Where did it go???

[Neo]

Hi Gents,

Just wondering if you could help solve this mystery
Dropped my Mac in the water last week. Filled the ballast tank and headed out on the lake. On the third day I had engine issues and had to limp back to the ramp about (15Klm/10miles) at about 4 knots. With all the fuss I forgot to open the ballast vale along the way back and ended up putting my Mac on the trailer like that. Then the Admiral said "Have you emptied that tank?" ... When I approached the the Ballast Vale I expected a huge gush of water and there was no water dripping off the brand new vale. But when I opened it maybe 50 Liters/13 Gallons came out .... So my big question is "Where the hull did all the water go"???
I'd been sailing that morning and she stayed upright Ok.... My tank is open vented at the bow to the anchor locker but it's a brand new ballast vale I fitted with Sikaflex on the mounting surface.

Your thoughts guys?

All the best.
Neo

[Nauti Nell]

Water fairies...………..

[March]

Sounds like you made sure the ballast valve is fitting snugly against the hull--which is good, As for the vertical hatch door which opens within the valve itself, that is probably not watertight, nor can I thing of a good reason why it should be: the water will be "forced out" only of there is a difference in pressure (air/water) as when the boat is out of the water. When it's in, the water stays there nicely, unless inertia forces it out when motoring.
My guess would be, the water trickled out on your way back, even though the floodgate was closed...
As log as the ballast tank does not leak into your bilge, you should be ok.

[Jimmyt]

4 possibilities come to mind:
1. You didn't get it full to start with.
2. You didn't have enough pitch to drain it completely on the trailer.
3. You have a hole in the ballast tank through the hull.
4. The Admiral drained it and is now pulling your main sheet...

Follow up checks:
How windy was it? Very light conditions might not have shown a ballast problem.
So, how do you know when it's full with it vented through the anchor locker? It takes a while to fill completely - always longer than I think it should.
Did you open the valve on the ramp or after you were on flat ground?
When did your wife ask you about it? Had you driven it home?
Is there water in the bilge?

Good luck. I'd be hunting it down if it were mine.

[Neo]

My guess would be, the water trickled out on your way back, even though the floodgate was closed...

You might be right but that's a concern to me because I often motor for quite some time early morning before suddenly catching the wind later in the day. The previous valve did not like like this and the seals in that valve were in a bad way

4 possibilities come to mind:
1. You didn't get it full to start with.
2. You didn't have enough pitch to drain it completely on the trailer.
3. You have a hole in the ballast tank through the hull.
4. The Admiral drained it and is now pulling your main sheet...

Follow up checks:
How windy was it? Very light conditions might not have shown a ballast problem.
So, how do you know when it's full with it vented through the anchor locker? It takes a while to fill completely - always longer than I think it should.
Did you open the valve on the ramp or after you were on flat ground?
When did your wife ask you about it? Had you driven it home?
Is there water in the bilge?

Good luck. I'd be hunting it down if it were mine.

1. I opened the valve when I got on the water and was hosting up the mast ... it was open for an hour or so.
2. It was on flat ground but from previous experience I know the water level should have been at least half the height of the vale hole.
3. Apart from a few drips it was dry under the trailer .... Just checked the hull ... Can't see any holes or deep scores.
4. Wouldn't put it past her .... except she has no idea how to open the valve

It was Mid to light winds.... so you could be right here.... Maybe another clue here was I was getting 4.2 knots at 1,500 RPM (Mercury 50 Bigfoot / Standard Pitch 15 prop) on the way back ... which I remember thinking was quite quick but the Lake was like glass that morning.
I have a short plastic ribbon flapping over the vale entry hole. When the tank is filling the ribbon is dragged in, when it's full ribbon waves around freely.... This is a good but maybe not a foolproof method of ballast level check. I was concerned that the Venting tube had become blocked. But I checked it the next day and it's all clear.
No I didn't open the vale on the ramp slope at all.
I opened it in the Boat ramp carpark about 5 mins after retrieval.
Yes but not much...about 4 cup fulls of water in the bilge.

