Question about MB ballast system.
 

With that gate set up for the ballast tanks, is it true you cannot empty the tanks while in the water, you have to put the boat on a lift or trailer it out?

While moving forward the tanks will empty on the water, but you have to be moving forward with enough force to get the transom out of the water. It's actually really a sweet setup.

I've thought about this setup quite a bit. Is it just one big tank under the hull? Or maybe one per side. It looks like to me your options on ballast would be empty or full. Anything less than full and while underway it would all run to the back and slosh around right?

I found this on the MB website in the FAQ section"Can I empty my ballast tanks in the water while moving forward in forward gear?
Only on 2005 models, they have a new dump system that allows water to be discharged at any speed. On all other models the forward motion loads the pump and will damage the impellers or blow the ballast pump's fuse."

It doesnt make much sense to me, maybe they mean 05 and up.

Any MB owners?

They have 2 hard tanks. One on each side, under the floor. You can fill halfway and it would slosh, but that wouldn't hurt anything. Most wakeboats with hard tanks half full would slosh. I believe the older MB boats use the same through hull to empty and fill via a impellar pump. So you could still empty underway but as they have stated it could hurt the impellar. But my last boat had a similar system and it never hurt it. Their new system 2005- current, uses valves and gravity etc... to fill. Simple and fast and easy. Best designed ballast system on the market in my mind. You can still add sacs, there is still plenty of room for an enzo sac on each side if you wanted. My neighbor has a sweet new tomcat. The boat is freaking huge and sits so far out of the water.

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The 05 - mid 08s have the impeller based pump systems and according to my former dealer could be operated while underway. the later 08s til current have the gate valves. The 21 foot boats have 1800 lbs of ballast split between 2 tanks. The F23 Tomcat has 2400 lbs in 3 tanks (if memory serves me correctly) I have no regrets about buy my MB.

So than you can empty on the run?
Is there a guage on the dash that tells you the level?

Yes, you can empty on the run. There is a gauge that you can toggle b/n left tank and right tank. The 21' boats have 2 900lb tanks that go from the cockpit to the stern of the boat.

Mario-

They don't slosh, there are baffles every couple of feet. The new system is very simple to use and to trim.

here's a pic of the tanks of my 2010 F21 well being built. you can run the 1/2 full, and some time i have had to let a little out to adjust. I'm loving my boat!!!!!

I made this video last year. It might answer some of the questions posted here. At the very least it shows how the ballast gauge works.

http://www.youtube.com/watch?v=v651LFNUPCk