I am having difficulty with my ST60 speed indicator reading. Someone told me to remove the plug connected to the transducer and make sure the impeller was indeed revolving. I have not done this before and was hoping someone could give me a little direction.
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Good to have the dummy plug standing by.
Ken: It is a good idea to have the dummy plug standing by. If you are nervous about preforming this manuver, ask one of your dockmates. I have not found a single time when one of them was not anixous to sink my boat. If you don't have a dummy plug, you can just put a towel over the thru hull and have someone clean the impeller for you. Take notice how it was extracted. I believe that it is indexed so there is only one way to put it back.
Ken: It is a good idea to have the dummy plug standing by. If you are nervous about preforming this manuver, ask one of your dockmates. I have not found a single time when one of them was not anixous to sink my boat. If you don't have a dummy plug, you can just put a towel over the thru hull and have someone clean the impeller for you. Take notice how it was extracted. I believe that it is indexed so there is only one way to put it back.
Hi Ken, I've pulled ours before and as Steve...
said have the plug ready to go when you pull the transducer out. Our transducer has an arrow molded into the top to help you aline the impeller when it goes back in after cleaning. Also, slather some teflon grease on the 'O' rings to help it slide back in and seat properly. If you have a square five gallon plastic bucket with the bottom removed, use it around the transducer to keep water from splashing all over things when you remove and replace. Having another pair of hands always helps. Terry
said have the plug ready to go when you pull the transducer out. Our transducer has an arrow molded into the top to help you aline the impeller when it goes back in after cleaning. Also, slather some teflon grease on the 'O' rings to help it slide back in and seat properly. If you have a square five gallon plastic bucket with the bottom removed, use it around the transducer to keep water from splashing all over things when you remove and replace. Having another pair of hands always helps. Terry
The First Time is the Worst
I can still remember the first time that I did this job. It goes against all of the basic boating instincts to deliberately create a hole in the bottom of the boat and watch the resultant fountain of water pour in. It occurred to me that it would not be that difficult to create a pad of just about any pliable material in the middle of a piece of light line and run it under the hull to straddle the impeller location. This temporary patch would still leak a bit, but should kill the frightening gusher and thus steady the nerves. Anyone tried this?
I can still remember the first time that I did this job. It goes against all of the basic boating instincts to deliberately create a hole in the bottom of the boat and watch the resultant fountain of water pour in. It occurred to me that it would not be that difficult to create a pad of just about any pliable material in the middle of a piece of light line and run it under the hull to straddle the impeller location. This temporary patch would still leak a bit, but should kill the frightening gusher and thus steady the nerves. Anyone tried this?
or if the water temp is
warm, go for a swim and check it in place. If the boat has not been used in a while some growth may have clogged it and it will just need to be spun by hand a few times to break loose or try going for a sail it will usually start spinning after a while unless the unit is bad. If you just put your boat back in could some bottom paint possible have clogged it, stopping it from spinning ?? If so same procedure applies.
warm, go for a swim and check it in place. If the boat has not been used in a while some growth may have clogged it and it will just need to be spun by hand a few times to break loose or try going for a sail it will usually start spinning after a while unless the unit is bad. If you just put your boat back in could some bottom paint possible have clogged it, stopping it from spinning ?? If so same procedure applies.
Do not try this alone!
My biggest fear is that something will go wrong while it's out and I won't be able to get the plug or the transducer back in the hole. I'd be stuck there with my "finger in the dike" so to speak, yelling at the top of my lungs trying to get somebody outside's attention. I get a dock neighbor to stand by if my wife is not there. It's a simple job. Just have everything you need within reach and move quickly. If your transducer is located in a relatively accessable spot, you should be able to swap it out and back in with less than 2 qts of seawater getting in. Newer transducers have a spring-loaded baffle in the tube that greatly reduces the amount of water that comes in.
My biggest fear is that something will go wrong while it's out and I won't be able to get the plug or the transducer back in the hole. I'd be stuck there with my "finger in the dike" so to speak, yelling at the top of my lungs trying to get somebody outside's attention. I get a dock neighbor to stand by if my wife is not there. It's a simple job. Just have everything you need within reach and move quickly. If your transducer is located in a relatively accessable spot, you should be able to swap it out and back in with less than 2 qts of seawater getting in. Newer transducers have a spring-loaded baffle in the tube that greatly reduces the amount of water that comes in.
