thru hull transducer placement....

looks like i may be installing a new Garmin 'echoMAP 94SV' GPS/plotter/sonar combo on my 2001 340DA in the near future....i want to avoid a haul out of the boat just to install a transom mount transducer so i will use a thru hull transducer....the deadrise on this boat is 17* which is well within the max deadrise for mounting the transducer which is 23*...

my question is where is the best location to mount the thru hull transducer in the engine room?....i have twin engines, V drive transmissions, and a generator so open floor space in the ER is limited....

thanks....
cliff

It's probably an Airmar transducer with a Garmin end on it. There should be good instructions that come with it and/or on Airmar's website. It shouldn't be directly behind a thru-hull, nor near a lifting strake. If you feel like going for a swim, you can take some quick measurements as to where the strakes are. You can use a baggie filled with water or even something like KY Jelly to experiment with locations before making anything permanent. Something to keep in mind... your deadrise at the TRANSOM is 17*, but the deadrise will start in increase as you move forward. Just make sure you don't go too far forward. I've always done thru-hulls (as opposed to a shoot-thru) or transom mounts so I've never had to figure this out. Sea Ray may be able to tell you how far forward you can go.

When I installed mine I emailed SeaRay with my hull id and they sent me instructions on where to install it.

a P79 (which most use for In-Hull) will have a hard time shooting through the glass on the SR. I have an M260 "in-hull" a much bigger one and that still have some issues on my 310.

So arm yourself with patience and get a friend to help. Sail to at least 100' of water - drop the ducer in the water from the swim platform and see how strong the returns are. Then put the ducer in a plastic bag filled with water - zip tie it so water stay in place - and then start experimenting in your bilge with where you get as good return or as close as you did in open water. Check both with 200 and 50 kHz!!!

Once you find a spot - outline it with masking tape - and take the bilge paint off - that helps too. Leave surface nice and clean. Then slighty ruff up the edges where it will be attached with 80 grit sand paper. Then fasten with 3M 4200 if you want to take it off later - or 5200 if you want it to really stick...

But quality will NEVER be the same as a Thru-Hull mounted transducer. (So with a hole drilled....) - best option for 30'+ is actually a transducer with faring to lower it below the hull water passages. That will give the best image of them all. But I already have 2 of those....

thanks for the replies.....

as i think about this more i don't realy want to spend several hundred $$ to have the boat hauled out and the hole drilled in the hull and the transducer mounted....this would start to run into some serious money for something that in reality is not a neccessity for us to boat on an inland lake once you consider the cost of the unit and transducer and the cost to mount the transducer....

is there a way to mount a tranducer to the transom while the boat is in the water that would not involve drilling holes through the transom below the water line?....if so i could run the cord up the transom under the swim platform and drill through the transom above the water line and seal the hole....

cliff

i think i have a solution to my issue....i am going to give up the 'downVu' and 'sideVu' feature (for now) on the new unit so i will not need a new transducer installed...i will still have a 9" screen and modern GPS/plotter capability.....if i decide to add a transducer for sonar in the future it will be easy to connect....i can continue to use the Raymarine Tri-data that shows the water depth, water temp and speed for now along with the new GPS......

as an interesting side note, i looked at dedicated Garmin GPS/plotters without sonar.....the GPSMAP 741 is priced about $200 more the echoMAP 94SV...the 741 has a 7" screen and the 94SV has a 9" screen.....the 741 has the inland lake maps preloaded...the inland lake map cost around $150....i called the Garmin tech line to discuss how i could buy a GPS/plotter with a 9" screen and a 'inland lakes' map card cheaper than a GPS/plotter with a 7" screen and preloaded maps.....basically at the end of our discussion the tech agreed that for basic GPS/plotter operation the 94SV without a transducer and the lake map card is a better deal than the 741...he did say the 741 has a touch screen while the 94SV has push buttons....and the 741 has the ability to be connected to other navigational equipment and it has a faster processor than the 94SV...personally for my needs i will take the 2" larger screen of the 94SV any day over the other 'features' the 741 has and for a cheaper price....

cliff