water vs. mineral oil for shoot thru hull transducer tube?

[chiroken]

Any feedback/experience on whether or not mineral oil works any differently than water when used in an enclosed container holding the transducer for shoot thru applications? Particularly for fish finding accuracy. I will be using 6" pipe with the transducer mounted just off the floor of the engine well. The bottom of the pipe is cut to match the slope (15^) so that the pipe will be vertical and the bottom of the transducer will be horizontal to the water's surface.

I am reading that people use 1 or the other but no info if one is superior to the other. Water is easiest but I will use mineral oil if it gives better results.

Thanks.

 

[seabob4]

Re: water vs. mineral oil for shoot thru hull transducer tube?

I've installed a ton of Airmar shoot-throughs. Calls for mineral oil, never sen one that recommended water...

 

[dingbat]

Re: water vs. mineral oil for shoot thru hull transducer tube?

Direct From Airmar
http://faq.airmar.com/index.php?action=artikel&cat=1&id=12&artlang=en&highlight=glycol

What type of liquid do I use to fill my in-hull tank/base?

Non-toxic propylene glycol(RV antifreeze/coolant) should be used to fill an in-hull tank/base.

M260 tanks should only be installed with fiberglass resin, Marine-tex epoxy putty, or Fusor T10 EZ. On our newest tanks that have "gf nylon" printed in raised lettering on the sides, 3M's 5200 may also be used to adhere the tank to the hull.


The P79 base may installed with silicone sealant, fiberglass resin, 3M's 5200, or Marine-tex epoxy putty.



NOTE: Do NOT use mineral oil to fill a tank that is secured with 3M's 5200. Mineral oil may weaken the bond. Only use non-toxic propylene glycol(RV anti-freeze) when using this adhesive.

 

[seabob4]

Re: water vs. mineral oil for shoot thru hull transducer tube?

Some interesting comments from an '04 thread on THT...http://www.thehulltruth.com/boating-forum/15830-mounting-transducer-bilge-mineral-oil.html

Seems Airmar USED to recommend mineral oil...

 

[PBarrett]

Re: water vs. mineral oil for shoot thru hull transducer tube?

You can certainly use water if you wish. The reason RV Anti Freeze is recommended is that it does not evaporate and is compatible with most adhesives. Mineral oil used to be the preferred liquid, but it tends to break down certain adhesives. As far as which one "works better", none of them will help you see more, or less, fish.

PB

 

[H20Rat]

Re: water vs. mineral oil for shoot thru hull transducer tube?

You can certainly use water if you wish. The reason RV Anti Freeze is recommended is that it does not evaporate

rv antifreeze evaporates quite readily... Water is the #2 ingredient, and after it evaporates you end up with a pink sludge that can sometimes clog things up.

 

[smokeonthewater]

Re: water vs. mineral oil for shoot thru hull transducer tube?

if you use plain water you will need to drain it if it will be exposed to freezing temps

 

[chiroken]

Re: water vs. mineral oil for shoot thru hull transducer tube?

Thanks for all the info so far. Locally everyone seems to use Sikaflex, Sikaflex-291 is what I've bought. Don't really see 4200 or 5200, wondering if that is more of a US product and not up here in Canada? Didn't think about mineral oil breaking down the adhesive, abit of investigative work ( http://www.sika.com.au/cmi/pdfs/TDS_Sikaflex291.pdf)came up with:

"Chemical Resistance:
Sikaflex?-291 is resistant to fresh water, seawater, limewater, se-wage effluent, diluted acids and caustic solutions; temporarily resis-tant to fuels, mineral oils, vege-table and animal fats and oils; not resistant to organic acids, alcohol, concentrated mineral acids and caustic solutions or solvents."

Looks like it may be eventually broken down by the mineral oil. Can't say I can understand the link I gave as to whether or not RV antifreeze would work and not break it down. Can anyone help here? It will freeze at times here during winter and would have to remember to remove the transducer (or drain the water) during storage.

I did come up with a better option to mount the transducer to the pipe. I was going to use the transom mount hardware through the side wall of the pipe and sikaflex the holes but I now realize I can rotate the mounting bracket 90 degrees and mount the transducer through the pipe cap. Much less likely to leak and easier to do. Cut the pipe and cap so that the transducer will sit just above the engine compartment floor.

 

[PBarrett]

Re: water vs. mineral oil for shoot thru hull transducer tube?

rv antifreeze evaporates quite readily... Water is the #2 ingredient, and after it evaporates you end up with a pink sludge that can sometimes clog things up.

Not true! I have used it for years and have NEVER seen it evaporate. Read the following spec sheet;

Physical Properties

According to the Material Safety Data Sheet (MSDS) for propylene glycol, it's a colorless liquid with a slightly sweet taste and is notably more viscous than water, meaning that it flows slowly, like syrup. Its melting point is -72.4 degrees F, and its boiling point is 370.8 degrees F. It has a specific gravity of 1.036, meaning that it is only slightly more dense than water. Its vapor pressure at normal room temperature is negligible, so propylene glycol does not evaporate to any significant degree.


PB

 

[Texasmark]

Re: water vs. mineral oil for shoot thru hull transducer tube?

Why not mix up some epoxy and make a horizontal pad using that 15 degree tube you are talking about....just make it thick enough to get your horizontal dimension, and obviously discard your tube when finished, or just cut it off just above the floor horizontally, fill it with bubble free epoxy, and leave it there. Then, after it firms up, mix up a little more and putting a thick, bubble free film on the "pad" glue down your transducer.....then forget it!

"Sonar" is acoustic and operates off vibrations produced by sound waves. The harder the medium (regardless of the material) the better the transmission "power out"/"receiver sensitivity" (for a given system) if you will.

Mark

 

[dingbat]

Re: water vs. mineral oil for shoot thru hull transducer tube?

Some interesting comments from an '04 thread on THT...http://www.thehulltruth.com/boating-forum/15830-mounting-transducer-bilge-mineral-oil.html

Seems Airmar USED to recommend mineral oil...

A lot changes in 7 years. I'm one of the ones that got caught with leaking mineral oil when it first came out. I contacted Airmar and was told to switch to caster oil which I did. The caster oil did the job for the next two years before I sold the boat. When with thru-hull this time around. Much better performance.