2 Things: Positive Pressure & Compass Oil

[GorillaToast]

Hi All.

Has anyone really tried the Positive Pressure method of detecting leaks? How airtight do you need to make the boat? and how did you get the sliding hatch airtight?

Alos, do I need to worry about the oil in my compass freezing and cracking the glass in my compass over the winter?

Thanks.

 

[Chris Patterson]

Bill, I have never tried the pressure test, but I'm familiar with it. Maybe somebody else here knows, but it seems like sealing the hatch would be a challenge. But a leaf blower makes a lot of air, so that might make up for some inefficiencies.

I have never heard of an oil filled compass freezing, and I would think it would have to be very, very cold to do that.

 

[Milton.Audas]

Re. they gauge, it should.not freeze unless there is a leak somewhere allowing moisture to enter.

Re. the pressure test, to achieve positive pressure and detect leaks the whole boat has to be tight. If the pressurised air can take the easy route, vis-a-vis the hatches or windows you probably won't find the leak in say a window seal or thru-hull. Need to run some rubber seals around the hatches and then secure them tight, and seal with duck tape. Same around the windows and for'ard hatch. Where/how do you plan to feed the positive air from ? Ducting through an exiisting vent or cowling would make sense.

Cheers

Milton

 

[GorillaToast]

Thanks guys for you replies.

Ive attached a fitting from my shop vac to a piece of cardboard that will cover the vent louvers on my crib boards. I'll attach the leaf blower via a vac hose to that.
Everything except the main sliding hatch is pretty well sealed. I'll try to find something seal it up with.

Good news about the compass. One less worry.

 

[Chris Patterson]

Dang Bill, you wintering already?

 

[Bilbo]

There may be other hatches that allow leaks like the fuel locker if older style.
One could probably use a lot of duct tape around the hatch areas and some dish detergent/water on potential leak areas.

 

[GorillaToast]

Dang Bill, you wintering already?

Yeah, Chris. I've been out since September because of the leak.

Btw, sorry I didn't make it down to see you while on vacation last month.

 

[GorillaToast]

There may be other hatches that allow leaks like the fuel locker if older style.
One could probably use a lot of duct tape around the hatch areas and some dish detergent/water on potential leak areas.

Thanks Bilbo, but I was pumping out a gal. a day with no rain for weeks. Has to be a hull leak. And yes, I've already eliminated thru-hulls, lower gudgeons, volcano, as possible sites.

 

[watercolors II]

If it runs in it will run out!

A couple weeks ago we filled a Oday 22 with fresh water on the inside to the water line and watched for the water to run out to fine the leak. When the leak didn’t appear we tilted the boat forward, backwards and sideways till the water was running out the bolts holding the bottom rudder gudgeon on. Apparently when the waves and wakes were slapping up against the stern and the bottom gudgeon at the dock is when the water was entering the hull.

 

[GorillaToast]

I rebedded the gudgeons, and motor mount, as well as the bilge pump thru-hull last winter with butyl tape. If water were enter in any of those places, wouldn't I be able to see evidence of it in the aft compartments, battery compartment, port rear dinette compartment? The only place water consistantly appears is under the head floor. Even when there is no rain, no waves, and the boat sits at the slip.

I tried the positive pressure thing this morning. I can't tell anything. The leaf blower is so loud I can't even tell if I've done a good job of sealing up the topsides.

Time to take it to the pros.

Thanks All.

 

[Chris Patterson]

Bill, have you put water into the boat, to just see where it might be coming out? Or just looked for air?
Just a thought..

 

[Merlin Clark]

Did you try brushing on soapy water GT?

 

[GorillaToast]

Yup.

I just don't think I can adequately seal the sliding hatch enough to make it airtight while it's 35 degrees outside and there's a tarp over the boat.

 

[jfrench]

Tide detergent has additives that fluoresce in UV light. The idea is to make your whites look whiter in sunlight. Perhaps fill the boat with water as suggested above, and toss in a few cups of Tide. Then wait until dark (we're having a lot of that these days), and shine a black-light around the outside of the hull. The areas where "Tidewater" is seeping out (sorry, I couldn't pass that up) would show up as bright white in the black-light. You'd also get a cleaner bilge in the process.

If you're looking for rainwater leaks, first turn the boat upside down!

 

[Chris Patterson]

French, that was wrong, man..

But funny.

 

[GorillaToast]

If you're looking for rainwater leaks, first turn the boat upside down!

Actually, there's a guy in my club that has a way to do just that - he suspends his boat between 2 trees in his yard, and can spin it on its axis. Real handy for bottom painting.

It's getting below freezing at night here, now. So, no water in the bilges til spring!

 

[watercolors II]

Leaks in the hull can appear anywhere anytime in the hull underwater and above the waterline that is so small you can not see them with the naked eye and the only way to find them is for the water to leak back out.

Just this past season a fellow at the lake sanded and bottom painted the hull on a Balboa 26, when he launched the boat in the spring, water was running in for the first time since he owned the boat. He had to remove the boat and take back home, what he found was when he was sanding the bottom he remembers using his finger nail to pick off what he thought was a small piece of putty and that is where the leak was traced back to.

A couple years ago another fellow with a San Juan 21, in the middle of the season found his boat full of water and when he bailed it out he found back under a bunk a small pinhole squirting water up about an inch in height, this was after floating at the dock for 3 months.

 

[catsailor]

Compasses are filled with oil and do not freeze.

Also, water is quite unusual in that it expands when it freezes. Nearly all other substances contract further on freezing; if the oil did begin to congeal (they do not freeze in the same sense) it would not expand.

 

[Bilbo]

Yup.
I just don't think I can adequately seal the sliding hatch enough to make it airtight while it's 35 degrees outside and there's a tarp over the boat.

If you were getting a gallon a day, then the leaf blower idea may not work for you. IF it's coming in to the hull at that rate & if it's a hull leak then the hole is really pretty small as someone described in another post.... a pinhole may give you more than that amount of water in a day. Think of it as about 1 tablespoon coming in every 6 minutes. If your boat's out of the water, I'd try putting some water into that area of the bilge and seeing if it leaks out through the hull colored or soapy water may aid in seeing it. Coming out of the hull, at best it may be a rather slow drip.....on occasion.