thru-hull sleeve doesn't have to be removed. I use a GPS to determine speed, but that gets corrupted by current. It would be nice to know both the actual speed through the water and speed over ground. My feelings exactly, with the exception of knowing Velocity Made Good, because that requires the additional wind speed instrumentation (WS45), which I'm not planning on springing for anytime soon, since WM sells it for $650. In the Series 45 system, it integrates through the NMEA-0183 interface. I'm pretty sure all of the systems must require the same instrumentation for VMG. More importantly for me, is my need to learn how to trim sails, point optimally, dead-reckon, etc., and I want instant feedback on my adjustments. Plus I like multi-day cruises, sometimes out of sight of land, and want two different methods to estimate and double-check position. I installed my depth transducer right behind the knotmeter transducer, and maybe one strake down. I used silicone caulking...just make a little puddle and press the transducer into it. It reads fine shooting through the hull, and it s easy to move if you want to. Just scrape it off with a putty knife. Don't know about that. but since it works, it sounds like a great solution. That would not work if the transducer involved has the knotmeter wheel on it. Those are almost universally mounted off the transom...even on those 70mph bass boats. For some reason, that wasn't the impression I ended up with (transom-mounted on sailboats), but that is just my impression. I think exactly because they are fast powerboats, usually planing powerboats, they must mount well aft. Quoting the installation book again, under "Mounting Location": "Turbulence-free water must flow over the paddlewheel at all speeds. Choose an accessible spot with a minimum deadrise angle." Then, for different types of boats: "Displacement hull powerboats--Locate the sensor amidships near the centerline. Planing hull powerboats--Mount the sensor well aft to insure that it is in contact with the water at high speeds. Fin keel sailboats--Mount the sensor on or as close as possible to the centerline and forward of the fin keel 30-60cm (1-2'). Full keel sailboats--Locate the sensor amidships and away from the keel but still in the when the boat is heeled." This little blurb is from the meter book, not the sensor book, unlike the rest of this stuff. Under "Impeller Installation": "Sailboats On sailboats, the impeller should be mounted close to the centerline of the hull and ahead of the keel by 12-24 inches (300-600 mm) so that the flow disturbance caused by the keel does not affect the flow of water past the paddle wheel". Finally, this: "Caution: Do not mount the sensor in a turbulent area; near water intake or discharge openings; behind strakes, fittings or hull irregularities; near the keel or behind eroding paint (an indication of turbulence)." I think it was the "behind strakes" part that made up my mind and may make the M-boats an exception to the general rule. Whether I would have put it in its current position had there not already been a thru-hull there, I don't know. But my transom has the outboard on the port side, the rudder amidships, and a waterline step on the starboard side, where a rope swim ladder goes when anchored. I couldn't really find a place that I thought would be out of harm's way, and out of turbulence. Granted, all of this may be for the benefit of racers, and not that important for the way I sail, but once again I adhere to my little motto at the top. If you like, I can copy the sensor installation book and send it to you. It's four pages. I'd like to know how the transom mount works, if you go that way. It's never too late for me to buy MORE boat stuff and REDO something else AGAIN. ;) Hope this helps Howard, Doug ------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org
Wayne, I mounted a through-hull transducer in my M15 on the inside of the hull just forward of the keel/centerboard. I used clear silicone instead of the epoxy supplied with the transducer, just in case I needed to move the unit to a different position later. Use a big glob of silicone and make sure there are no bubbles it. Gently weight the transducer until the silicone sets. My Eagle Magna depth sounder/fish finder works great with this installation... and I didn't have to drill another hole in the boat. Joe Kidd M15 #207 "Poco a Poco" ----- Original Message ----- From: wayne yeargain To: montgomery_boats@mailman.xmission.com Sent: Friday, April 26, 2002 8:48 PM Subject: Re: M_Boats: transducer position Doug, do I read your message right that you mount your depth transducer on a bed of caulking to the hull? I thought they had to be immersed in water or some other liquid, sealed inside a short section of pvc pipe,or other such container. Do they work simply sealed to the inside of the boat ? Wayne M17 #204 Intrepid
