Derek's Ballast Calculator

[cyclone]

Derek has been working on this opus for quite a while, it is darned impressive. I haven't sat down and figured out what CG my boat has yet, but I will. Enjoy!

http://www.epicmarine.com/docs/Epic Ballast Calculator.xls

[toyotafreak]

Thanks Pete! Guys, it's 2.8 megs, so better 'right-click' and 'save as'.

Have fun!

[Bitzco]

So Derek, do you have a job? I wish I had the time to come up with this stuff.

[toyotafreak]

That took most of my weekend, and I already had a good headstart. Kinda just started to get it out half-a$$ed but then realized I wanted the free world to be able to use it. Had to make it nice. I'm so stoked on this thing. The maintenance presentation is a 'got to', like a 'duty', but this ballast deal is just friggin cool and fun and something you don't usually run across in our circles.

Back when I was designing r/c airplanes, and even recently when looking at speaker enclosures, etc., I always benefitted from people who took the time to make good tools available for us regular guys. My turn to offer up something that hopefully many people will use to experiment with their setup.

[phenom_1819]

Dude, you friggin' rule.  But you know that.  I'm really glad you don't captain a Malibu.   

[toyotafreak]

You d-drive guys......

The CG I've given as the 'empty boat CG' is right where the gray line goes across the boat. You can see that the line goes right over the front of the engine box. This may or may not be correct; it was just a guess from a non-d-drive guy. My reasoning for placing it so far forward (although still aft of center) was that there seems to be a lot of structure up front (helm area, etc.) and engine is real close to midships.

To you guys, it might just be good to keep in mind that the actual CG (before and after weighting) is not important - it's the delta between empty and weighted that counts. In that spirit, you might try moving the number (leave the line for now) and/or weight of the empty CG and then try some before and after ballast comparisons. Maybe try the same ballasted scenario and record the total CG, then change the empty CG and look at how much different the total CG is/becomes.

I'm totally open to input of all sort on this.

In a while, I'm gonna pull the trigger on Wakeworld, so they can check it out and similarly-anal peeps can adapt the spreadsheet to their boats.



Last thing...I took the time to make sure this thing prints well. The instructions print in three pages, the boat pages print six boats per page, and the rest just don't matter so much. You can 'print entire workbook' or go to your tab and 'print active sheet'.


Cal: 2Pac  - Thugz Mansion and Who Do You Believe In?      Dang.

[phenom_1819]

What? (I'm not a 2-pack fan... it's all about Notorious BIG for me)

I can only look at the basic version of your calculator, I'm guessing you have some images that correspond with the spreadsheet? I don't have excel, so had to open it with the cheezy Microsoft Works version. 

Anyway, I think you probably guessed center of gravity correctly. My guess is the center is right at the front of the engine, at the serpentine belt.

[toyotafreak]

Guys, I've been patiently waiting for feedback (good and bad) for a few days. Will be out of town this weekend, returning Sunday night, then leaving again 'till Wednesday night. PLEASE take a little time to check it out, see if the instructions make sense, see if after reading the instructions, the boat pages make sense. Do you find more value in seeing the size relationship between the sacs and your boat or the actual CG calculations?May be minor, but are there any caluclators you'd like added to the last page? Any sacs to the sac page?

Did I miss anything BIG, like "....WTF, dude....when you ballast, an aft-CG and a forward-CG are only like 2" apart."

Any real-world knowledge you guys can apply to this sheet that I've missed?


Not looking for 'good-on-ya's', not being overly needy or nothin, but is it cool? Is it something you wish you had when you were getting ready to buy sacs or build a system? Something that makes you want to start tweaking your current setup? Something that you will use once you decide to upgrade your current setup?


Finally, is there any chance that as-is (with the other boats added), the mainstream wake dudes could actually USE this sheet without getting bgged down in "dude, the bag changes size when I move it."




Anyhoo, thanks for being unwitting beta-testers.



