cavitation plate

Just ordered a cavitation plate from Stiffy for my ride. I got it for a better hole shot and hopefully being able to raise my outboard up a bit more while on plane. Will it decrease performance or top end speed at all? Seems like anything you do to a boat to make it run shallower, makes it run slower on the top end.

I had to have one on my old 16.5' Skeeter Wrangler with 150 Black Max to keep the nose down and get a good hole shot. The plate should be pretty much out of the water wide open, it did not affect my top speed any.

If what you ordered was a compression plate it has the potential to increase your top speed a little. But your hull, whether you have a jack plate and trim tabs, and your prop are all factors. Without knowing your setup, I’d say “probably”, once you get it all dialed in.

That flat plate at the foot of the midsection is an ANTI-cavitation plate. Add-on products are "ANTI" as well, NOT "cavitation plates".

You guys not accustomed to flats saltwater boats, he's not talking about a holeshot or whale tail, it's a compression plate that does exactly that, compresses water coming out of a tunnel into the prop, which allows you to run shallower.

And to answer the question, it'll probably cost you a mph or two, anything that adds drag to the water will not speed you up. But, the ability to run a lot higher, improved holeshot and not cavitating in rough water usually more than offset the speed.

There's an interesting discussion on actual compression plate results on non-tunnel hulls on the Microskiff.com forums. The OP might want to see what the actual results have been from some of those folks. A friend of mine (who didn't participate in that discussion) who has the same hull I do (a Skull Island 16), which is not a tunnel hull, runs a compression plate (along with a jackplate) and he can run his outboard higher, resulting in less lower unit drag and a very small gain in top speed. Properly set up, the compression plate itself is above the surface when on plane, and does not create any drag. The primary advantage is that it allows you to run your lower unit higher, but it will probably have a detrimental effect on how your boat handles rough water or turns if you don't lower the jackplate for those situations. Originally, the guys who used compression plates all had jackplates and tunnel hulls, along with tuned props, but a few people experimenting outside the established norms have expanded the utility of these tools. Just remember, every hull and prop are a whole new story, and your results may vary. Being able to fine tune your setup is essential; small adjustments can result in large differences. Good luck with it.

Perhaps the OP can tell us a bit about his rig. I'm certainly not an authority on the topic, and I can't offer much in the way of predictions, but an idea of what kind of hull and power you have may help. If your rig is a skinny water rig, you might reach out to Jack Foreman at Crossroads Propeller Service in Port Lavaca. Many of us skinny water skiff anglers on the Texas coast (and beyond) consider Mr. Foreman to be THE skinny water boat setup guru; his knowledge and experience are awesome. Lotsa folks out there running his props. And I believe that he is a proponent of the Shaw Wing, which is the compression plate I'm guessing you ordered.

I've rigged out a lot of flats boats. Everything you've learned about setting up a bass hull is wrong on a tunnel hull flats boat.
First you need to understand how the tunnel works, and from there it gets easier. The tunnel uses vacuum to pull water up as the boat moves forward, depending on the tunnel design you can get enough water in the tunnel to raise the prop above the bottom of the hull.

When you choose to run a tunnel, you immediately give up any notion of a fast boat, the very nature of the design force the hull to be flat on the water for it to work, so regardless you'll have a ton of surface drag.

The compression plate is NOT a holeshot plate, it is designed to trap water out of the tunnel and compress it into the prop. Secondary it'll also act like a trim tab on holeshot, holding the bow down to get up and going.

Their effect on a tunnel hull is huge, their effect on a non-tunnel is small. They are part of the setup trinity, prop, hydraulic plate, and compression plate all work together to get the most out of what you've got.

Picture of my old tunnel skiff, so you can see how they all go together.

Thank you for all the advice. I look forward to installing it soon as it ships. If I loose a little on the top end it’s not a big deal. My top end now with a 4 blade prop on is about 42, but I rarely cruise above 30. I am running a 23 ft center console with a pocket tunnel.

Most people can't grasp how skinny a properly setup tunnel can go.

https://www.youtube.com/watch?v=SXLDKaVb0Vw