New to me boat porpoising

[triplebeard]

Sell the kick plate and get a Bob's kick-n-jack. I love mine.

And FWIW, you got the hull I've wanted for a while. Enjoy!

[wob]

I had an an 1844 GT for 20 years. Been looking for a 1644hd for a while.

[ecu1984]

The only thing I'll add to the above is that a dent (from going over stumps with a mud motor) in the under side of the boat can cause porpoising problems too. Just make sure there's not a large deformity in the bottom before chasing the other solutions.

This, if there is a "hog" in the bottom of the boat
It will porpoise like crazy

[Goin Coastal]

This, if there is a "hog" in the bottom of the boat
It will porpoise like crazy

Hooks will stuff the bow and make the boat run flat. Rockers will cause porpoising.

[Palmetto Bug]

Without special water pickups, there's only so much you can jack the foot up but is there no amount of down trim that will stop the porpoising?

What about trim tabs?

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[WatereesWatson]

Without special water pickups, there's only so much you can jack the foot up but is there no amount of down trim that will stop the porpoising?

What about trim tabs?

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Thats where the 15 degree wedges come in. I'd go that route before trim tabs on this type of boat. Itll increase the amount of negative trim to force the bow to stay down as you approach WOT.

[bunntyson3]

Thats where the 15 degree wedges come in. I'd go that route before trim tabs on this type of boat. Itll increase the amount of negative trim to force the bow to stay down as you approach WOT.

^^^^what I said the other day.

It stopped mine from proposing immediately.

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[wob]

Don't know if this is the outboard package on an HD model or not, but it seems beefy enough.

I have a question about wedges. What difference do they make if you have tilt and trim? Seems like all that would is increase the setback?

[wob]

Pic didn't load.

Oh well

[ecu1984]

Don't know if this is the outboard package on an HD model or not, but it seems beefy enough.

I have a question about wedges. What difference do they make if you have tilt and trim? Seems like all that would is increase the setback?

Transom wedges are installed between transom and engine bracket to give the engine more negative trim which forces the bow down.
They can add from 2 - 10 degrees positive or negative trim angle
Should be around $75 for a new machined pair

[Palmetto Bug]

Wedge or not, I'd still get trim tabs. Tabs came on my flats boat. I would have never ordered them on such a small boat. I don't want another boat without them now. They're useful for way more than keeping the bow down. I can get up on a plane faster and run in shallower water, level the boat when both dogs want to ride on the same side, slow my trolling speed down and get a bit more speed at WOT.

[wob]

I put trim tabs on any fiberglass boat I have, including a 15 ft high tide. Trim tabs would get destroyed on this boat in short order because of where I run.

Back to the wedges... I understand how they can make difference if you have to run with the trim all of the way down or up, but if you're running somewhere in between and you have electric tilt/trim, how does it effect anything other than setback?

[willyworm]

Without special water pickups, there's only so much you can jack the foot up but is there no amount of down trim that will stop the porpoising?

What about trim tabs?

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First statement is true. The idea is to find the sweet spot for all the variables involved. If top speed is the focus, jack that sucker up high as it'll go while still circulating enough water. For this type boat, I agree jacking it up to a stupid high level just doesn't make much sense. But you can still get as much of the motor outta the water to reduce unnecessary drag. Especially if he decides on a 4-blade prop.

Far as the porpoising part, think "what is root cause?" If you use trim tabs to address the porpoising you're treating the symptom while turning a blind eye to what's actually causing it. Why install trim tabs when it really just needs the right prop? Big fishing boats in the ocean, trim tabs can be game changer for sure. Flat running mud hull on small water? Trim tabs are overkill. Just solve it at the source and get a prop that allows the boat to run like it's supposed by providing that stern lift it needs and keeping the nose outta the air allowing the boat to run level.

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[Goin Coastal]

Wedges aren't your answer. Look at your pic. You are trimmed almost to tilt to get it level in that pic. Trim it all the way down and take a pic. With the boat transom angle and the added exaggeration from the breakaway plate you should have plenty of negative trim tucked under already. Unless you are running the boat tucked under, adding wedge won't help. If your hull is like my Gator Trax hull, 1650 with V bow surface drive, it hates weight forward. Try running it with a full cooler up against the front deck.

EDIT: Unless you are talking about adding wedge to the transom running surface and not motor/kickoff mounting. Basically a trim tab.

[Sheep]

I'm just seeing the pics ....that motor looks extremely too low....


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[willyworm]

Far as the angle, I had a similar issue with my Xpress 1651. I had a buddy weld some wedges to get the right angle or else I wasn't getting the use of the majority of my trim travel. I didn't have to trim up very much before I was getting just tilt.

A visual depiction:

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[wob]

I had a guy riding in the front and tossed a 45lb plate in the front hatch. Rides great like that. Hits low 40s running upstream with no porpoising. Prop blows out when gunning it. Next move is to change props.