condensation on instruments

Xk59D · 15 August 2010, 23:44

eveing folks,

looking for some advice on a this one.

my hummingbird 757c, quicksilver fuel, trim tab, speedo gauges all develop a little misting when turned on for a little while. seems intermittent if they will clear up or not.

since all the stuff is new to me is there anything i can do to fix this problem?

FYI the boat is always stored outside with a full cover over it.

nothing major but an annoyance an a quick search shows others have had problems but no real info as to a diy fix?

cheers

BogMonster · 16 August 2010, 03:05

I think "it just happens" - not really sure why on supposedly IPX7 sealed instruments

but all the gauges on my Humber and the fishfinder display used to mist up regularly. The only thing that didn't was the Icom VHF. Never seemed to bother anything though, which is odd.

willk · 16 August 2010, 09:42

OK. In my right hand I have a Can of Worms, in my left, an Can-opener....

I had this problem with my older plotter. It had become almost useless in certain conditions. Anyway, I decided that I had nothing to loose.

I found a very small silica gel sachet (as packed in electronics boxes), dried it in the oven and placed it inside the back of the plotter housing. It worked VERY well for a few months but I now see a bit of mist reappearing. Have to go again with a drier and larger pack this time.

Plotters are not sealed, merely closed with a foam rubber O-ring (probably neoprene). As the unit warms and cools, damp air must be drawn in and when warm, the coolest, highest place for moisture to condense is the inside of the screen.

biffer · 16 August 2010, 10:25

you can get silica in little round plastic tubes, i think mine came from a double glazing company, i think 3m sealer have something like it in the bottom of the tube, drill a hole in the back of the plotter and jam it in, when it's all used, take it out and jam in another one, jam is a technical term for push in tightly

jambo · 16 August 2010, 15:35

Hi all the previous info taken can I also suggest that it is the cover that is generating the heat and cuasing the condensation as ther is no vbentilation,I have it. If it does not burn off and the sileca is taking to long, take out the bulb at the back and let it breath.I recently got a consol cover made with vents and it has stopped tyhe problem.
Hope it helps.

J

Xk59D · 17 August 2010, 08:16

i'll have a look this weekend at some options.

i'll try and find some of those silica sticks mean time.

cheers

Cookee · 17 August 2010, 13:35

Quote:

Originally Posted by Xk59D

eveing folks,

looking for some advice on a this one.

FYI the boat is always stored outside with a full cover over it.

nothing major but an annoyance an a quick search shows others have had problems but no real info as to a diy fix?

cheers

Make sure the cover is ventilated, the humidity in a sealed cover combined with heat variations are going to make it difficult for anything to cope.

Xk59D · 17 August 2010, 17:03

vented in what way?

the cover is hardly a brilliant fit with air gaps here/there?? the cover is a full boat cover if i hadn't made that clear.

cheers

willk · 17 August 2010, 17:32

Oh here, I misread your OP. I thought it was just the plotter. They're right about the cover ventilation - warm damp air rises under the cover. I have a couple of clamshell vents in my cover, up high near the console. I think a vent in the console is a plus too, that or leave the hatch open (under the cover)

SeaSkills · 17 August 2010, 17:51

On (most of) my instruments I find that if I turn the backlight up to it's max, the warmth generated by the light clears the condensation

Cookee · 18 August 2010, 08:39

Quote:

Originally Posted by Xk59D

vented in what way?

the cover is hardly a brilliant fit with air gaps here/there?? the cover is a full boat cover if i hadn't made that clear.

cheers

On a warm day when you get to the boat lift a corner up and see if any warm humid air escapes, if it does you need more ventilation. The point is cure the cause not the effect, you will never have a totally dry boat unless it never goes in the water, if you have access to power a small light bulb will provide enough heat to keep it warmer and with some ventilation that will take the humid air away.

As Willk says clamshell vents in the cover will be a start!

Poly · 18 August 2010, 09:14

Quote:

Originally Posted by Cookee

On a warm day when you get to the boat

unfortunately he's in Scotland and our one warm day was yesterday so he'll have to wait till next year!

Quote:

if you have access to power a small light bulb will provide enough heat to keep it warmer and with some ventilation that will take the humid air away.

Just be aware that because a light bulb gets hot if anything gets close to it, for several hours/days at a tiime it may scortch - or worse if e.g. the cover touches it may go up in flames

. If I was looking for an "electrical" solution I'd be tempted to get air "moving", and rather than warming it rig some sort of small fan (perhaps a computer casing fan on a solar panel).

Quote:

As Willk says clamshell vents in the cover will be a start!

and do you store it with the trunks down? (might be worth popping a bit of plumbing waste pipe in them to keep them open (as a route for fresh air in (with the vents at the top as the exit).

Xk59D · 18 August 2010, 10:23

hot day!....lol........obviously not from round these parts.

the elephant trunk does sit down but it is all but collapsed so i could maybe use something to keep it open.

if i make an opening at the front and let air go from front to back i guess that will help.

it's difficult to tell if the above will work until i go out on it again as it will not do it unless turned on and in use for maybe 15 mins or so.

cheers