I think that the best overall performance comes from the prop and the running surface being parallel with one another and both being as close to parallel with the water surface as possible. Tabs are handy but they reduce speed and efficiency. I would try to move as much weight forward as you can first, then use tabs to get the rest of the way there.
And now for the unsolicited advice from the peanut gallery!
At the risk of stating the obvious I will point out that porpoising happens when the running surface of the boat becomes shorter at speed and it is directly related to weight distribution. It is in essence an attitude problem! With a stern-heavy rig the running surface will quickly shorten to the rear as the boat accelerates, leaving the bow suspended out of the water and the aft portion of the hull in the water. The dynamics that lift the bow out of the water through acceleration are reduced as the boat speeds up and less hull remain in the water. The forces that lift the bow are eventually less than the force required to suspend the weight of the bow in midair so the bow falls. After the fall more hull is in the water creating more lifting force on the bow and up she goes again! Most of the time the weight distribution problem is caused by too much motor weight. Even in new boats that are “designed” to carry larger motors there is a marked “squat” when the boat is floating at rest. It is only a guess on my part but I believe that over the past decade or so, manufacturers have beefed up their transoms to accommodate heavier motors (more HP + 4-strokes) without redesigning the overall weight distribution to optimally support and balance the extra motor weight. Just strap on a big motor and add tabs as standard equipment and voila! Not a bad fix really. Boats with big motors and trim tabs are easy to sell (and that is after all the whole point to making boats).
Basically anything that can cause the boat to run more level and maintain a longer running surface will fix porpoising problems but it is worthwhile to consider the side-effects of the fix. You could install a smaller lighter motor to create a well-balanced rig (I know, “get thee behind me, Satan”!). I think this is actually the best solution when considering new power but I am probably in the minority with that. It certainly is not a viable option to fix a little bow bounce on a working boat. You could add trim tabs. These work by trading drag for stern lift. The cost is some efficiency (in my case, with full tabs, I lose about 400 RPM and 5-6 MPH at WOT while still burning the same amount of gas). I use my tabs to even the load left to right or occasionally to lower the bow when running into chop. My rig (not a Seacraft) is pretty well balanced so I don’t need tabs most of the time. Someone mentioned adding sand-bags for weight in the bow. I think that too is a tradeoff but probably a little better one than buying and installing tabs; it creates more drag from added weight but still keeps a flat running surface. That seems like less drag than trim tabs would create. Another fix is the prop but I honestly don’t know how that works. I don’t understand how a round prop facing forward along the planning surface can create upward lift at the stern but I don’t know much about props. Someone more knowledgeable that I can explain that.
I only mention all of this because this forum is built on members who are enthusiastic about Seacraft hulls. This innovative design still has a lot of advantages when compared to similar modern boats. The Seacraft advantage is below the water line and it runs bow to stern. If a boat is stern heavy it drags a V-shaped groove on the surface of the water that is deeper and wider than the same boat running the same speed with a well balance load. You’re basically driving a bigger wedge into the water with the bow up than you are with a more level riding boat. If you are going to pile lots weight and HP on the transom then the Seacraft “flying wedge” really isn’t any better than any other “flying wedge” out there, since the stuff that makes it a great hull is suspended in mid-air.
My 2₵!
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