----- Original Message ----- From: Doug King To: montgomery_boats@mailman.xmission.com Sent: Wednesday, April 24, 2002 9:41 PM Subject: Re: M_Boats: transducer position
Howard, I've addressed each question below it. Let me preface by saying as a first-time real-boat servant (I would debate what owns who) and a never-time-working knotmeter owner, I've decided to start this boaty-sitting odyssey by erring on the side of caution. Or to put it succinctly, "written directions are the first refuge of the ignorant". Then at some belated point I reach analysis paralysis, throw up my hands, and like-y Nike, "just do it". At 06:11 PM 4/24/02 -0500, you wrote: Doug: Which part goes bad on the road trips. The transducer or the knotmeter? As I recall from August 2000 when the unit went in for service, the meter went bad. I don't have the receipt, but just tonight I looked at the parts and the meter guts housing looks new and the impeller (paddlewheel transducer) looks used. I recall the technician saying that a competent person can stick multi-meter probes into the correct connector leads from the transducer, spin it and determine which unit is bad based on amount of electrical output. So I just sent it in. You may be able to call the manufacturer's service department and get the particulars, it's not my area. Might be a first step, though. Are we talking removal of the transducer for road trips or disconnecting? I'm just going by what the manual says from here on out (my model is Standard Horizon SL45): "To protect the paddlewheel insert, use the long blanking plug when the boat will be moored in salt water for more than a week, the boat will be removed from the water, or aquatic growth build-up on the paddlewheel is suspected due to inaccurate readings from the instrument." Under "Servicing the Paddlewheel Insert": The water lubricated paddlewheel bearings have a life of 5 years on low speed boats (less than 10 kn) and 1 year on high speed vessels". I take that to mean that more spinning, especially out of water, means more wear. The big question I have is, does the paddlewheel spin while running down the road? As easily as it spins when I just blow on it, I think it must (I know I'm a blowhard, but not THAT hard). When I asked the boatyard guy, he said to take it out when trailering. The model I have is simple to remove and replace the paddlewheel plug with the blanking plug, which will protect both the paddlewheel and the meter unit. Takes about 5 seconds, since I replaced one of the retaining rings to the locking pin with a hitch pin. Pull the hitch pin, pull the retaining pin, slide the impeller unit out of the thru-hull sleeve, and reverse the process with the blanking plug. Considering how easy it is to do, why take the chance? My knotmeter went dead and the new one I installed to replace it was just as dead, but I didn t replace the old transducer....yet. That doesn t look like something you would want to do everyday. I don't think it's that difficult on my unit. I can order just a paddlewheel kit. On mine, the thru-hull is a separate sleeve that is permanently installed. The transducer unit slides in and out of it, sealed with a few lubricated O-rings and locked into place with the retaining pin. The thru-hull sleeve doesn't have to be removed. I use a GPS to determine speed, but that gets corrupted by current. It would be nice to know both the actual speed through the water and speed over ground. My feelings exactly, with the exception of knowing Velocity Made Good, because that requires the additional wind speed instrumentation (WS45), which I'm not planning on springing for anytime soon, since WM sells it for $650. In the Series 45 system, it integrates through the NMEA-0183 interface. I'm pretty sure all of the systems must require the same instrumentation for VMG. More importantly for me, is my need to learn how to trim sails, point optimally, dead-reckon, etc., and I want instant feedback on my adjustments. Plus I like multi-day cruises, sometimes out of sight of land, and want two different methods to estimate and double-check position. I installed my depth transducer right behind the knotmeter transducer, and maybe one strake down. I used silicone caulking...just make a little puddle and press the transducer into it. It reads fine shooting through the hull, and it s easy to move if you want to. Just scrape it off with a putty knife. Don't know about that. but since it works, it sounds like a great