Concrete ballast put into a 260 ballast tank

[Crazy Dave Condon]

I was asked a question if either in a solid or liquid state, would concrete be viable in a 260 water ballast tank. If it is liquid what would it do to the environment when you open the ballast or empty the ballast. Concerns are several. What if any would that concrete in a wet state due to caustic substances might harm the tank itself. Secondly, the added weight could collapse the bunk supports and or indent the hull damaging it. The added weight might be overloading the tires not to mention the bearings and racers too. I can think of other issues as well .
The original design of the 260 incorporated water ballast and the design of the boat was designed around that principal, not anything else. Therefore, I will stay with my responses for a water ballast boat only.

 

[rgranger]

That is crazy for all of the reasons you mentioned plus some more but.... concrete would not stay liquid. Concrete will set underwater so.... you would be stuck with it.

 

[cb32863]

Concrete also generates heat as it sets. Not sure how well the tank would hold up. But, yes, a crazy idea for sure.

 

[rgranger]

Dave: I don't know the backstory for this post but it occurs to me that if the original question was "how can I add ballast weight to an H260".... I can think of a few safer ways.

The first is to add a lot of a highly soluble salt. In addition to the added weight, the polarized nature of ions increase the density of the water present so essentially more water gets pulled into the tank. Ammonium Nitrate comes to mind. It would also have the added benefit on a hot summer day of being very cold. Ammonium Nitrate is what is used in instant cold packs. You could probably dissolve 50 to 100 pounds in the ballast tank and the added density from the polarization and the cold might up your ballast by nearly 200+ pounds.

The down side of something like that is that it would be an ecological disaster when you opened up your tank. Ammonium nitrate is fertilizer and dumping that into an ecosystem would be "criminal" in my mind. There are other salts that are more ecologically friendly but any salt in a fresh water system would be problematic.

You could also try sugar. It would not have as many negative ecological effects as ammonium nitrate but I can imagine a lot of problems with sugar none the less. "Fermentation! Fungal growth etc.

Anyway! Strange post.

A better solution would be to invite some rail meat to the party and go sailing with some friends.

 

[Bill Roosa]

Well concrete is 3.2 times as heavy as water so you would not want to fill the tank with it. If you use the correct amount (ie the weight of the equivalent full tank of water) it would actually lower the CG and make the boat more stiff. weight is weight so as long as you leave it in the water there should be no problem. When you pull the boat is when I'd get worried. bulkhead/hull over stressed just like if you left the drain plug attached. The trailer will not be happy either.

 

[Jackdaw]

Concrete does not dry. It cures. The water does not go anywhere, it converted in the curing. Fun. Plus curing concrete is an exothermic reaction. Gets warm. Hopefully not too hat to melt/soften any boat parts.

 

[Bill Roosa]

If all you need if more ballast hire some crew.

 

[David in Sandusky]

This comes under the general category of:

"I bought this boat, but I don't like the design...!"

The best answer is almost always, "Sell the boat, and buy a design that fits your desires."

Bastardizing a design is always the mother of unintended consequences!

 

[Kermit]

I've been threatened with concrete overshoes.

 

[Crazy Dave Condon]

I was asked why this came up. Sometimes it could create legal issues but as long as questions are asked, then no problem. As for a design with water ballast and concrete is added, I heard put training wheels underneath or use the boat as a planter

 

[flynhi4u]

I've been threatened with concrete overshoes.

SHOCKING!!!

Sam

 

[All U Get]

So many options for ballast why not just use sandbags? Or rum?

All U Get

 

[Justin_NSA]

I've been threatened with concrete overshoes.

Fish mafia

 

[rgranger]

Why is it always "Carl"?

 

[Justin_NSA]

Why is it always "Carl"?

A Carl probably bullied Gary when he was young

 

[rgranger]

Got me wondering so .... I googled it... From http://conorlastowka.com/2012/01/far-side-names/

No explanation as to why but this is what I found. And yes! Someone spent considerable time compiling this list. (Get a life)

The top male name for a Far Side character is…Bob! This was not even close. Bob appeared in 54 Far Side cartoons, blowing away the next closest name, Frank, with 38 appearances. Third place, Carl, started out strong, dominating the first year or so of the comic. But while the early years were full of Carl’s, it just did not have the staying power, and only appeared 23 times. Here is the full top ten list of male names and the number of comics they appeared in:

Bob 54
Frank 38
Carl 23
Billy 21
Ernie 21
Harold 18
Henry 17
Larry 17
Al 16
Sidney 16

 

[flynhi4u]

Got me wondering so .... I googled it... From http://conorlastowka.com/2012/01/far-side-names/

No explanation as to why but this is what I found. And yes! Someone spent considerable time compiling this list. (Get a life)

The top male name for a Far Side character is…Bob! This was not even close. Bob appeared in 54 Far Side cartoons, blowing away the next closest name, Frank, with 38 appearances. Third place, Carl, started out strong, dominating the first year or so of the comic. But while the early years were full of Carl’s, it just did not have the staying power, and only appeared 23 times. Here is the full top ten list of male names and the number of comics they appeared in:

Bob 54
Frank 38
Carl 23
Billy 21
Ernie 21
Harold 18
Henry 17
Larry 17
Al 16
Sidney 16

What?? No Sam or Kermit...

