Heavily Weighted (6500 lbs) Ballast - Engine Wear & Additional Maintenance

[SONIC]

The prop was cheap and available, so we grabbed it rather than waiting for something to be shipped across the border. Our water level is already dropping and with the heat we had at the end of June, many are worried the season won't go far into August. It was the quickest solution but I agree, not the most efficient.

Check those vids I posted, they show where all the other weight is going (2x 400 midships, 2x 150 bow, 500 leadwake).

Gotcha, awesome project either way that wave is going to be a monster.
I'd experiment with less bowrise as well, wake9 didn't have nearly that much weight in the boat so you may not need 10 degrees.
Different hull but mine is about the same from 8.7-10 with very little noticeable difference

[sleek98]

Gotcha, awesome project either way that wave is going to be a monster.
I'd experiment with less bowrise as well, wake9 didn't have nearly that much weight in the boat so you may not need 10 degrees.
Different hull but mine is about the same from 8.7-10 with very little noticeable difference

He has quite a bit of weight, but it was more human weight. In his videos you can see he has 5-6 people in the boat plus his 1,000# of lead. I would say he is near 2k pounds all in.

Hayden and myself usually only have 1 or 2 people with us at a time (last time out it was just my wife and I). So we took the measurements to add in the rear bags as well as midship bags to offset not having many or any people in the boat. I run less than Hayden with only 1,600# of added ballast plus wife and kids of 250#. The elevation and the extra 800# must really be hurting him, I run the 15.5x16.5 prop and only had one time I couldn't get up to surf speed, that was when I had an extra 600# of people over normal (I was pushing the 2,500# max). I am at 850' of elevation though. I typically run 3,700 rpms when at surf speed with 1,850# of people/gear/lead/bags.

I would like to get that down to 3,200 if I can. But I am not sure I can even going to a 16" prop. I need to measure putting a 16" prop on the boat to see how much room it really will have, and likely will put a piece of SS as a guard on there. I am leaning towards the 16x15 prop for me.

[mjb929rr]

I don’t think changing the prop is going to help. I have an sl450. 900 lbs lead and no ballast is what the kids surf at. Rpms are 2850 @11.2. With ballast full that goes up to 41-4200rpms. Same prop. More weight is going to require more rpms. This is a 16x13.9 prop 1.76 ratio

[sleek98]

I don’t think changing the prop is going to help. I have an sl450. 900 lbs lead and no ballast is what the kids surf at. Rpms are 2850 @11.2. With ballast full that goes up to 41-4200rpms. Same prop. More weight is going to require more rpms. This is a 16x13.9 prop 1.76 ratio

I think your right with it making it higher. I was thinking with the bigger diameter it would drop it some, but its more dependent on the pitch.

You are sitting at 10k pounds fully loaded no people, 5,600 + 3500 + 900. I am sitting at 10,400 with no people. Maybe I would be better off just leaving my prop as is and get rid of lead or dont fill my extra midship bags if I get an additional 4-5 people in the boat. The wave I have with just my wife in the boat is amazing so I dont need any additional weight, but I can easily take weight out by not filling full or chucking some lead on the dock.

[mjb929rr]

I feel like added weight is great to a certain extent. A lot of times it’s just the wife and I and 2 small children. That is why we run the lead. We have surfed with 16 people before and 12 were adults. At this weight the lead isn’t needed and almost makes the wave harder to dial as the extra weight really makes the 450 struggle. We find our best wave is with 6-8 people and the lead.

[Hayden]

Finished up some telephone conversations with both Skiers and Indmar on this: bottom line is that so long as you remain as per the nameplate rating of the boat, which in my case for the 2021 Mojo is 4000+2500 = 6500 lbs of people/gear/water/leadwake, the engine is tested and capable of handling the load, Indmar confirmed that 5000 rpm was within tolerances..albeit right at the edge.

I'm going to try and mess around more with the bringing the pitch and maybe speed down to lose some rpm's but I've never had the wave as long or as pushy as I have with where it's currently weighted. You get addicted to having that much wave to work with.

[sleek98]

I'm going to try and mess around more with the bringing the pitch and maybe speed down to lose some rpm's but I've never had the wave as long or as pushy as I have with where it's currently weighted. You get addicted to having that much wave to work with.

Yep right at 10* with around 6k pounds of ballast you can surf back in another zip code. Easy 15' back off the boat and still able to recover. At 10.5* I couldnt stay off the back of the boat when hammering on the brake 100% of the time.

[Holdmybeer]

Makes sense now why you at 5k rpms. Pitch at 10* is a lot of drag with tabs and that much weight. I run 9* with a 2015 hull. I bet the surf wake is awesome with your setup, but like Sonic said, long term I would be worried about engine wear after warranty.

[Bmac]

Sorry I don’t want to hijack this thread but you all have me questioning myself. If I have my cruise on my boat will not go above 4,000 RPMs. There are often times I just need to rev to 4200 to get up to speed but my boat won’t do it. Am I up in the night? I just figured it was a safety feature.


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[Hayden]

Just curious if you use cruise while surfing? If I have my cruise on I can’t get above 4,000 RPMs. I am assuming that it is built in that way to protect the motor from running any higher for long periods of time. For reference I have a 2020 max with a 400 at 5,000 ft. I have 5500lbs of ballast and only struggle getting to speed when surfing port side. 15.5x14 prop.

This sounds like you're hitting the limit of engine/elevation/ballast/propeller, no? There shouldn't be an rpm limiter at 4000 rpm.