New to RDP and so far awesome, I have a 2007 ultra 23 shadow deck and I am having a porpoising issue, anyone have a fix for this? I trim up just a little and bounce bounce, trim all down and smooth as can be.
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I'm confused. My understanding is porpoising is the word to describe the bouncing motion you get when you hit a bump at speeds while on plane.Ok no porpoising issues at cruising speeds, another guy told me he has a whale tail also but he is always full speed stop, full speed stop lol
I'm confused. My understanding is porpoising is the word to describe the bouncing motion you get when you hit a bump at speeds while on plane.
When are you experiencing said porpoising?
I know I've asked before but are you running a 496mag? The 23POk so update, trying a 5 blade 23p and it is a night ans day difference. Porpoising has minimized and Rpm has increased by 400 rpm. Still does porpoising but it is 100 times better.
next step is to try one of those whale tail thing.
the fix is tunnel tabs......... what happining is the boat doesn't go fast enough to pack air and carry the hull, porpoising is when the boat can't decide to run in the water , or on top.. air lifts the hull in the tunnels, but the bow weight brings it back down... if you look at stoker/ schiada... they have tunnel tabs to trap the air in the tunnels,... thats why they will run in the 80's with 500hp.... take the tabs off and they will start hopping........ I would put fixed tunnel tabs ,... and I would put purple ones ( because I have a set) when I prop a boat, I first identify the issue.... that boat will always have a hopping issue with out trim tabs,... unless you just drive it slow.... to get the max out of that hull, it needs to pac air.... cheetah stelleto's have the same problem... but, they made the tunnels so big the speeds under 70 they don't perform well,... I heard , (rumor) theres a guy running one with speeds north of 120 mph, never seen a pic of the boat though...
Porpoising happens when the center of lift moves aft of the CG. In the normal way of things, the center of lift starts just a little aft of midships. As speed is gained, the lift increases and moves aft as the hull rises out of the water. This cause the classic pitch up seen in most planing hulls. As speed continues to increase, the center of lift moves aft with the decreasing wetted surface. When the lift moves aft of the CG, the boat experiences a rapid pitch down which leads to the wetted surface increasing and a huge increase in drag, which causes lift to be lost which whith the increase in wetted surface forward moves the lift forward of the CG and starts the whole cycle again.
The major reason for jackplates now seen on modern high power OB boats is to get the CG aft enough (i.e. the engine weight) to allow the full power of the engines to be brought into play to achieve maximum speed.
Nope, Went bigger this time. The lake has just gotten too rough for that hull. They offered it back to me for 7k but I passed.I am defiantly learning to drive it and find its sweet spot with trim. I really do like this 5 blade prop. Sorry about your boat, I hope you were able to salvage it?