Jet Tunnel Issues!

[fishbum]

Hi Guy's. Still working on my new sled it has a 3" tunnel that is not working. 1st try motor up high with intake tucked up under the tunnel extension (the tunnel extends about 3" past the transom) at this height it blows out, cavitates, ect!
ok so I had a plate welded in the tunnel dropping it to about 2" that is working fair. You can't get the intake up as high as you would like in the tunnel because it hits on turns. What I am wondering is can I back off with the motor and have
it just above the tunnel as if the lid of the tunnel is the bottom of the boat? I have had several factory hulls with no tunnel and used a 4" jack plate to get the height up and that works real good. seems like the water flows up off the bottom and into the pump. all of those boats I could trim the motor a good bit to raise the front of the boat to run faster
or not get wet in rough water. with a tunnel and the intake tucked under you can't trim it then lets the water flow over the intake and makes a mess. also on the thread of jet pictures I see a bunch of those plates above the intake on the high performance boats. what are they and what do they do? Thanks

 

[S&MFISH]

also on the thread of jet pictures I see a bunch of those plates above the intake on the high performance boats. what are they and what do they do?

I can't answer for the rest of the guys. For us it serves two purposes, one it gets up on plane quicker, secondly it eliminates the porpoising that the boat does when I trim the jet up to eliminate the excessive splash into the boat. It has no splash plate on it.

 

[fishbum]

Thanks s&m what is the plate called and where do you get them Thanks

 

[S&MFISH]

Thanks s&m what is the plate called and where do you get them Thanks

Fishbum,it's called a whaletail,and I got mine from Troutt andSons,out of St.James,MO. Here's a link...https://trouttandsons.com/AquaBoss2/aq-show.php?listid=119039427568067&page=10&p=5&s=make ASC

 

[fishbum]

Thanks, what does it do for you? pro and cons?

 

[S&MFISH]

All pros,no cons. Has to be the BEST accessory I've purchased.
First off-it helps the boat getup on plane quicker.
Second- When I trim the motor up to stop the excessive splash into the rear of the boat(has no splash plate), the boat would porpoise violently. The tail eliminated that.
Third- It serves as a step to reboard from the rear.
Hope this was of some help to you.

 

[Lil' Blue Rude]

Hi fishbum, are you asking about a spray plate or a whale tail? whale tale bolts to the jet the spray plate bolts to the boat.

 

[fishbum]

Hi fishbum, are you asking about a spray plate or a whale tail? whale tale bolts to the jet the spray plate bolts to the boat.

Whale Tail.

 

[Lil' Blue Rude]

one con. Slows you down.

 

[Kevin Turner]

Hey Barry-
Sorry to hear of your recent struggles. Many things come into play when setting up a tunnel craft. As to the Whale Tail, I used to run them on all my early boats. We'd install transom wedges to increase the jet foot "tuck". Combined with the increased downward angle of the thrust and the increased angle of the whale tail, it would launch our *** heavy (read 200HP/all batts/fuel in the stern) 52-56 wide bottom hulls quicker. once on plane, the tail would deflect the spray coming off the bottom downward to help with porpoising.

In your case, with a better center of gravity (read batts forward/fuel cell center) for level static drifting and slower speed planing, the whale tail won't have such a dramatic effect. Coupled with the fact that you jet foot is all ready higher in the water, the "hydro foil" lifting effect will be minimized.

Also, the tail will not work with poly jet foots...

 

[fishbum]

Thanks Kevin, this seems to be a funny hull, I keep getting bigger as the years go by and it is getting harder to get what i want out of it. Barry