Moomba Mojo 2021 Revised Ballast Placement

[Hayden]

I've fully plumbed in the additonal bow bags that were previously being filled/drained with a Tsnami pump. Definitely pushing the nameplate maximum of 6500 lbs at this point! Here's all my schematics and a video of how I routed, rewired and got it all setup.

[cucv]

Thanks for posting this, great info! What is your fill time with this extra ballast?

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[Schlanseay]

Did you relocate your sensor?


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[Hayden]

What is your fill time with this extra ballast?

I didn't have enough time to get exact numbers on the front bag setup but it is very close to the rears now. I will post up this info the next time I go out and let you know.

Did you relocate your sensor?

I moved the front water sensor from the rear vent line to the front vent line to eliminate nuissance tripping.

[cucv]

@Hayden tell us about your prop with this setup and engine rpm surfing and cruising.

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[Hayden]

@Hayden tell us about your prop with this setup and engine rpm surfing and cruising.

I had an ACME 2775 the first year (2021), 15x12.5x0.75", but fully loaded it still really struggled at my elevation, 10deg pitch, and had very high rpm's (4800-5000). If you look back at my post history, I was asking about it that year, wondering if I was going too high. I called Indmar and they said it was fine upto 5200 but many of the veteran members on this forum advised against running like that year over year. That's one of the problems with going down in pitch is that you go up in RPM's.

Late in 2021, I called ACME and asked them what they had heard for boats pulling over 6k of ballast and I can't remember who I talked to but they recommended the 3407 (15.5x13x0.150") for all the Moomba +6k ballast, 2021's. They said the 3407 was performing the best for that weight/elevation class with both the Mojo and Makai.

For 2022, it was a game changer in terms of lowering rpm and didn't struggle at all with the load. I ran it flat out, unballasted with the 3407, two weeks ago and was at 38mph. When I ran it last year at 10deg pitch, fully ballasted, 11mph, I would be around 4300-4500 rpm depending on headwind or the amount of extra people on board. At 9.5deg pitch, same conditions, it would go down to 4100-4300, at 9deg pitch, same conditions, it would go down to 4000 or so.

I think the only time we've gone below 9deg pitch was a friend who had skinny 110 lbs kid wanting a flat wave for skim tricks.

Just remember all the things to consider: pitch-of-boat/density altitide/prop diamter/prop pitch/prop cup/total weight/headwind


....not that you should be surfing with headwind but the season is short and there are only so many weekends in the summer!

[Hayden]

Thanks for posting this, great info! What is your fill time with this extra ballast?

11min to get it all the way full with G6 twin pumps. The front subfloor + the two bow bags take the longest. I haven't changed my impellers since I bought it, so that could be a thing as well.

[cucv]

@Hayden thanks for following up. I watched all your Ballast videos and was doing the math and figured it at 11 minutes, sounds like your impellers are doing just fine. Are there other reasonable areas to add water Ballast or have you maxed it out? How long did it take to get the custom rear bags?

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[Hayden]

@Hayden thanks for following up. I watched all your Ballast videos and was doing the math and figured it at 11 minutes, sounds like your impellers are doing just fine. Are there other reasonable areas to add water Ballast or have you maxed it out? How long did it take to get the custom rear bags?

You could maybe get another 200 lbs in the very tip of the bow with some sort of triangle bag piggy backed off the bow bags? Would be difficult to plumb in though, no room to work. If you didn't care about symetry you could put at least 400 lbs next to the amp under the passenger side compartment but that's using all of the space and getting hose/fittings/leaky water near the amp/charger/etc. Gotta draw a line somewhere :P

Took about 2-3 weeks to get Fatsac to make and deliver the 1800 lbs rear bags across the border.