Boat trim - am I missing something?

I have a 43' Ocean and they are somewhat notorious for poor following sea performance. A combination of narrow transom relative to mid-ship beam, small keel and flat aft section built for speed are all reasons I've heard. Interestingly, I find the handling in following/quartering seas much worse with small wakes in otherwise flat water. If I get caught with one of those while the bow is trimmed down, the boat can do some pretty surprising rolling and yawing. Her nose will get pushed down by the swell and want to bow steer. In bigger seas the motion is not great but not nearly as crazy. And I don't get caught by surprise by prevailing sea conditions so I know not to be trimmed down.

On my boat I've learned that in following seas, I remove all trim tab and get the ass of the boat to sit down. I play with the speed to match the swell as best as possible. And I generally have much better handling with the AP ON. Unless I'm in a narrow channel or for a brief period of time, I'm better off with the AP steering.

no, I mean it’s totally normal for a 42-46’ post to do this. They, oceans, and some Carolina sf are not good sea boats with the waves a aft the beam.

There is a fine line between sharp entry bow with good down sea handling and outstanding head sea performance and one that doesn't. Change to much and ride suffers in one sea state or the other. The newest sf have really dialed it in. The original single engine Carolina boats that needed sharp entry to fish typical outer banks conditions had small keels running considerable length to reduce broach.

Yes, but....and that's a big but. They'd also have negatives and change the handling and performance in other ways. His situation doesn't call for such drastic action. Just learning, adjusting and accepting.

Another thing that helps with our sized boats is that magic 15' water depth. Anything less my boat starts to pull a long big wave off the aft quarter. The shallower it gets the more the wave lengthens and the bow tends to start rising up. I draw 3.5 feet. I would say you are close to the same.
Anything under 12 feet I pull her back down off plane etc. for me 1400/1600 rpms = 8/12 knots depending on the current. It's not deep enough IMO to hammer along and create all that drag .
Others here can explain the water forces here better than I.
I guess I'm talking '' displacement'' ?

Anyway take notice when you go over and under that 15' mark to see how your boat reacts.

I know that's right!

BUT, I'm boating, with out payments......

@Greg Page - if I recall your vessel was repowered by the prior owner. Is there a significant difference in weight between the outgoing DD and the new motors? How about placement of that rotational mass fore and aft? Where are your batteries what sizes and how many?

Has anyone noticed a performance difference in a following sea running w/o curtains on the bridge? A big spinnaker like that would certainly push a garvey around on a windy day.

Are you sure she drinks diesel and not Mic Ultra or Truly?

Do you keep your freshwater tanks full? Anything below the cockpit between the fishboxes?

This issue fascinates me b/c I am always running in the slop that @Prospective describes above as the jet stream crosses Lake Michigan. Consistent 2-5’ chop with a high wave frequency - steep on both sides.

We took the boat out Sunday afternoon in 4 footers for an hour or so before going to the gas dock for a fill up and pump out.

Less than 1/4 in both diesel tanks, freshwater tanks were also nearly empty and the s**tter was full Cousin Eddie style. I have a pair of 8Ds between the motors that I wish I could relocate to the bilge as close to the rudders as possible.

The uncontrollable bow steer and sudden keel catch in following seas seemed to be even more pronounced and less predictable on Sunday and I am of the opinion that this is more a matter of weight distribution and balance before speed and trim tabs.

We are running to Chicago this weekend (sans children) 108 miles straight shot each way. We’re expecting 2-4 head seas outbound and 2-5 following on the return. We’ll be fully loaded with 550 gallons of Diesel and full freshwater. If the NOAA and Windy forecasts are accurate, I should have a good block of time to test these variables at cruising speeds. I’ll let you know how it goes.

The jury is still out - NOAA forecast changed Friday morning. Consistent 20 kts SW wind and we crossed in unforgiving 6’ head seas with a high frequency. Changed direction a few times get a better ride and ultimately had to out run a thunderstorm that welcomed us to MKE for the final leg south. The return trip was almost perfectly flat. 20-21 kts cruise ~120 miles. I am asking Santa for an autopilot and a new MFD for Xmas. Hopefully we’ll have a chance to experiment with sketchy following seas on the next trip.

That said, I am curious about how the trim tabs can positively (or negatively) impact efficiency at cruising speeds. How far can one go on 500 gallons with 671s?

@Greg Page - with the repower, what stats are you pulling when the conditions are right? Does the bow naturally settle when the boat is fully on plane? Will she skim on glass like sn overpowered bay boat?