Easy
I have removed it at the dock many times and first time doing so may scare you but if you have the spare plug handy, check to see the arrow on top before pulling it out and be careful not to pull on cable and just line up the arrow putting back in. I have also pulled the transducer when under way or sailing,some times I would remove it when leaving the boat for a week so it would stay cleaner that way and than forget to install it before heading out and just reinstall it while out sailing,it just may need to be cleaned and has some build up on it. nick
I have removed it at the dock many times and first time doing so may scare you but if you have the spare plug handy, check to see the arrow on top before pulling it out and be careful not to pull on cable and just line up the arrow putting back in. I have also pulled the transducer when under way or sailing,some times I would remove it when leaving the boat for a week so it would stay cleaner that way and than forget to install it before heading out and just reinstall it while out sailing,it just may need to be cleaned and has some build up on it. nick
I have a 310 and this was and is a problem... Not so much as the removal it self but the number of times it has to be done a season due to fouling around the impeller... It has to be consistently removed and cleaned... I stopped using it in favor of the speed reading on my GPS... Suggest you only do removal at the dock... I used to remove it after a weekend of sailing... or when the boat would be out of use for a week of so to eliminate the fouling problem...
Fouled impeller
I have a new Hunter 38. It has been in the water since January. The knotmeter hasn't worked since February. I suspected a fouled impeller but didn't get around to pulling the unit out of its through hull fitting until yesterday. Yep -- completely fouled with slime and small barnacles and frozen. It is easy to remove. Loosen the ring that holds it in place. Put it out and put the blank plug in fast. You will get about 1/2 gallon of water into the boat, but it shouldn't gush everywhere. Use an ice pick or small diameter punch to push the spindle out of the jaws that hold the small impeller or wheel. That frees the wheel. Use a putty knife to scrape the gunk off the wheel. Use some wet-dry sandpaper to remove the last of the barnacles. When it is clean and dry, spray it with the type of anti fouling paint used on outdrives. Clean the spindle and jaws. Spray the jaws. Let the paint dry. Reassemble and shove it back into the through hull hole and tighten the locking ring. It will last for about a year(or more) without fouling, at least it does in Galveston bay.
I have a new Hunter 38. It has been in the water since January. The knotmeter hasn't worked since February. I suspected a fouled impeller but didn't get around to pulling the unit out of its through hull fitting until yesterday. Yep -- completely fouled with slime and small barnacles and frozen. It is easy to remove. Loosen the ring that holds it in place. Put it out and put the blank plug in fast. You will get about 1/2 gallon of water into the boat, but it shouldn't gush everywhere. Use an ice pick or small diameter punch to push the spindle out of the jaws that hold the small impeller or wheel. That frees the wheel. Use a putty knife to scrape the gunk off the wheel. Use some wet-dry sandpaper to remove the last of the barnacles. When it is clean and dry, spray it with the type of anti fouling paint used on outdrives. Clean the spindle and jaws. Spray the jaws. Let the paint dry. Reassemble and shove it back into the through hull hole and tighten the locking ring. It will last for about a year(or more) without fouling, at least it does in Galveston bay.
Self sealing thru hull
I replaced the knot log on my boat with a self sealing thru hull. I remove the log every time I leave the boat that way it never needs paint and always stays clean. It takes all of ten seconds and the self sealing thru hull prevents most of the water from coming in while I install the plug. Whatever gets in is easily cleaned up with a rag.
I replaced the knot log on my boat with a self sealing thru hull. I remove the log every time I leave the boat that way it never needs paint and always stays clean. It takes all of ten seconds and the self sealing thru hull prevents most of the water from coming in while I install the plug. Whatever gets in is easily cleaned up with a rag.
Thanks Guys, I really appreciate the great comments I have received. I'll let everyone know how it goes after next weekend.
two things to add
Like nearly everyone who responded, I have had to clean a fouled speed impeller. I have pulled it and replaced it while the boat was in the water several times. Two additional observations: 1. Apply a liberal amount of Desinex (sp?) to it (the ointment used for diaper rash) while it is out of the water. It tends to retard the accumulation of critters and plants. I sail on lake Ontario and it often lasts the entire season for me. Prior to the Desinex, Zebra Mussle encrustations happened about twice per year. Your mileage may vary depending on use and local. 2. My impeller plug once loosened while in use. Apparently, water current can cause enough twisting force to back out the threaded cap, especially if you use spray silicone or grease to keep it lubed. Mine loosened just enough to allow a small leak into the boat that I noticed by realizing the bilge pump kept cycling on. My transducer has small eyes on it to attach a keeper wire (as per the Raymarine instructions). Be sure to do that. I simply attach a shortwire to each eye and then twist them together once the plug is in place.