 

[Scott T-Bird]

Concrete weighs about 150 pcf and water weighs 62.4 pcf. I read one source that said the water ballast of a 260 is 1,000 pounds. It was difficult to find exact information, either in weight of water or gallons of water ballast. Sailboat data indicated 2,000 pounds ballast, but another source indicated that the centerboard contributes 1,000 pounds. Anyway, 1,000 pounds is 16 cubic feet or 120 gallons. That sounds reasonable. The weight of cured concrete is only 87.6 pcf more than the weight of the water in the ballast tank, so the total additional weight of ballast would be 1,400 pounds. That doesn't sound too radical when it is evenly distributed at the bottom of the hull. What's the floor area of the ballast tank? If it is just 0.5' deep on average the floor area might be 32 sf or 4' by 8'. Does that sound right? The added weight might be about 44 psf (75 psf vs 31 psf). The difference is about the live load for the floor of a residence (people and furniture). That could be significant for the stress of the hull - I'm afraid I don't know about that intuitively. Of course, if the water ballast is really 2,000 pound (240 gallons - really?) all my calculations would be doubled and I would begin to see why it would be a totally bad idea.

It doesn't sound that crazy to me. The heat of hydration in concrete can be significant if the mass is greater than 36" thick, but this wouldn't be the case. The damage from this heat is typically described for the concrete, not the formwork. If the concrete cracks, it really doesn't matter in this case. Unless it was poured on a really hot day, I doubt the heat would be significant. If the concrete was poured and the boat was placed in the water while the concrete cures for a day, there would be no problem. I can't see why there would be any damaging chemical reaction between the fiberglass ballast tank and concrete.
The additional weight on the trailer would be 2,400 pounds (total weight of the concrete, assuming water is normally removed during towing). That would be a significant weight increase, but I would guess that the trailer could be modified to handle it.

 

[rgranger]

Concrete weighs about 150 pcf and water weighs 62.4 pcf. I read one source that said the water ballast of a 260 is 1,000 pounds. It was difficult to find exact information, either in weight of water or gallons of water ballast. Sailboat data indicated 2,000 pounds ballast, but another source indicated that the centerboard contributes 1,000 pounds. Anyway, 1,000 pounds is 16 cubic feet or 120 gallons. That sounds reasonable. The weight of cured concrete is only 87.6 pcf more than the weight of the water in the ballast tank, so the total additional weight of ballast would be 1,400 pounds. That doesn't sound too radical when it is evenly distributed at the bottom of the hull. What's the floor area of the ballast tank? If it is just 0.5' deep on average the floor area might be 32 sf or 4' by 8'. Does that sound right? The added weight might be about 44 psf. That is about the live load for the floor of a residence (people and furniture). That could be significant for the stress of the hull - I'm afraid I don't know about that intuitively. Of course, if the water ballast is really 2,000 pound (240 gallons - really?) all my calculations would be doubled and I would begin to see why it would be a totally bad idea.

It doesn't sound that crazy to me. The heat of hydration in concrete can be significant if the mass is greater than 36" thick, but this wouldn't be the case. The damage from this heat is typically described for the concrete, not the formwork. If the concrete cracks, it really doesn't matter in this case. Unless it was poured on a really hot day, I doubt the heat would be significant. If the concrete was poured and the boat was placed in the water while the concrete cures for a day, there would be no problem. I can't see why there would be any damaging chemical reaction between the fiberglass ballast tank and concrete.
The additional weight on the trailer would be 2,400 pounds (total weight of the concrete, assuming water is normally removed during towing). That would be a significant weight increase, but I would guess that the trailer could be modified to handle it.

Interesting thought experiment Scott.

I thought about this some last night and an additional unknown is what the bottom of the ballast tank looks like and how would the concrete sit in comparison. I assumed the modification would not include filling the entire tank but just a partial fill. And if that is the case, how would you keep the concrete secure? What happens if it starts to move around during a knock down? Seems like a big risk to take on your boat unless you just have $$ to burn and like tinkering with stuff.

 

[Scott T-Bird]

I think I would fill the ballast tank just for that reason. Not knowing how the boat is constructed, I wonder if the tank is a separate structure or if the hull is actually the bottom of the tank. I think it would work best if the hull were the bottom of the tank, otherwise, an independent tank is probably not secured well enough for an additional 1,400 pounds.