Jet Jon Build Pics ...VIDEOS LINKED!!!!!!

[Ride_Klein]

Video helps.

You mentioned in an earlier post that it ran better without weight up front. Were you referring to top speed or was your cavitation problem worse with the added weight up front?

Looks like you might have a small problem with porpoising as well. (Boat wanting to bounce up and down on plane in pretty smooth water) Was this simply from hitting your own rollers, or does the boat bounce as you approach top speed? If it does porpoise, that isn't helping your cavitation problem any. You can remedy porpoising a couple of ways. The easiest is to simply add more weight up front. Use something you can move easily while running and see if that fixes your problem. Of course this solution is pretty useless if more weight up front makes your cavitation problem worse.

Other solutions for porpoising include trim tabs or adding wedges to the hull.

Example of wedges.
https://www.duckboats.net/cgi-bin/forum/gforum.cgi?post=27369

You can test wedges pretty easily using a piece of wood that's taped to your hull with duct tape. This lets you try a couple different degrees and sizes of wedges to see if they help before you do any major work.

You should be able to use the same technique to test any spoon modifications. Get some shape-able foam blocks from a craft store and mold/cut them to your desired shape. Tape 'em on there and hit the water. You can test a couple different setups this way without having to permanently modify anything on the boat. They won't hold on all day, but when they let go they're easy to find.

 

[majkowskid]

it does porpous just a little bit when i'm the only person in the boat. with a friend up front, it's completely gone. i think once i get another battery up front for the trolling motor this will be completely eliminated.

i was thinking about trying out spoons like you said, but would tape really hold at all? i would doubt it. trim tabs are an option for the porpousing as well....

 

[Ride_Klein]

The tape won't hold it all day, but it will hold it much longer than you'd think. I've used it in the past to test wedges, flotation pods, and adding hook to an old ski boat hull help flatten out a nasty bump in the wake at 28' off.

The trick is making sure you get the hull completely dry before you tape things on. This is much easier to do in the shop, but with enough towels you can get it done on the trailer as well.

 

[PSG-1]

hmmm....

that's really weird psg... so basically you have a similar hump in front of your intake, and didn't have the issues. only difference is your intake grate.

i really think i'm going to try that first... just get a top loader grate. i'd rather try a bolt on accessory before i go and start glassing. i figure it's a good upgrade to the boat anyways.

Well, I never said I didn't have any issues with cavitation, because it will cavitate if you try to take a curve at too high of a speed, and it will cavitate when you get in chop that's more than 6 inches in height. But in light wind chop, and under most average conditions, no problems.

I had less cavitation with my top loader grate, for sure. But again, I wanted a weedless system, so, I had to trade off one advantage for the other.

BTW, here's the modification I made to the center strake:


OK, maybe not exactly flush cut, but definitely flattening out the V for a couple of feet like I mentioned.



Ideally, and on the next build I know to do this.....take out the ENTIRE center V of the boat, and weld a piece of 1/4 x 2" or 1/4 x 3" flat bar along the entire length of the cutout. I didn't do it on this one, because the boat was already built, and once you get forward of the engine compartment, there is foam in the hull, I didn't want to burn it up with the process of welding, and I figured at least by reducing the V for the length that I did would have an effect. And it does.

Taking out the V and using 1/4 plate, removes the center V, but still gives a lot of structural integrity by using a piece of material that's twice the thickness of the hull itself.

 

[mmf]

I LOVE your videos! Very comical too!! I like the REDNECKIN especially! Keep up the good work!!

 

[PSG-1]

I LOVE your videos! Very comical too!! I like the REDNECKIN especially! Keep up the good work!!

By 'redneckin' I assume you're referring to the clip of me and Larry The Cable Guy out harvesting oysters? Yeah, that was some funny stuff! It took him about 45 minutes to get out of the mud, and his camera guy was buried even worse, it took 3 of us to get him out.

 

[majkowskid]

well, i bit the bullet and ordered an intake grate for the boat. should be here monday. it's used, but in great shape, and it should fit my ski (it's hard to find accessories for an xl700 yamaha hull!) plus it was next to nothing in price.


i want to see if that helps at all first. next thing i'm going to do is get some sponsoons for the side of the boat to help in the turns.

i'll keep you guys updated.