I'm planning to install a transom-mount depth sounder inside the hull just forward of the keel to minimize the effects of pitching on the depth reading. The best spot appears to be under the floorboard in the V-berth beside the porta-potti. However, I'm seeing finished fiberglass hull liner in this area and not the bare inside of the hull skin, so I'm afraid there might be an air gap between the liner and the hull skin. I'm going to embed the transducer in epoxy, so there's no room for error. Has anyone installed a depth sounder transducer (either conventional through-hull or shoot-through) in this area? Is there an air gap? The closest unlined location I found in the archives was in the cockpit locker under the starboard quarter berth, about a foot off the centerline. I'd prefer to be forward of the keel if I can. Thanks in advance for your help. Peter H23 "Raven"
Transom-mount depth sounder inside hull
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Cheap test.
Peter: Go to your local home improvment store and purchase a wax ring for a toilet. Push this down on the inside of hull where you want to epoxy in transducer. If it works you can epoxy it in place, if it does not, then you can move it and try again. Some sailor just leave the wax there for the duration.
Peter: Go to your local home improvment store and purchase a wax ring for a toilet. Push this down on the inside of hull where you want to epoxy in transducer. If it works you can epoxy it in place, if it does not, then you can move it and try again. Some sailor just leave the wax there for the duration.
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Jason Patterson
Modeling clay
When I mounted my transducer I also used modeling clay. It works great! I mounted mine under the v-berth. If you have a wing keel there is 800 lbs of cast iron it would have to go through. This is just a suggestion. Happy sailing! Jason "Slapshot"
When I mounted my transducer I also used modeling clay. It works great! I mounted mine under the v-berth. If you have a wing keel there is 800 lbs of cast iron it would have to go through. This is just a suggestion. Happy sailing! Jason "Slapshot"
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Hayden Jones
I tried to mount my transducer under the V
birth but could get a reading. Be sure to test it before you epoxy. It's easy. Partially fill a zip lock bag with water. Place the bag agains the hull where you wish to mount the transducer (be sure the boat is in the water or you may mess up the transducer). Then place the transducer inthe water, turn on the deiplay and see it you get a reading. If not, move the bag around until you get a reading. The you can epoxy the transducer to the hull. I had to mount mine in the starboard quarter, next to the water balast tank (Hunter 23.5). It's aft farther than I'd like but I avoided driulling any holes inthe boat and it works great. Remember, the reading you get will be below the actual water line. It will provide the depth fromthe boats bottom rather than from water level as a transom mount does. I have to add nearly a foot to the reading. It took me 20 to 30 minutes to find the spot and run all the lines. Then I had to wait 90 minutes for it to dry for use. Be sure to clear all the bubbles you can before it dries. I put it all inplace, including the epoxy and made sure it worked before the epoxy dried. Sail magazine has a pretty good write up inthe May 2002 edition on mounting through the hull transducers. They show a puck type but it worked on my transom mounted type. Good luck. Hayden
birth but could get a reading. Be sure to test it before you epoxy. It's easy. Partially fill a zip lock bag with water. Place the bag agains the hull where you wish to mount the transducer (be sure the boat is in the water or you may mess up the transducer). Then place the transducer inthe water, turn on the deiplay and see it you get a reading. If not, move the bag around until you get a reading. The you can epoxy the transducer to the hull. I had to mount mine in the starboard quarter, next to the water balast tank (Hunter 23.5). It's aft farther than I'd like but I avoided driulling any holes inthe boat and it works great. Remember, the reading you get will be below the actual water line. It will provide the depth fromthe boats bottom rather than from water level as a transom mount does. I have to add nearly a foot to the reading. It took me 20 to 30 minutes to find the spot and run all the lines. Then I had to wait 90 minutes for it to dry for use. Be sure to clear all the bubbles you can before it dries. I put it all inplace, including the epoxy and made sure it worked before the epoxy dried. Sail magazine has a pretty good write up inthe May 2002 edition on mounting through the hull transducers. They show a puck type but it worked on my transom mounted type. Good luck. Hayden
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Tom Wootton
Aft location might be better
Forward locations are often subject to turbulence from the bow wave. Rough seas and heeling make it worse. The usual reason for seeking a forward location ("early warning") is not really valid if you do the math. At 6 knots, the boat is moving at 10 feet per scond. At most, you'd get an extra 1.5 seconds of warning on a 23 footer.