solution. That would not work if the transducer involved has the knotmeter wheel on it. Those are almost universally mounted off the transom...even on those 70mph bass boats. For some reason, that wasn't the impression I ended up with (transom-mounted on sailboats), but that is just my impression. I think exactly because they are fast powerboats, usually planing powerboats, they must mount well aft. Quoting the installation book again, under "Mounting Location": "Turbulence-free water must flow over the paddlewheel at all speeds. Choose an accessible spot with a minimum deadrise angle." Then, for different types of boats: "Displacement hull powerboats--Locate the sensor amidships near the centerline. Planing hull powerboats--Mount the sensor well aft to insure that it is in contact with the water at high speeds. Fin keel sailboats--Mount the sensor on or as close as possible to the centerline and forward of the fin keel 30-60cm (1-2'). Full keel sailboats--Locate the sensor amidships and away from the keel but still in the when the boat is heeled." This little blurb is from the meter book, not the sensor book, unlike the rest of this stuff. Under "Impeller Installation": "Sailboats On sailboats, the impeller should be mounted close to the centerline of the hull and ahead of the keel by 12-24 inches (300-600 mm) so that the flow disturbance caused by the keel does not affect the flow of water past the paddle wheel". Finally, this: "Caution: Do not mount the sensor in a turbulent area; near water intake or discharge openings; behind strakes, fittings or hull irregularities; near the keel or behind eroding paint (an indication of turbulence)." I think it was the "behind strakes" part that made up my mind and may make the M-boats an exception to the general rule. Whether I would have put it in its current position had there not already been a thru-hull there, I don't know. But my transom has the outboard on the port side, the rudder amidships, and a waterline step on the starboard side, where a rope swim ladder goes when anchored. I couldn't really find a place that I thought would be out of harm's way, and out of turbulence. Granted, all of this may be for the benefit of racers, and not that important for the way I sail, but once again I adhere to my little motto at the top. If you like, I can copy the sensor installation book and send it to you. It's four pages. I'd like to know how the transom mount works, if you go that way. It's never too late for me to buy MORE boat stuff and REDO something else AGAIN. ;) Hope this helps Howard, Doug ------------------------------------------ Doug King M-17 #404 "Vixen" Montgomery Sailboats Owners Group Web site: http://msog.org Email: mailto:msog@msog.org
Wayne, Two votes for silicone, two for epoxy. Might it depend on the manufacturer? I have a Humminbird. If you can wait a second, I'll fetch my unerring instructions... Let's see, I think they're on this shelf...hmm..."Kama Sutra for Dummies"..."Autobiography of Red Skelton for Dummies" by Clem Cadiddlehopper..."DIY Nuclear Power for Dummies" by Homer Simpson...Ah, here it is, "Fishfinder Transducers for Dummies". Yup, says to use epoxy goo, and I don't know enough to risk angering the goo gods. I had the impression that you needed a dense, solid goo to shoot through, but seems to me if silicone goo gives accurate readings, what a great solution. Just my opinion. Installation info for Humminbird is at http://www.humminbird.com/hb_MoreSupport.asp?id=26 Correct me if I'm wrong on any of this, but I also think some confusion has been created by manufacturers in the use of the term "thru-hull", which used to mean you gotta drill a hole through the hull. With the newer transducers, thru-hull means it senses from inside the hull, through the hull, with no hullholes needed (I used to live in a hullhole. Be a good name for a waterfront bar). I think all of the popular fishfinders use the inside-the-hull transducers that can optionally be hung off the transom with a mounting bracket, but it'd probably be wise to make sure of what type of thru-hull they mean. Maybe someone can confirm if it's worth putting it as far forward on the hull as possible while still in an area that stays in contact with the water, since they are forward-looking and doing so would give a few more yards' notice of, to put it gently, an unexpectedly abrupt cessation of forward motion. On the other hand, these are short, shallow-draft boats; maybe it doesn't really matter. ---- Sorry, I can't help it: ;) Now that I think about it, the silicone idea sounded good at first, seein's how it works perfectly and all. But I gotta say, I think it shows a certain lack of