Capacity Issues for Camping Trip

[JeffM]

Ballast doesn't care where the water line is--unless that ballast is sometimes displaces water and sometimes not, like the Sea Pearl's lee boards. The point of having ballast in the cb is that, with increasing angles of heel, that ballast provides increasing righting moment. And keeping that ballast amidship allows the boat to respond more quickly to waves, etc.

[Ken_Potts]

Jeff,

The way I understand it water ballast is a little bit different than lead ballast because of the density. If water ballast were added to the centerboard (and I don't think you were suggesting this :wink: ) it would not begin to have a countering effect to a rolling boat until the centerboard was raised above the water line. As long as it is below the waterline it is neutrally bouyant.

I realize I may be incorrect in my thinking or I may not be stating things clearly but I do think that water ballast needs to be set as far from the fore-and-aft centerline of the boat as possible.

Dense stuff like lead ballast should be treated differently than neutrally bouyant water ballast.

[Garry]

What matters is the center of gravity of the additional ballast in relation to the center of bouyancy of the hull. It is the horizontal difference between COG and COB that creates the righting moment. It does not matter where the water line is, that effect is accounted for in the center of bouyancy. As the boat heels, the COG is fixed but the COB moves to leeward and tries to force the boat back upright thus resisting the heel.

Water ballst on Graham's boats will necessarily be near the center of bouyancy and therefore have little effect on righting moment. Lead in the bilge will have a little better effect than water ballast because it will lower the COG more than the water would. A few pounds of lead on the tip of the centerboard will have a great effect because it is much lower.

Of course, the centerboard must be designed for the loads.

Moveable ballast (crew) has a much greater effect because it changes the center of gravity to the windward side. Water that is moved from one side to the other would also have great effect (except for those awkward moments when tacking or gybing).

[brigait1]

I agree with Garry that lead on the centerboard is ideal for improved righting moment. If that is the only consideration, you have to go with lead. The real issue with water ballast IMHO is flexibility. For example, if you use your CS for daysailing 95% of the time, you will likely want to keep it as light as possible. But on thise occasions that you go for extended excursions in which conditions may vary quite a bit, it might be nice to be able to fill the ballast tanks when conditions warrant it.

If my thinking is way off here, someone please chime in.

Pete

[Tom Lathrop]

I've noticed several people mention that the CS-20 gets much more tame with a load. Has anyone out there experimented with water ballast for rougher conditions. It seems like I've read somewhere that similar boats like the Sea Pearl do this.

Any thoughts?

Pete

The Sea Pearl has very little in common with a Core Sound other than they are both cat ketches. A Sea Pearl has very little form (hull) stability while a CS has a lot. Step aboard a water ballasted Pearl without ballast in the tanks and you will see what I mean. Even fully ballasted, the Sea Pearl is not near a CS in initial stability.

Even if a boat has bilge tanks, the righting moment is the same as if the water were all at the geometric center of the two tanks. Righting moment actually starts as soon as the boat is heeled, whether the ballast is lead or water. Even it you have a chunk of stuff in the bilge that is lighter than water, it adds to the righting moment when the boat heels. If it weighs more than air, its ballast. Lead or, better yet, depleted uranium is best.

[Ken_Potts]

Thanks guys, I think I understand where I was going wrong about water ballast. I was sort of talking about one thing while visualizing another but basically I was wrong

If you're afraid of the possible hazards of depleted uranium you can look for a little unobtanium - I believe it's somewhere between 17 and 158 times as dense as uranium. A dime-sized piece should be more than enough

I think I'll be relying on the reefing-step for rough stuff (though I plan to avoid the rough stuff).

[capt jake]

OK' date=' If Cap Jake see's this post his jaw will hit the floor!

And I may well lose my title given to me as "The Ballast G-d"

I don't see any reason for putting ballast on a CS 20.

Plenty comfortable in my estimation without.[/quote']

WHAT??? Ray....stating that a boat needs no ballast????? Send out the rescue squad to check on him; I think he has been affected by polyester resin or something! ;) Wait, it could be the depleted Uranium is finally showing it's effects. LOL :shock:

[Tom Lathrop]

Ray, Jake,

You might look for a speck of negrovoidium. A cubic micron should be enough to sink the boat or drop right through the bottom so a proper amount would need to be milled by laser under a microscope. It should then be attached to a small plate of that unobtainium or it would get lost. But then, maybe uranium is not the only thing that's depleted around here.

I'd bet that Graham cringes at the thought that any of his small boats might need ballast. All non-moveable weight is the bane of performance in a small sailboat. That is, providing the operator is in reasonable health. If there is some handicap, some judicously placed ballast might be a reasonable addition.

[Rob Blackburn]

Look you blokes... 2 cartons of beer, a large fibreglass ice box chock a block, a wife, her clothes, a couple of kids, a tent... some food... Forget lead in the board... all that is missing is the venue....

Rob

[capt jake]

2 cartons of beer

Only 2 cases?? LOL Besides, it goes away too fast! Of course it is only moved to a new location. Then you have the disposal issues. :shock:

[Ken_Potts]

Oh and here we go again - Now we're back to water ballast

[Gordy Hill]

I think you guys have missed something here. I've sailed a Sea Pearl and they're wonderful boats. They're long and thin and glide through the water nicely. They're also heavy compared to a Core Sound. As a general rule, heavy is bad. Adding weight to keep the sticks pointing up is kinda like carrying sandbags in your car to make it ride better. It may work, but there's a price to pay. I could get much more righting moment in my CS17 just by placing my ample self on the windward seat. Sitting on the rail would put me in another dimension.

The most amazing thing about the Core Sounds is their incredible flexibility. They can sail well in very skinny water or off-shore swells. They can ghost along in a mere wisp of a breeze or power along in a gale. They can do this empty or with an impressive load.

The Sea Pearl, fine boat that it is, just doesn't have the same range of performance. They're a handful going downwind in a heavy breeze and if conditions require filling part of the boat with water, maybe it'd be better just staying on shore.

.Since the Core Sound has so much more beam, "talking balast" is far more effective than it would be in a narrower boat such as the Sea Pearl.

[Tom Lathrop]

I thought I said that Gordy, but you said it better and probably more understandable.

[Kidd]

All this talk about a nuclear Core Sound! What's the point of uranium if ya aint got a reactor? :?