Forward locations are often subject to turbulence from the bow wave. Rough seas and heeling make it worse. The usual reason for seeking a forward location ("early warning") is not really valid if you do the math. At 6 knots, the boat is moving at 10 feet per scond. At most, you'd get an extra 1.5 seconds of warning on a 23 footer.
WOW Tom.
Tom: Never thought about it those terms (ft/sec). But if you are creeping into an anchorage (low speed 1-3 kts/mph) every second helps. This is especially true with a 5-6' keel. I just got new instruments for my H'31 and they happen to recommend that you put all your transducers ahead of the keel (approx 18"). Obviously this is more of an issue with a knot meter but the water that passed by the keel will give you a false reading. Now with that said, I will need to tell you that my depth sounder is ahead of my keel now and where we are in very rough seas we have gotten false readings too. So I guess the distance is critical too far forward is not good either. Different schools of thought, Food for the brain.
Tom: Never thought about it those terms (ft/sec). But if you are creeping into an anchorage (low speed 1-3 kts/mph) every second helps. This is especially true with a 5-6' keel. I just got new instruments for my H'31 and they happen to recommend that you put all your transducers ahead of the keel (approx 18"). Obviously this is more of an issue with a knot meter but the water that passed by the keel will give you a false reading. Now with that said, I will need to tell you that my depth sounder is ahead of my keel now and where we are in very rough seas we have gotten false readings too. So I guess the distance is critical too far forward is not good either. Different schools of thought, Food for the brain.
Thanks for your replies
Especially the zip-loc bag trick. The main reason for mounting just forward of the keel is because locations far forward (front of V-berth) and far aft (transom) move up and down a lot more than the center of the boat when it's pitching. Flow around the hull also tends to be more turbulent in the aft half of the hull. Good comment also regarding speed in feet per minute. I guess under the starboard berth might not be so bad. Besides, I can go in through the storage locker under the settee in the cabin intead of squeezing my 6'-2" bulk into the cockpit locker. Wish me luck. Peter H23 "Raven"
Especially the zip-loc bag trick. The main reason for mounting just forward of the keel is because locations far forward (front of V-berth) and far aft (transom) move up and down a lot more than the center of the boat when it's pitching. Flow around the hull also tends to be more turbulent in the aft half of the hull. Good comment also regarding speed in feet per minute. I guess under the starboard berth might not be so bad. Besides, I can go in through the storage locker under the settee in the cabin intead of squeezing my 6'-2" bulk into the cockpit locker. Wish me luck. Peter H23 "Raven"
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Tom Wootton
Steve, good point about marinas...
...and I might see it differently if I had a fixed keel instead of a centerboard.
...and I might see it differently if I had a fixed keel instead of a centerboard.
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Mike Pajewski
RTV
I mounted the transducer that came with my GPS/Fishfinder aft of the ballaast tank using RTV. I used the water bag trick to make sure I could shoot through and it worked perfect. Mike Pajewski H26 "Loon"
I mounted the transducer that came with my GPS/Fishfinder aft of the ballaast tank using RTV. I used the water bag trick to make sure I could shoot through and it worked perfect. Mike Pajewski H26 "Loon"
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Ken. Shubert
Just Testing
For a temporary test use KY Jelly.... just like the ultrasound medics do and you can clean up with water unlike grease or wax. RTV works very well as a permanent bond and is easier to remove than Epoxy if the situation should arise. There's always a possiblity of some irregularity in the hull that would cause problems so what works fine in one boat may not work too well in the next. Testing is simple. Ken S/V WouffHong
For a temporary test use KY Jelly.... just like the ultrasound medics do and you can clean up with water unlike grease or wax. RTV works very well as a permanent bond and is easier to remove than Epoxy if the situation should arise. There's always a possiblity of some irregularity in the hull that would cause problems so what works fine in one boat may not work too well in the next. Testing is simple. Ken S/V WouffHong
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