And you are really my target audience, despite the talk of releasing to the general public. I'm loyal to you all (us) like you just can't know. I so agree that without the work that Pete has done, the input that all the original guys gave, the work of Les and the interest form all the new guys...my awesome S22 might not be one of the apples in my eyes ;-)

[2000epic]

Well no ya done it, a whole winter's worth of ballast research upstaged with a few clicks of the mouse.  Hope you're proud of yourself.  Now that I have my sacs figured out, I need a system to fill them.  Right now I'm plopping an 1100gph over the side into the lake and that just won't do.  What are some plumbing options with the Epic and what kind of pumps/valves/check valves are peeps using?

[toyotafreak]

Pete's got the most-covered option covered in the How-To pages. All my work to -date has been academic. Most of us drop the pumps oveboard. Not such a bad way to go.

You're pobly in the same boat as me. I'd plumb a locker sack with two Rule 1100s and a Flow-Rite valve (look around in the photo gallery). Would plan on putting a 750-pound Big Bump in the trunk or a 1000-lb Fluid Concepts sack or get a monster custom made to fill the full height, width and depth of the trunk - might be 1300 pounds. Might also leave some plumbing available for a temporary fill of a Fat Seat or Side Sacs.

As far as the bow goes.....that's a good one. You've got to give up the cubby or the bow seating or both. Or you carry lead with you. When you get it figured out, let us know. In all likelihood, I'll probably plumb the aft sac(s) in a sweet way but stick to the manual-fill up front.

[blindside]

Sorry man, i haven't even had a chance to use it yet.

[cyclone]

Derek,
I've settled on the locker sack in the trunk and full sack in the walk through. It is the best compromise for me. I'm thinking of putting tube sacks up under the front seats, but I'm not sure if it would be enough weight to hassle with it. Plus, the consequences for overfilling those sacks is broken fiberglass. Even with an unrestricted overflow tube, the sacks will still expand enough to break stuff.

[toyotafreak]

You're close enough to the water, couldn't you afford to carry lead sacks up front? Not really lead, but the sacks I got from Troy Lindstrom (Pop Products) are 40-pound plastic sacks full of metal stamping leftovers, slid inside a nice fabric sack with tough nylon webbing. Anyway, if you play around a litle you can see that it doesn't take a ton of weight when you get it WAY forward. Check out the difference in arm between a walkway sack (where its CG's at) and the arm of the three bags placed directly under the little bow cushion and x number working their way back from there.

He chose 40 pounds after 'a lot of trrial and error' in that he felt that size was just the most manageable. If you are interested, I'm sure he'd be willing to sell just the sack and let you locally-procure your weight. Recourceful guy like Pete should have no problem coming up with some high quality metal ballast.

On a related note, there's a dude in Cent Cal that is placing real life lead shot into fat sac material and then sealing it shut. That to me is the absoluter pimpest. Shot isn't abrasive, can't snag, and is super dense. The sac material is strong and they do seal really nice. Lead takes up MUCH less space than steel. Maybe with lead you could get almost twice the weight in the same space.


And Pete, what were the sheet's results when you recreated what you've been running with for some time? Fat Seat partially filled and what else?

[cyclone]

I confess I haven't sat down and entered my info yet. The wake changes so much based on how many people are in the boat that I usually just reposition kids until there's no whitewash and bow rise is minimized. There's always at least one kid that wants to sit in front.

I would like to get some of those bags, my pal is interested too. Like you suggest, it's probably cheaper to get weight on my side of the US rather than ship it. Do you have contact info for those Pop Product bags?

[highflyn]

Derek
After taking a long and hard look at the avalible space in my SX, I relized what I need.
Three 105-110 "SACKS" 5'2" to 5'6" long, no cover is nessecery. I would prefere they be portable  so i could move them to where the weight is needed and because there may be times when a friend needs to borrow my "SACKS". I did not see any of these in your Calculator. Would this be a custom job?