Like nearly everyone who responded, I have had to clean a fouled speed impeller. I have pulled it and replaced it while the boat was in the water several times. Two additional observations: 1. Apply a liberal amount of Desinex (sp?) to it (the ointment used for diaper rash) while it is out of the water. It tends to retard the accumulation of critters and plants. I sail on lake Ontario and it often lasts the entire season for me. Prior to the Desinex, Zebra Mussle encrustations happened about twice per year. Your mileage may vary depending on use and local. 2. My impeller plug once loosened while in use. Apparently, water current can cause enough twisting force to back out the threaded cap, especially if you use spray silicone or grease to keep it lubed. Mine loosened just enough to allow a small leak into the boat that I noticed by realizing the bilge pump kept cycling on. My transducer has small eyes on it to attach a keeper wire (as per the Raymarine instructions). Be sure to do that. I simply attach a shortwire to each eye and then twist them together once the plug is in place.
pimerese
If your instruments are Raymarine the knot log should have a notch on it to locate it in the forward facing position. This notch will not permit the log to turn in any direction. The screw cap then holds it down in place. Your cap may not have been tight but it could not have been caused by a rotating log.
If your instruments are Raymarine the knot log should have a notch on it to locate it in the forward facing position. This notch will not permit the log to turn in any direction. The screw cap then holds it down in place. Your cap may not have been tight but it could not have been caused by a rotating log.
Alan, after thinking about it, what you say makes sense... but
somehow, possibly from vibration alone, the cap loosened over the course of a sailing season. I cant reliably explain how it did this (in hindsight, my original explaination may seem improbable as I stated it), but I can assure you it was tight at installation and worked its way loose all on its own, in less than one summer. Consider this: Mine is one of the thru hulls with the integrated self closing valve designed to minimize water flow when the sensor is removed. Also, the "notch" you speak of is actually a V shape that allows about 1/4" of radial play when the sensor is seated. Because its a V shape, as torque is applied to the sensor body, my assumption is that there would be an upward force on the sensor as its "key" rides up the side of the V notch. This force might well extent to the threaded cap. As the torque direction changes, the force on the sensor and/or cap would also change or at least be relaxed. I felt that with enough repetition of this process, the cap could loosen enough to eventually break a seal and cause a leak. Perhaps the mechanics of that explaination are incorrect. I dont need to debate it. I just know it can happen, because it happened to me. In any event, the Airmar folks (the manufacturer of the transducers Raymar supplies with their instruments, or at least, with my Bidata kit) must have forseen this problem as well. They include a wire safety wrap in the installation kit specifically for this purpose and explain its installation in the Airmar users manual. I stand by the reccommendation to use it.
somehow, possibly from vibration alone, the cap loosened over the course of a sailing season. I cant reliably explain how it did this (in hindsight, my original explaination may seem improbable as I stated it), but I can assure you it was tight at installation and worked its way loose all on its own, in less than one summer. Consider this: Mine is one of the thru hulls with the integrated self closing valve designed to minimize water flow when the sensor is removed. Also, the "notch" you speak of is actually a V shape that allows about 1/4" of radial play when the sensor is seated. Because its a V shape, as torque is applied to the sensor body, my assumption is that there would be an upward force on the sensor as its "key" rides up the side of the V notch. This force might well extent to the threaded cap. As the torque direction changes, the force on the sensor and/or cap would also change or at least be relaxed. I felt that with enough repetition of this process, the cap could loosen enough to eventually break a seal and cause a leak. Perhaps the mechanics of that explaination are incorrect. I dont need to debate it. I just know it can happen, because it happened to me. In any event, the Airmar folks (the manufacturer of the transducers Raymar supplies with their instruments, or at least, with my Bidata kit) must have forseen this problem as well. They include a wire safety wrap in the installation kit specifically for this purpose and explain its installation in the Airmar users manual. I stand by the reccommendation to use it.
pimerese
Just for giggles I went back to check mine. It is an Airmar Model ST600 and indeed the notch is a square shouldered notch with zero play in the thru hull. Maybe mine is an earlier version. From the owners manual: MAINTAINING THE SENSOR Blanking Plug To protect the paddlewheel, a blanking plug is provided and should be used when the boat is kept in salt water for more than a week, or removed from the water with slings or fork lift. Without question if the retaining cap is coming loose it is a good idea to secure it with wire ties. Since I pull mine every time I use the boat and have never found the retaining cap to come loose I don't find this to be an issue.
