Afternoon folks!

Another great weekend in the books! We went to Harborfest, and enjoyed friends, food, and boats; fireworks for the finale! Yesterday was set up for cleanup and rest. Surprisingly, the boat stayed pretty clean despite three young kids with food and drink, as well as guests coming onboard while we were anchored for the show... we had a full boat!

So yesterday I had the boat to myself (we overnighted the boat local to Harborfest), and got to play around some without having to worry about the kids getting banged up. Overall I had fun, but man does she porpoise! Trying to get her trimmed out is where I'm running into problems.

I have marked my indicators so that I know where neutral is with regard to trim and tab position. Neutral trim is at 5/6 mark, and tabs are on 3. These indicate a position that is on the same plane as the hull bottom.

Typically, I'll leave the drives tucked in and tabs set at 3 unless I need to get on plane quickly (I'll drop them to 9 and bring them back to 3 once going). Generally. she gets on plane without much trouble (though dropping the tabs. Keeps the bow low so I can see). Once on plane, I'll bring the trim to 2/3 and leave there because she'll start to bounce as you go up in trim. The porpoise gets so bad that the boat will leave the water (see pic below).

Is it normal to run the 311 with negative trim most of the time? I would think she'd want a little positive trim to run best. Negative trim puts the bow in the water leading to bow steering (a very unsettling feeling).

502 MPIs with CMIs, 300 hours, TRS drives with nose cones, 27P Mirages. RPM at WOT is 4700-4800 depending on load.

Should I add some weight up in the bow (the water tank is empty)?

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Additional info... I used a straight edge and blocks to verify neutral running positions on the drives and tabs, and marked the indicators to show. Unless I'm at WOT, I can never get the drives even close to neutral. Anything approaching neutral creates a bounce that at times launches the boat out of the water. The included video link shows the boat running at 43-4400 RPM; tabs up, and the drives about neutral. The props are solid hub 27P Mirages that came off my buddy's Cigarette Bullet. We know nothing about the props because they came with the boat. His boat porpoised with these props too, but not like mine. We went with 26P Bravos on his, and all was vastly improved.

It has been suggested (on the Formula Owner's forum), that moving to a Mirage Plus might be a good direction to follow because the Mirage isn't able to carry the bow well. My thinking would be to drop to a 25P Mirage Plus, and go from there. The drives are two deep for a 4-blade Bravo per many. Any thoughts from the experts? Thanks!

https://m.youtube.com/watch?v=UBOqoD...ature=youtu.be

Hydromotive 4 blades. Have you checked the drive toe in?

I've always ran 4 blades on my 292, which is very similar to your boat. In stock form the Hydromotive is hard to beat. I'm now running labbed Bravo's and like them better, but if you don't want to spend the money having them worked on, get some Hydro 25's.

As far as porpoising, mine will do the same when cruising at 3000 rpms. I need to leave it at neutral trim. Anything over 3500 and I can start to trim up. When I had my drives at stock height, I could trim all the way up to 9. Last year with -2's there was no need to go past 6.

That's the thing... I can't event get to neutral.

Thinking about pulling the Bravos off the Bullet to give that a try. We meant to do that before the start of the season, but ran out of time. Maybe these props are screwed up.

Sounds to me like your props are bad. Your boat is fastest with standard Mirages, however I like 4 blades on these hulls. You lose a touch on the top end, but you gain everywhere else.

Took the boat out this evening and here are some observations... I took a voice recording after my testing, and for the most part, below are my findings.

Fully tucked in, the indicator is at the slash between 0 and 1.

Getting on plane is no issue.

Tests conducted at 3-3200 rpm.

If I run the trim up in large bursts, I get ridiculous porpoising. The boat will porpoise so bad that she'll begin to get the drives out of the water enough to unload the props.

Restarted the test...

If I slowly bump up the trim, I can alleviate the severe porpoise, but I mean it has to be a "tap tap" on the buttons. If I miss, she starts the cycle all over, and I have to tuck the drives in to get her under control. With this method I can get to neutral, but the steering becomes extremely vague. Steering inputs are delayed, and she feels loose. Looking out the back, she's throwing a steady prop stream with a near parallel pattern out about 100 feet behind the boat.

Neutral is at the Akash between 4 and 5.

I can get beyond the neutral point, but I have to tap the tabs incrementally, and increase the throttle. I took her to about 4200 with this method but ran out of room.

I think two things are hurting me.... nose cones and props.

Thoughts?

1. There is no need to have nose cones on a boat that goes under 80 mph, remove them.
2. Tapping is normal in my opinion, but I've only owned Formula's. The only time I can hold the trim button down is if I go from 3000 rpms and jam the throttles down. Otherwise my boat will also porpoise, but not as bad as yours.
3. From tucked to neutral should only be 2 numbers up from all the way in. For me 0 is all the way down and 2 is roughly neutral. I'd recheck your drive location at 4-5. For me 6 is fully trimmed up, yes I can trim higher but there is no benefit to it.

I'm assuming this boat is new to you. You are going to have to learn how to trim the drives. It sounds like you are realizing that a little does a lot, and it takes a few seconds for the boat to react to the new setting. Keep driving and experimenting, you will get it dialed in.

Yes, I had planned on removing the nose cones, but they wouldn't come off (the filler had cracked and I was going to remove... ended up repairing because they would come off the drives, and season starting). The nose cones have been on the boat for years so I didn't think was much of a factor. They will be coming off now, though not sure I can work on this at the marina.

Let me clarify the tap... I'm talking more a of quick jab/stab at the switch; maybe a half-tick of movement per tap. Anything more upsets thebboat. My 242 wasn't like this, neither my friend's Cigarette Bullet (that I'm very familiar with running). I'm not saying I'd hold down the trim buttons forever getting them into position; I'd do light taps to trim them out. This is different... you have to sneak up on it.

I'll recheck the drive trim indicators again this weekend, but I'm pretty sure that they're accurate. Is there a difference in trim angle with the TRS compared to the Bravo? I don't believe they're comparable, but what do I know? I can trim beyond the marked neutral spot and continuing gaining RPM and speed.

And yes, the boat is new to me, and I'm doing what I can to learn how it works. I've already logged a bunch of seat time, but there's always a need to keep learning. Yesterday was all about experimentation, and I think I learned a good amount about how she works, though I'm still scratching my head on some of these things.

When I went from my 242 to my 292, there was a learning curve in regards to trimming the boat so it wouldn't porpoise. I too do quick taps on my trim buttons, anything more than that and I'll over trim unless I'm going over 60. I still suggest moving to Hydro QIV props or B1's. Other than that, just learn what the boat likes.