Advertised ballast weight vs Actual Weight

[topherbd16]

Anyone actually measured the mass of their ballast bags to confirm they weigh the advertised weight when full of H2O? Weighing these sounds challenging, no doubt.

But I ask because I just bought a Sumo bag advertised as 1000 lb., Dimensions are 50" x 22" x 22". 14.0 cubic feet x density of water 62.4 lb/ft cubed = 874 lbs.
I know the bag doesn't weigh 126 lbs

Is this because the bag expands and is actually not square, but slightly rounded, advertisers rounding or some combination?

Maybe they used a more dense water when testing... mercury mixed in.... lol

I'm putting this on the transom/upper deck of my 212X and going to make custom 4" nylon straps to hold it in place, if after test runs I feel like this can move upon acceleration. May add a 400~800 lb. bag on the lower swim deck too... tbd. Need to test out this 1000 lb. bag first.
Need to figure out what I'm going to strap the straps to though... lol... I'd like some eye hooks, cleats, etc. on the top of the transom seats, opposed to having rope go sideways to the wake tower. Hopefully the bag just stays... whether it's 874 lbs or 1000 lbs.

 

[anmut]

I believe the manufactures state 1000lbs vs the dim weight is because a properly inflated bag (according to Fly High Fat Sac at least) bulges beyond it's dimensions. Probably a better way to get an accurate look at them is to fill them on a commercial scale.

 

[topherbd16]

Makes sense to me. I may try a water displacement test in a hot tub... or find a commercial scale, as you say. This information is not needed, just purely for my nerdiness ?‍?. There are other bags from different makers of same dims that have different weight advertised as well. I just find it interesting.

 

[Marvin willis]

I tried to use heavy ppl instead of a ballast. It didn’t work at all

 

[topherbd16]

I tried to use heavy ppl instead of a ballast. It didn’t work at all

I’ve had success with 5 adults sitting in stern area and 300 pounds of sand in canvas bags on transom deck surf side. But ballast on the rear decks will do more, pound for pound.

 

[anmut]

I’ve had success with 5 adults sitting in stern area and 300 pounds of sand in canvas bags on transom deck surf side. But ballast on the rear decks will do more, pound for pound.

Agreed - for whatever reason on the Yamaha's, pushing that deck down is super important - maybe because it forces the surf side jet under the wave more?

 

[topherbd16]

I think sinking the jets are very important. That jet wash is terrible for alll water sports, but good for fuel efficiency. The wedge knocks that jet wash down, TVWs too, wakebooster forces so much more water by the jet it cleans it up as well. But simply the further the boat is sunk the more water displaced and the more the water has to come back up meaning bigger wave. That’s why the 6 figure boats fit 4000lbs or more in ballast.

move has a lot of weight with no wakebooster. Wave was bigger full of whitewash. Wakebooster by itself and stock ballast is ok. But the pocket is tiny and not fun unless you just want to cruise in one spot. Combining a crap ton of weight To rear surf side and the booster, wedge or tvw means bigger wave. Adding more weight to front means a longer wave. I’m now figuring this all out as my wife just wants to anchor and read a book while I’m trying to sink the boat!

 

[anmut]

I’m now figuring this all out as my wife just wants to anchor and read a book while I’m trying to sink the boat!

Same. She just shakes her head as I'm pumping hundreds of gallons into the boat, looking at the wake, and taking pictures of perfect wave. I think she thinks I have a problem. She may be right.

 

[Marvin willis]

Does y’all’s boats shake a little at high rpms and 10 mph for surfing

 

[anmut]

Does y’all’s boats shake a little at high rpms and 10 mph for surfing

Not that I have ever noticed - usually with the RPMs that high the motors are screaming. Are you feeling the booster I wonder? When I'm surfing I notice the booster has a "choppy" sound to it.

 

[Marvin willis]

I’m not sure the ppl on the boat feel it but I can feel it in the throttles.

 

[topherbd16]

I’m not sure the ppl on the boat feel it but I can feel it in the throttles.

I haven’t noticed that, but will pay more attention this Sat. I was getting a heavy steering vibration when I was turning right at 20+ mph, but left and straight were smooth. I need to check that out for sure.

 

[Marvin willis]

It could be bc we’re surfing in 5-6 ft of water

 

[anmut]

It could be bc we’re surfing in 5-6 ft of water

I wouldn't even attempt that! 5-6 of water will not a good wave make. Also, with the boat sucked down that far, you're really leaving youself open to introducing something off the bottom into your pump system. 10' minimum for a wave, 20' for a fun wave.

 

[Marvin willis]

I wouldn't even attempt that! 5-6 of water will not a good wave make. Also, with the boat sucked down that far, you're really leaving youself open to introducing something off the bottom into your pump system. 10' minimum for a wave, 20' for a fun wave.

Thank you