Thanks for sharing your thoughts and ideas Jimmy and March

[DaveC426913]

the water will be "forced out" only of there is a difference in pressure (air/water) as when the boat is out of the water. When it's in, the water stays there nicely, unless inertia forces it out when motoring.

The other factor is water level.
If he's zooming around, planing, the water will drain simply by gravity. (The ballast level will be above the waterline, since the boat would be nose up.)

In fact, motoring with the gate open is the preferred method for dumping ballast prior to haul out.

[Neo]

If he's zooming around, planing, the water will drain simply by gravity.

I did no planning in the 3 days ... nearly all was 4 knots

In fact, motoring with the gate open is the preferred method for dumping ballast prior to haul out.

After 3 years of owning my Mac and 857 Forum Posts I think I know that Dave

[dlandersson]

No, no, water gremlins ...

Water fairies...………..

[Jimmyt]

I've never tried to drain ballast at 4 knots, but that's below the manual recommended 7mph. I'm wondering whether 4 knots would have drained it - even if the valve was partially open.

Sounds like you left it open long enough to completely fill it. Ribbon telltale is a cool idea.

Not much water in the bilge, so no internal leak of any significance. I'm always puzzled by reports of water in the bilge - mine stays bone dry.

Did you notice if the valve was actually seated tight when you opened it? The more I look at your activities, the less I think the valve being partially open would matter much (regarding ballast disappearance). You were putt-putting around, so whatever might have gone out would have refilled while you were going to get the tow beast and trailer. Some might have drained out as you hauled up the ramp I guess, but you would have probably noticed if the valve was open significantly.

Have you tried tilting the nose up to see if you still have a bunch of water in it? On flat ground, my boat is actually down at the bow when towing, so it wouldn't drain completely. The bottom has considerable rocker also, so the valve is higher than a lot of the ballast tank - even when the boat is level. I crank my nose jack way up during wash down so I can spray into the ballast tank and have it drain back out.

That's about all I can come up with. Hope you figure it out.

My money is still on the Admiral. They're a sneaky lot

[DaveC426913]

I think I know that Dave

Of course. This was directed at March, not you.

[March]

[Neo]

Did you notice if the valve was actually seated tight when you opened it?

Yep it was firmly closed and water tight just before I opened it on flat ground. When opened water did come out like the level was only 1/2" above the valve opening (lowest point).

Have you tried tilting the nose up to see if you still have a bunch of water in it?

Good idea .... I'm going to pump some more water into the belly then tow the trailer up my steep driveway... then wait and watch to see what happens ... Will update you.

Of course. This was directed at March, not you.

Sorry Dave... Didn't mean to offend you

I know this looks like an unsolvable mystery but I really appreciate you guys sharing your ideas with me ... Many thanks for that.

[Jimmyt]

"I know this looks like an unsolvable mystery...". Only kind I like. Thanks for posting it.

[Neo]

Ok did the test ..... Left the Mac on the slope for 10 mins but not a single drip came out .... This is good ... but bad at the same time
Then when I opened the valve and full (valve hole size) gush of water came out.

Also checked the hull from stern to bow ... no drips.

[Jimmyt]

That all sounds good to me. No leaks anywhere.

What I don't see is how you determined that the tank was empty. You put more water in it and then put it on the slope. You opened the valve on the slope and got the flow you expected. However, you don't indicate that you measured how much water you put in to make sure more didn't come out on the slope (maybe tank never emptied completely).

Did you put it on the slope and open the drain prior to adding water? Or did you just put more water in on flat ground and then move it to the slope?

Sorry if I'm missing something. My dad always said I was not the brightest bulb in the box...

Based on what I read, it appears that your boat is fine and you proved that you can't drain the ballast when the boat is approximately level.