Just for giggles I went back to check mine. It is an Airmar Model ST600 and indeed the notch is a square shouldered notch with zero play in the thru hull. Maybe mine is an earlier version. From the owners manual: MAINTAINING THE SENSOR Blanking Plug To protect the paddlewheel, a blanking plug is provided and should be used when the boat is kept in salt water for more than a week, or removed from the water with slings or fork lift. Without question if the retaining cap is coming loose it is a good idea to secure it with wire ties. Since I pull mine every time I use the boat and have never found the retaining cap to come loose I don't find this to be an issue.
Yep, there is certainly a difference
Mine is an Airmar 300 series. Its about 4 years old. It also carries the same 1 week reccomendation as shown below, but only for salt water. I only pull it when I need to clean it or when I'm hauling out for the season. Note the part about the safety wire! Ok now. I think we've beaten this satisfactorily. The horse is dead. Operation & Maintenance CAUTION: Do not remove the screws on the top of the sensor. To remove the insert, unscrew the cap nut. This will jack the insert up. Then remove the cap nut and insert as a single unit. How the Valve Works The sensor incorporates a self-closing valve which minimizes the flow of water into the boat when the paddlewheel insert is removed. The curved flap valves are activated by water pressure. Water pushes the flap valves upward to block the opening, so there is no gush of water into the boat (see Figure 6). WARNING: THE VALVE IS NOT A WATERTIGHT SEAL! Always install the paddlewheel insert or blanking plug secured with the safety wire for a watertight seal. Using the Blanking Plug To protect the paddlewheel insert, use the blanking plug when: • The boat will be kept in salt water for more than a week. • The boat will be removed from the water. • Aquatic growth build-up on the paddlewheel is suspected due to inaccurate readings from the instrument.
Mine is an Airmar 300 series. Its about 4 years old. It also carries the same 1 week reccomendation as shown below, but only for salt water. I only pull it when I need to clean it or when I'm hauling out for the season. Note the part about the safety wire! Ok now. I think we've beaten this satisfactorily. The horse is dead. Operation & Maintenance CAUTION: Do not remove the screws on the top of the sensor. To remove the insert, unscrew the cap nut. This will jack the insert up. Then remove the cap nut and insert as a single unit. How the Valve Works The sensor incorporates a self-closing valve which minimizes the flow of water into the boat when the paddlewheel insert is removed. The curved flap valves are activated by water pressure. Water pushes the flap valves upward to block the opening, so there is no gush of water into the boat (see Figure 6). WARNING: THE VALVE IS NOT A WATERTIGHT SEAL! Always install the paddlewheel insert or blanking plug secured with the safety wire for a watertight seal. Using the Blanking Plug To protect the paddlewheel insert, use the blanking plug when: • The boat will be kept in salt water for more than a week. • The boat will be removed from the water. • Aquatic growth build-up on the paddlewheel is suspected due to inaccurate readings from the instrument.
Speedo Fouling
I have been keeping the speedo impeller clean on my 2000 H340 with a light coat of outdrive antifouling spray. For the past several years, I have removed and cleaned the speedo impeller while the boat is on the hard over the winter. Then, with the speedo back in place, I spray a light coat of Trilux or other outdrive paint on the speedo, being careful to get some on all of the blades. In three years, I have not gotten any fouling except for a very little bit of slime. Of course, I still snag an occassional piece of eel grass but that clears itself easily.
I have been keeping the speedo impeller clean on my 2000 H340 with a light coat of outdrive antifouling spray. For the past several years, I have removed and cleaned the speedo impeller while the boat is on the hard over the winter. Then, with the speedo back in place, I spray a light coat of Trilux or other outdrive paint on the speedo, being careful to get some on all of the blades. In three years, I have not gotten any fouling except for a very little bit of slime. Of course, I still snag an occassional piece of eel grass but that clears itself easily.
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