I would like to add a speed through the water readout to my 37' sailboat this year. I have a 3 year old Axiom 9 mfd. At that time I had installed an Airmar depth only transducer, the least expensive one I could find. It works well. Last year I bought an Airmar st800 speed/temp transducer but with wires/spade only output. Airmar says I'd need a $300 translation box to use it. Another option is buying a new Airmar dst 810 for about $300 which does both. It looks like it might fit into the same thru Hull fitting. I'm wondering if it would give as good a depth output as I now have. Any thoughts?
Adding Speed
- Thread starter DanMaine
- Start date
I’m guessing the 810 would fit in the same thru hull as the 800, but Airmar should be able to say for sure. The dimensioned drawings look basically identical.
We have a DST800 and the depth works just fine. I can’t say I’m impressed with the durability of the rest of the instrument - the flap to keep water out has failed twice (once under warranty and once shortly after), and the temperature sensor has gone far off calibration. But Airmar is pretty much the only option around.
We have a DST800 and the depth works just fine. I can’t say I’m impressed with the durability of the rest of the instrument - the flap to keep water out has failed twice (once under warranty and once shortly after), and the temperature sensor has gone far off calibration. But Airmar is pretty much the only option around.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,966
Dan, Depending on where you placed the Depth transducer you may be able to install the duel Airmar unit. The speed (multi transducer) is optimally located near the base of the hull near (to the side) or forward of the keel. A depth transducer is less picky about water flow location.
If money is not a factor, just install both. You'll have a depth backup for when you have to pull the speed transducer for the frequent cleaning needed.
If money is not a factor, just install both. You'll have a depth backup for when you have to pull the speed transducer for the frequent cleaning needed.
@Ward H and I both exchanged the ST800 for the DST 810. The new transducer does not fit in the old thru-hull. But, the thru hull that comes with the instrument does fit into the hole when you remove the old thru hull. I was worried that I would have to expand the hole, but Ward had done it earlier and found that it fit the hole very nicely without any modification. He and I installed mine, also with no difficulty.
We simply removed the transducer and then we cut out the nut on the thru hull with a multi tool. I found that it was extremely difficult to remove the nut because I could not turn it, probably because it was sealed in place. Don't bother to try to preserve it. It's much easier to simply cut the nut off and then punch the thru-hull out. We did have to punch it gently from the inside with a soft-face hammer to get it started. Once I could fit a stiff blade or pry between the hull and the flange, I worked it out that way. We didn't want to just punch it with brute force and risk damage to the fiberglass.
Clean up the hole and you should be ready to insert and seal the new thru hull! I don't think there is any reason to question the accuracy of the depth output.
We simply removed the transducer and then we cut out the nut on the thru hull with a multi tool. I found that it was extremely difficult to remove the nut because I could not turn it, probably because it was sealed in place. Don't bother to try to preserve it. It's much easier to simply cut the nut off and then punch the thru-hull out. We did have to punch it gently from the inside with a soft-face hammer to get it started. Once I could fit a stiff blade or pry between the hull and the flange, I worked it out that way. We didn't want to just punch it with brute force and risk damage to the fiberglass.
Clean up the hole and you should be ready to insert and seal the new thru hull! I don't think there is any reason to question the accuracy of the depth output.
@DanMaine I just re-read your post and I made the assumption that you were replacing a speed transducer. Now I see that you installed a depth transducer and then bought a ST 800 transducer. It's not clear to me which of the two you intend to replace. I don't know if the ST 800 or the DST 810 fits in the body or the hole of the depth transducer that you say is installed. But since you have a functioning depth transducer (and display?), I would simply leave that in place and if you haven't made a home for the new speed transducer, then make a new hole to install the DST 810. That would be my solution. There is no sense in eliminating a perfectly good depth instrument just to put in another, even if the new one is more up-to-date electronically. A back-up depth reading is always desirable. I don't see any sense in having 2 paddle wheels, however. They just need to be cleaned frequently and you will only double that undesirable task! You have GPS speed for back-up so that's good enough in my eyes.
Thanks everyone.
I decided to get the analog/digital box, keep the working depth Transducer and cut out the old speed transducer to replace it with the 800 I already have. Why is it so complicated?....
I decided to get the analog/digital box, keep the working depth Transducer and cut out the old speed transducer to replace it with the 800 I already have. Why is it so complicated?....
