Gotta do some thru-hull work, advice? (lights, temp sensor)

BlueWater

2007 246 Cuddy
I bought a blue underwater LED to put on the transom, but where?  Under the swim platform would be easiest but out of the water - anybody ever put a light shining down, AT the water but not in it?  (I realize this is probably the least important question ever asked on this forum ) :-)
Also have a seawater temp probe to install.  Would really like some advice on drilling techniques, placement, sealant methods, sealant products, etc.  Planning to do all with boat in the water. HA! just seeing if you are paying attention...
Thanks in advance

Willhound

Your light will work above water, just not as bright and you won't get much effect especially in murky water. As to the temp sensor...if you already have a Chartplotter/GPS/aftermarket Sonar, these quite often have water temp so no need for a second sensor. But if you absolutely have to, I'd run the wires through the transom above the water line, just below the swim platform and run the wires down and mount the sensor on the outside of the hull. You won't see the wires under the platform anyway and can use little screw on clips to keep them in place. The transom at this point is almost 1 1/2" thick or more so just use 3/4" stainless screws and sealant/adhesive like 3M 4200.

LaRea

Which temperature sensor?

BlueWater

"Which temperature sensor?" - a Blue Sea Systems 1820:
https://www.bluesea.com/products/1820/Submersible_Temperature_Sensor

LaRea

Oh - I have one of those for monitoring battery temperature.  That's not a good choice for outside the hull.  It's too fragile to survive that environment, and the sensor does not have mounting holes for screws.  

BlueWater

Good to know.  I thought I read somewhere that aftermarket sensors can be used with this gauge?  Or do you have another to recommend?

LaRea

Which chartplotter do you have?  Or do you have a separate sea water temp gauge?

BlueWater

No chartplotter, just the temp sensor/gauge as listed above
""Which temperature sensor?" - a Blue Sea Systems 1820:
https://www.bluesea.com/products/1820/Submersible_Temperature_Sensor"