commitment. I mean, how long could it take to reposition it? A couple of minutes? A nickel razor blade, a little scraping, a tiny scratch or two? Bah. Humbug (or Humminbird). That's not a REAL boat job. I think it's important to believe completely in one's own poor judgement, ignoring once again the lessons learned last time, and just slap 'er down in the wrong place to stay. It'll take me a good 5 or 6 hours and a couple hundred bucks to change its location if it doesn't read accurately, not to mention the cost associated with how I'll find out it doesn't read accurately. Apparently, THAT'S what boat ownership's all about. As a newbie, I've learned BOAT stands for "Break Out Another Thousand". Fortunately, mine works great. ---- ;) This Month's Useless M-Fact: If you are lucky enough not to have seen the steel shot used for ballast in the 15s and 17s (at least that's what the boatyard said it was), there is a picture of some of the little buggers on the MSOG site at http://msog.org/how-to/how-to_flotjet.cfm (second ditty). I had no idea of their size, but seeing them naturally aroused my need to know: How many more of these will I be seeing someday, and how can I put them to good use? I mean they're just slowing down the boat where they are now. So I took some to work Friday to be weighed on a balance in one of the labs where a fellow (actually fella) sailor works and we found that the weight of 10 of them averaged .104 grams each (it was a slow day for both of us). Using a nice round number of 454.00889 grams per pound and ignoring significant figures, there are 4365.47 of them to a pound, which means an M-15 keel of 275 pounds contains 1,200,504, and an M-17's keel of 580 pounds has about 2,531,972 of the little guys snuggled up in there. I read that lead is used in the M-23, and I found no mention if it's in the form of shot or not. Feel free to check my arithmetic, I ran out of fingers and toes pretty early in the count, after 24. Now Bob Eeg and all M-owners can brag that each boat contains well over a million, or two and a half million, separate components fitted together perfectly, even though most of mine are probably slowly rust-welding themselves together. Plus, I've figured out a way to do get rid of them AND not have to learn how to do reverse-routing on the GPS. I'm gonna drill a small hole in the keel and let them dribble out one at a time. Then I'll epoxy an 11" diameter DetectorPro Headhunter Pulse underwater metal detector with self-draining anodized aluminum rod of durable baked-on powder coating and permanently encapsulated high-output piezoelectric headphone transducers ($699 at http://www.detectorpro.com/headhunterpulse.htm) to my hull and just squeal my way back. I gotta lay off Car Talk. Doug the Circus Freak At 11:21 PM 4/26/02 -0700, you wrote:
Wayne,
I mounted a through-hull transducer in my M15 on the inside of the hull just forward of the keel/centerboard. I used clear silicone instead of the epoxy supplied with the transducer, just in case I needed to move the unit to a different position later. Use a big glob of silicone and make sure there are no bubbles it. Gently weight the transducer until the silicone sets. My Eagle Magna depth sounder/fish finder works great with this installation... and I didn't have to drill another hole in the boat.
Joe Kidd M15 #207 "Poco a Poco"
----- Original Message ----- From: <mailto:wayne@ev1.net>wayne yeargain To: <mailto:montgomery_boats@mailman.xmission.com>montgomery_boats@mailman.xm ission.com Sent: Friday, April 26, 2002 8:48 PM Subject: Re: M_Boats: transducer position
Doug, do I read your message right that you mount your depth transducer on a bed of caulking to the hull? I thought they had to be immersed in water or some other liquid, sealed inside a short section of pvc pipe,or other such container. Do they work simply sealed to the inside of the boat ?
Wayne M17 #204 Intrepid
The May 2002 issue of SAIL has a one page "how-to" on "Mounting an In-Hull Depthsounder". Look on page 103. They suggest epoxying a piece of PVC to the hull, floating the transducer in mineral oil and capping the pipe with a reducer coupling to hold everything together. Don Haas M15-248 wayne yeargain wrote:
Doug, do I read your message right that you mount your depth transducer on a bed of caulking to the hull?I thought they had to be immersed in water or some other liquid, sealed inside a short section of pvcpipe,or other such container.Do they work simply sealed to the inside of the boat ? Wayne M17 #204 Intrepid >-
participants (6)
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Don Haas -
Doug King -
Howard Audsley -
Joe Kidd -
Lexi Gulbranson -
wayne yeargain