Sonicwake 36 porpoising Like crazy

[Jessejames]

trying to figure out this boat to stop porpoising ..not new to the hobby and been trying numerous adjustments and seems to run only smooth with slight turning to the right with it ...Constantly messing with these trim tabs ...driving me nuts lol...Any suggestions?

[Bushmen77]

trying to figure out this boat to stop porpoising ..not new to the hobby and been trying numerous adjustments and seems to run only smooth with slight turning to the right with it ...Constantly messing with these trim tabs ...driving me nuts lol...Any suggestions?

I lowered my trim tabs and it went away.

You might try to put the strut stright and put jusr a little Negative like 2mm n the tabs. Been there the just a tiny move on the tabs is huge. My voracity that runs Like a rap ape I use 2mm negative on the tabs. So I matched that on my sonic wake and she running great. Leave the tabs there and play with the strut angle. Good luck

[properchopper]

From IW 2011:

Porpoising is a common trait of performance hulls - power catamarans, vee hulls and vee-pad hulls in particular are susceptible. Each boat has it's own unique speed at which is can experience the transition through phases of planing performance. This transition speed is called the "hump zone".



All such hulls are planing on running surfaces and get their performance from a combination of hydrodynamic (water) and aerodynamic (air) Lift. The transition of the Vee-Pad hull to "running on the pad" can cause dynamic instability. Here, the hump zone represents the speed at which the amount of Lift from the highly efficient "pad" section of the hull (aftward, center located, flat planing surface) becomes significant compared to the Lift generated by the veed (full length, higher deadrise) portion of the hull.

Porpoising comes from a rapid change in the location of the center of Lift as the boat accelerates. The location of static weights is one way of dampening the rate of change of the CofL...so it's not always obvious whether to move weight fore or aft in order to cause the "dampening". The solution can be calculated, but we use software for that. It's not too difficult for you to find out through testing, whether moving weight fore or aft will help your particular problem.

Propeller selection can often change the dynamic balance of the hull/setup. For example, a change to a prop that provides more aft-Lift can alter the dynamic balance of the hull, and similarly change the speed and range of the "hump zone" ? often eliminating porpoising. Weight distribution changes can also have a positive effect on "where" the "hump zone" will occur, as can change in power application. Changing "trim" angle while driving through the "hump zone" even if less efficient, will also provide a better experience, and when well controlled, can "close up" the range of "hump zone" substantially ? eliminating porpoising.