Newbie ? about water ballast

[davidb]

The Commodore and I just took my newly acquired 1995 Hunter 23.5 out for the first time. We were mostly successful, but could not convince ourselves that the water ballast tank had filled completely.

How much water should there be in the ballast tank? After 10-15 minutes (tied to a dock), we only appeared to have about 3"-4" in the tank, with about 9" of air space from the water level up to the vent hole. Is that full, or should there be more water in the ballast tank than that?

If that is not full, what could have been keeping the ballast tank from filling?

Thanks in advance for your help.

David

 

[VT Fitz]

How could you tell...

there was only 3"-4" of water was in there? I can't see to the bottom of my ballast tank. In any case, 9" air space from the top of the vent hole sounds like not enough water.

Perhaps the plate on the hull isn't pulling away. Is there bottom paint? Maybe it was "painted on" and now can't break away.

I'd try loosening & pushing down on the big wing nut and see if you feel any play. (But don't remove the split ring on the top of the screw! You don't want to loose the whole thing to the bottom.) Alternatively, you can grab a swim mask & go look.

However, it is somewhat perplexing, because if you have any water in the tank, there is no reason it shouldn't have filled all the way. Did you remove the vent plug while filling?

It is very dangerous not having a full ballast tank. You should not sail her until you're positive it's full.

 

[owner23.5]

I know the seal on my fill plate is failing as when I pull the boat out of water with the plate tightly closed it will still release the ballast tank , so this in mind my tank will allow water into ballast tank while still shut and sitting at the dock, when I pull the plug inside I see the water line about 7-9" below the vent hole , so must be the right length your talking about .

 

[gfroch]

I'm not sure about the 23.5, but my 26 fills right up to the top (within an inch)

 

[soling42]

Dave,
That tank MUST be full and sealed tightly. Anything less and your boat will be a hostile winch that borders on psychotic. I don't know how upset I'd be about it leaking a little on the trailer if it's full(it really shouldn't be full out of the water unless your trailer is a massive brute).

"Full" will depend on how much gear you have on board. When I'm loaded for a week long cruise mine would over flow with the vent out. If you havn't experienced the insidious creep of unneeded gear then it could be down in the vent a few inches at the most. The 23.5/240/26/260 all have the same fill system so it won't vary much(if any).

When I'm emptying mine on the ramp I personally like to announce that my beer drinking crew REALLY filled the holding tank this time

Here's a pic to visualize the dynamics of a water ballast boat. Also a page from the manual for the tank details. There's no room for air to slosh around if it's working right. Be safe, keep it full and seal it tight and go have fun in your new ride. Congrats, Mike and Kelli

 

[davidb]

Re: How could you tell...

VT Fritz,

Thanks for your reply.

I was able to unscrew the wingnut out to the split ring that keeps it from coming off the end of the bolt, and then was able to move the wing nut & bolt a couple of inches in and out, so I'm pretty sure the plate was not stuck to the bottom. In addition, when I pulled the boat out of the water (I dry-sail her), I deliberately kept the ballast tank inlet closed. Then, after I had her completely clear of the water, I opened the inlet, and a significant amount of water immediately began dumping out and running down the ramp.

When I measured the water level (as stated in my original post), I was tied to a convenient dock. By this time, the boat had been in the water with the inlet open 15-20 minutes. I wasn't smart enough to bring a flashlight with me on this outing (who needs a flashlight at 8:00 AM?), so I tested the water level by sticking a long stick into the vent hole, then observing how much of the part that went down into the tank was wet.

I agree that there's no good reason for the tank to fill only partially. However, I'd feel a whole better if another Hunter 23.5 owner could positively confirm that what I'm observing indicates a full tank, or that I have a problem I need to chase down before I go out again.

Your signature indicates you also have an H23.5. How high is the water level in your ballast tank?

 

[davidb]

Soling42,

Thanks for your reply also.

I have looked at the picture you attached in the manual, but perhaps didn't notice a detail that might help resolve my concern.

If I look at the area around the wing nut in the diagram, then follow the top of the tank to the right, I notice that it quickly makes a 90° (more or less) turn downward. It goes down for a ways then makes another bend to become horizontal,

 

[davidb]

Dang it - sent of the previous post before I was through with it!

To resume...

If I look at the area around the wing nut in the diagram, then follow the top of the tank to the right, I notice that it quickly makes a 90° (more or less) turn downward. It goes down for a ways then makes another bend to become horizontal, proceeding to the right off the edge of the diagram. If the construction on the H23.5 is close to that of the H240 (pictured), then I have just about convinced myself that the part that proceeds off to the right is in fact the top of the main part of the ballast tank. The proportions of the space under the wing nut would pretty much explain my observation. I'll have to go double check the corresonding picture in my H23.5 manual to see if it looks the same.

