24Ve maximum ballast writeup...

[Timmy!]

I keep coming back in here to check that wave out to see if it looks smaller after seeing it a few times...nope, still huge!

[IDBoating]

Great job WA!That is one serious wave.

This is my first wakeboat. Don't they ALL put out waves like this one?

{grin}

[IDBoating]

Next installment: Dual-mode fat sacs...

I've written here and there about "mode 1" and "mode 2" and "arms deployed" and such, so I figured I should clarify what I mean by that in this next short installment.

As with most Enzo-style fat sacs, our full-custom Fly High sacs have main bodies that fill the rear lockers and "arms" that extend forward into the underseat storage. Here's a repeat shot for convenience:



Under normal conditions, as you fill the sacs the shorter-height arms fill up before the taller, locker sections top out. This means you are adding weight toward the front of the boat before you get the maximum sac ballast weight at the rear of the boat. That's great when what you need is absolute maximum ballast, as we often do when our three-person family is out surfing without any other friends or family.

But what about when you have a bunch of friends (read: human ballast) along? A few adults can represent 600-800 pounds all by themselves, and when they sit on the seats that weight is already toward the front of the boat. It's also well above the bottom of the hull. That conflicts with the fact that the 24 foot hulls want their ballast concentrated down low at the transom; that's how you get those giant, sweet waves shown in this thread and on RagBoy's 24Ve shots.

Why not just fill the sac completely even with human ballast onboard? Because these fat sacs are HUGE. When designing this system and calculating how heavy those fat sacs would be, I worried that with enough passengers we might have TOO much ballast. And that turned out to be the case. We experimented with a full boat of people and filling a sac to capacity and we were well over the top of the rub rail long before we would have had the sac full.

Moreoever, if you simply fill an Enzo-style sac in the traditional way when you already have lots of human ballast onboard, you will be concentrating the ballast well forward of the transom. This changes the attitude of the boat in the water, and hence the wave shape.

What you'd rather have is a way to keep all of your water ballast down deep at the transom in all conditions. Basically, you want to let the human ballast take the place of the fat sac's arm while still filling the locker space to its maximum solidly low and back against the transom.

Here's a view of the starboard fat sac space, looking aft:



(In this photo, the fat sac has been disconnected and pushed back for access reasons.)

This photo is taken from the front of the "arm" space under the seat. This is the ballast volume the humans replace. But you want to keep the locker space (in the distance, toward the transom) completely full. How to do that when the locker space is so much taller than the underseat space?

With these:



These are two pieces of 1/2 inch Starboard cut to match the inside profiles of the fronts of the lockers, all the way down to the hull. Some edges are slightly reshaped to permit easy installation and removal, but essentially they present a big flat surface to the front of the fat sacs.

Looking in the other direction in the starboard locker, from the transom toward the bow:



...you can see that the sloped surface of the inner hull gives way to the raised and level floor of the underseat storage. That, combined with the seatback above it, provides a nice mounting surface against which the associated "sac wall" can rest. The fuel filler hoses on each side hold the walls in place; the walls just slip in between the hose and the seatback and no hardware is required.

In practice, when a large crowd will be onboard the arm is simply rolled up and the wall is installed against the two flat surfaces as mentioned. The volume consumed by the unused arm is forward away from the transom, again keeping the ballast concentrated low and aft. The locker portion of the fat sac fills to the top without undesired weight in the arm shifting the ballast volume forward.

The walls can be swapped in and out in a few seconds without tools when the sacs are empty. If this switch is made while out on the water, the walls can be stored in the lockers themselves by simply setting them on one side or the other of the fat sac before filling. The pressure of the then-filled sac holds it out of the way.

As an extra benefit, when the walls are installed you regain all of the underseat storage space. You're most likely to need extra space when you have lots of passengers anyway, so this works out quite nicely.

If I were doing this again, I have one design improvement in this area: I'd make the locker sacs and the arm sacs completely separate (four sacs instead of two), with matching fittings that line up when the sacs are installed and filled. Then I'd connect the sacs using a couple of short lengths of hose so that water could flow into the arm during filling and back out during draining. When not needed, the arm could be blocked off by a valve in the hose or by disconnecting the hose from the locker sac and closing it with a Fly High plug. Ewok, another Spokane user on this site, brilliantly pointed out that this approach would also reduce sloshing as the boat accelerates and decelerates, much as baffles do in fuel tanks. While this would be a nice improvement, my existing fat sacs were darned expensive and I'm not going to replace them until it's absolutely necessary!

Coming soon: Drain/vent systems and console wiring. Thanks!

[Timmy!]

Hey WA, think you can compete?
http://slayshtank.com/2012/03/wakesurfing_biggest-wave/

[IDBoating]

Maybe. I'm in it for the enjoyment with family and friends, not to win a "mine is bigger than yours" contest.

But...

I still could go a bit farther. Even with my ballast sac fully loaded my rubrail isn't touching the water. The photos here were taken with almost no passenger load. I wonder what my wave would look like with a few buddies onboard. I'm supposed to have some beefy friends staying over during the first week of August. Hmmm....

EDIT: OK, I had to stand up for the Tige brand. I sent them a photo. We'll see. (If Tige wants to guarantee the win, they could always provide me with a Z3 and let me ultra-ballast it. I hereby publicly offer my services toward that end. )

[Wakeman22]

Maybe. I'm in it for the enjoyment with family and friends, not to win a "mine is bigger than yours" contest.

But...

I still could go a bit farther. Even with my ballast sac fully loaded my rubrail isn't touching the water. The photos here were taken with almost no passenger load. I wonder what my wave would look like with a few buddies onboard. I'm supposed to have some beefy friends staying over during the first week of August. Hmmm....

EDIT: OK, I had to stand up for the Tige brand. I sent them a photo. We'll see. (If Tige wants to guarantee the win, they could always provide me with a Z3 and let me ultra-ballast it. I hereby publicly offer my services toward that end. )

My vote is for that.

[Timmy!]

I knew you couldn't resist!

[duffymahoney]

Once I cut my chines, install the floating wedge I think the award will be mine!

[IDBoating]

I knew you couldn't resist!

Guilty... but in a good way!

[IDBoating]

Once I cut my chines, install the floating wedge I think the award will be mine!

Maybe not if Tige provides me with a Z3 to ultra-ballast.

[duffymahoney]

My lockers are bigger then the z3s by a long shot. Plus my transom sac and lead. The z3 has no chance. The rest of the hulls are similar. The award will be mine. In my mind stanley wheelhouses 247 is the best wave out.

[Timmy!]

It's not purely ballast that creates the wave, the hull shape has a lot to do with it as well.

[IDBoating]

It's not purely ballast that creates the wave, the hull shape has a lot to do with it as well.

Agreed, which is why I think the combination of ultra-ballast and the Z3's surf-tuned hull would be a natural winner.

Back here on my humble 24Ve, though, I do have some experiments to run this season with waveshaping. I've got the size, so it's time to start perfecting the shape. Mine don't involve reworking my hull, though... something less permanent and faster to dial in.

I will happily postpone my research on the 24Ve's hull, though, if Tige wants me to use a Z3 to trounce the other brands in this contest. We know the Z3 was intentionally optimized for surfing - it's time to claim the title for all to see. That hull plus ultra-ballast... the results could be mind-blowing (and embarrasing to the other boat brands!). I'm willing if they are.

[duffymahoney]

Lets hope chine removal = better wave I would love to surf a custom sac'd out z3.

[Timmy!]

Lets hope chine removal = better wave I would love to surf a custom sac'd out z3.

You'll have your chance in May at the wakesurf open!