Add on lifting strakes

[Da Bull]

I`m thinking of adding some lifting strakes to the bottom of my Riot because it rides to nose high and to much wetted boat at the rear. Not enough tail lift. The Riot came from the Eliminator Scorpion which started life as a jet boat. When converted to outboard use Eliminator didn`t change the transom for more tuck or make bottom changes either. I know Mr Ron Baker did some mods to the Scorpion bottom that made it better then carried those changes over to the Riot but it still rides tail heavy. I`m thinking there`s more speed there if I can air the rear of the boat out some more.

I know what I`m going to do but not sure about what material to make the strakes out of. Any ideas?

DB

[RobF]

for testing purposes you can use pvc trim board, its easy to shape and you can glue it to the hull. this way when you have what works you can duplicate it in fiberglass. I would say coosa board glassed over should work well or consider making a simple mold. you might be able to use the same mold for both sides of the boat

[Da Bull]

PVC trim board? Is that something like house trim? Maybe something I can find at Home Depot? I like that idea. Thanks.

DB

[RobF]

yes some boards are stiffer than others try a lumber store they tend to have better quality stuff
you really only need one board

[bigboy]

What glue do you use?

Some wood might do the trick too.

[XstreamVking]

Better use some real good glue. Having one come off at speed could be tricky....

[RobF]

sand/grind the boat a little, you can get pre thickened epoxy in a standard caulking gun cartridge and set it up with that

you can of course use wood but the pvc board is easier to shape and work with and you can make the strakes from that as well later on so long as you glass over it

[Da Bull]

Sounds like a good plan. I`ll post my results.

DB

[Primal 98]

My boat bottom is complex with a couple of steps. I made up a basic mold out of aluminium angle. I waxed it, glassed it, filled the void with Epoxy and filler, then glassed the top. I glued these on with epoxy with filler to the hull while the hull was upright on trailer using jack stands to hold up in place, and tidied up the installation with fillets and filler to blend into the hull. Really happy with the result. Sorry, no pics of installed strakes. In the second pic, you can see that I glassed in a split pin so that I could tie a cable to it so it wouldn't be lost if they fell off during testing prior to final installation (never ran them prior to final fitment so cut out and filled). In the last pic, you can se that they were very flexible prior to installation.


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[Da Bull]

Aluminum angle for a mold. That's a good idea. That`s why I started this thread. Thanks

DB

[bigboy]

So DB have you made some yet?

[Da Bull]

Nope. Waiting for boating season to end. Don`t want to disable my lake ride just yet.

DB

[XstreamVking]

They make fiberglass angles that would speed up the process somewhat. http://www.libertypultrusions.com/pultrusion-products/angles/

[baja200merk]

I added strakes to my 24 Skater (why? cause when Doug Wright sugests something you do it). I had a local boat builder setup a jig to cut 1” high density composite on the Angle I needed then glasses it to the bottom. Made for a very easy install with minimal faring.

[Instigator]

Unless you get advice from someone like Kevin did, I'd do temporary install first.

I made/installed a set on a bow heavy (first) ski boat I had and it ran like crap! I peeled them off at the ramp and threw them away!

What your trying to do should be easier but angle changes a bunch.
Look at them at their begginings at the bow of various boats.
Some are almost horizontal while others follow the curve of the keel towards the bow and curve/bend up.

I'm infactuated by them and did a bunch of reading about them on offshoreonly.com over beers one night.
The story concluded (by knowledgeable guys) saying he thought they were invented to keep the Cubans from keep from sliding off the molds while waxing them ������

Bobby, if you get the strakes flexible enough you can duct tape them on to test.
Thats what I did and we did same on the kneel down race boats we were building in Houston, and same for lifting pads.

[baja200merk]

:iagree: i had the cabinet shop make wood blocks to stuff and extend the tunnels on one boat. All I did was silicone it on. Helped it air up but it hated more weight.

[RobF]

Unless you get advice from someone like Kevin did, I'd do temporary install first.


Bobby, if you get the strakes flexible enough you can duct tape them on to test.
Thats what I did and we did same on the kneel down race boats we were building in Houston, and same for lifting pads.


thats why trim board is good, its easy to cut, easy to shape, flexible, light, water proof, and you can adhere it to the hull easily.

[Da Bull]

All these idea`s sound great and I`ll get to doing it soon. I`ve watched several video`s of it running and there`s simply no transom lift. All kinds of bow lift but that's it. At 80mph I have about four foot of wet bottom. It don`t air out till over that. Tunnels are just so frikin wide and don`t squeeze much air. Also thinking about air flaps (afterplanes in boat lingo) on the back. I remember back several years ago Ruderiot on this site did some bottom mods to his Riot with much success.

DB

[Riverratt]

I had a similar issue with my Sleekcraft. You had to run it bow high for top speed and the ass drug. I always wondered if adding trim tabs at the top of the tunnels like a Stoker would help.

[XstreamVking]

With the problem you are describing, it might be a good time to add a small pencil roll to the trailing edges of the hulls before trying a drastic change like strakes. You have plenty of bow lift just need some lift at the stern which is what a small wedge would give. Tunnels are usually fastest when run flat. jm2cts