 

[soling42]

Here's another pic of a tank being installed. Your tank will fill in no more than 8-10mins. If in doubt about whether it's blocked or screwed up, check the bottom plate at the ramp or with a mask/snorkel. My old 240 would leak down if the vent wasn't sealed tight but otherwise it's impossible if the vent's in right and the thread for the wing nut's not sucking air.

Load some folks carefully on the boat while she's filling/nearly full but still tied to the dock to see the water level rise at the vent. She'll be tender but won't flip or anything completely unpredictable within good sense. When it stops blowing out air that's all you'll get. I suspect she's just a lightweight without all the provisions she'll get over the next year.

Have fun.

 

[Deucer]

The simple physics of water ballast is that if there's a hole in the bottom and hole in the top, the water will rise until it matches the water level at the water line. No more, no less (this is what Solvang42 is describing by putting more weight on the boat...makes it set deeper; hence, more water in the tank.).

So long as the ballast valve is operating properly, you should be getting enough water in the tank. What I don't know is, but bet the answer is empty, is at what displacement the tank is designed to ingest enough water ballast.

Oh, and the water doesn't come all the way to the top of my vent, either. But you can hear the splashing (some times get wet) when filling the tank.

 

[owner23.5]

went down and checked mine tonight for ya , " marinas across the street" anyway measured with pencil and was about 5inches before the end got wet and know my tank is full , good luck

 

[VT Fitz]

Too far away to check

David

Boat's in CT; I'm in VT, so can't check till the weekend. 9" sounded low, but as others have suggested, if the plate is working freely, the water will find it's proper level, so I'm inclined to think you are good-to-go.

However, I was wondering why you don't open the drain before pulling out. I like having the ballast start to drain ASAP. The less stress on my tow vehicle the sooner, the better.

 

[cephius (Dave)]

The tank fills very quickly. Within a couple of minutes. You can feel and hear the air rushing out the vent. No options. It really doesn't matter what level you measure, there is nothing to prevent the tank from filling to its capacity. If you got that initial rush, then have confidence that you have a full tank.

 

[DJN51]

On my 95 23.5 after launch it take about 10 min to fill.Looking thru vent hole,water level is about 3 in down from vent hole.I'm slipped and even after 40 daysails i opened fill valve and got just a puff of air out of vent hole so it must be full,Next slip over 93 23.5 same result.Good luck.You'll love your boat.

 

[RocklockI]

I sailed my Hunter 23.5 for the first time yesterday so I had the same question .

I opened the seacock and pulled the vent plug , air rushed out of the vent for about 5-7 mins . The water level was not within reach of my finger but not by much . I left it uncocked for a couple more mins .. then sealed her up .

Darn she sails very nice , but light like a bobber .

Gary

 

[VT Fitz]

You're fine

I think all this hand wringing about how many inches of gap is irrelevant. It's probably solely a function of how much "extra" ballast you are carrying, i.e. equipment, provisions, gravity-challenged crew, etc.

Not sure what you mean by "bobber," but the high freeboard does present a bit more windage. Also helps keep you drier!

 

[Vern23908]

Deucer - I've had my H260 since new in 2004. Even though I think of myself as a scientifically minded person, it never occurred to me to reopen my ballast valve with the boat loaded. Except for my initial launch in 2004, I've always had the marina staff do it for me when they launched it in the spring. I'm sure it was with only one person on board. With the size of my crew, I'm sure I could get just a small bit more stability opening the valve with a loaded boat. Thank you for your post.

 

[RocklockI]

A bobber in that as soon as we cast off with no sail up she just stared off on her own ! blowing across the water . 10 mph wind .
Gary

 

[Deucer]

Gary,

Welcome to high freeboard boats. Has little to do with where you're ballast is located (i.e., which weighs more....2000lbs of water or 2000lbs of lead?). Just another bit of sailing trivia. The keel (as in the fin) is primarily there to keep the boat from being pushed sideways by the wind. It's a bonus when you put weight in the fin (or in a bulb keel, on the bottom of the fin). It's all about leverage. It's also the reason water ballast boats tend to be tender at first than stiffen up at higher heel angles. All you have to do is draw a picture of where the axis of rotation is located vs. where the weight is located.

 

[Deucer]

Explaining this post with the admiral made me realize another piece of the obvious. Since a boat displaces it's weight in water, the difference between a light boat (no equipment, one person) and a full boat (loaded with a crew) should be pretty close to the difference in your ballast if the fill valve is open. This could make a difference on 10% or more in the weight of your ballast. I'm not 100% sure about this, but it sure sounds right.....

So, here's something for somebody to try. Fill your tank with your normal load on board, then go sailing. Then go back and put a heavy load on the boat, top of the tank, then remove the extra weight. Go sailing and see if there's a difference in the way the boat handles. Guess you could see if the boat sets lower in the water. I don't know if you can load the boat so much as to force the air vent lower than the waterline...that would be bad...very bad....