Adding Strakes

[Cowracer]

Assuming you have access to someone who is knowledgeable and equipped to weld aluminum...

Can lifting strakes be added to an older boat? If so, can the strakes be purchased and welded on, or do they have to be 100% fabbed? If I have to fab them, where can I get drawings/dimensions/plans?

Finally, my 25' Bennie with a 125 runs about 24 with 3 people. What kind of speed gain can I expect from adding strakes? Or would adding a 3rd toon yield more speed?

Anyone who suggests tap fins will have a box of the Ebola virus UPSed to your house.

Thanks!

Tim

[Bryden24shp]

Anyone who suggests tap fins will have a box of the Ebola virus UPSed to your house.
Thanks!
Tim

Rats!!! I was sooooo close! You can add them! Check with http://elementfabricating.com/portfolio ... g-strakes/ I would look around for local welder willing to tack them on.
Good Luck!!!

[Bamaman]

If I was going to add lifting strakes, I'd first want to have a really good pontoon boat to add them to. No use spending the money if the boat's not first class and worth the additional investment. And the motor needs to be up to the job--no 60 hp motors.

Bennington and other manufacturers just don't weld some aluminum angle to their toons. They actually spend time engineering the angles and lengths of their strakes. And they test their strakes for performance.

I'd go to a dealership and find a boat comparable to mine. Then, I'd take measurements of their strakes' placement and length and angles--copying what the factory's done.

I'd be looking for a quality welder that's really good with TIG welding on aluminum. Not every welding shop is great welding aluminum, but there are some good fabricators out there.

[rockhound]

the new to me toon does not have strakes, it does have a 135 hp i/o motor

this modification is one that interests me also.

over the last month or so i have looked at all kinds of photos of home-fabbed as well as factory strakes, patent applications and their diagrams. more often than not the strakes although not actually angle metal they are pretty damn close, and many are just that

the ones that are angle metal and factory installed are taken a bit farther down so as to be past the horizontal plane and form a shallow pocket if you will,

there are other designs that have a slight curve in the underside surface with mimics the same pocket.

they are all parallel to the decking of the boat. There is some variance as to how far forward they go toward the nose cone, a simple google search for "lifting strake photos" yields dozens and dozens of factory built lifting strakes that are just exactly that "angle metal"

lots of them are simply flat to the water's surface.


I am not an engineer, but i am or at least was for a long time a builder, fabricator, I have built everything from custom cabinetry to custom off road suspensions from scratch.

I see some things that is like about the angle metal design.

1. simplicity
2. more than one manufacturer using them (a consensus of design)
3. some of the more angular designs i feel give more ability to cause drag in a turn by giving a top side angle that would grab water, the angle metal top side would almost shed water if the metal was positioned properly on the log
4. availability, i can get this metal in several places locally.
5. definitive reproduction, extruded at the factory the next piece will most likely be an exact replica of the first.

As far as attaching them to the tube, the issue becomes fatiguing the metal or causing holes.
How do you get the strength of a weld without overheating the aluminum and blowing holes in your tube?
I believe this to be a viable way of attaching a set of strakes to a pontoon. How about an aluminum soldering method that yields 49,500 psi of tensile strength, non-corrosive, that melts 500 degrees before aluminum and can be used by the average joe, can be used to weld, fill holes or even make new parts for any type of aluminum:
http://www.aluminumrepair.com/video_new.asp

I plan to make new strakes for my rig, they will be angle metal just as many factory built tubes have. I believe this brazing rod will make a more than adequate connection between the boat and the strake.

[BoatCop]

The one thing that always comes up when adding strakes in tube warranty. I think Bennington, and a few others, offer a lifetime warranty.

I know that Tracker will void the tube warranty for any welding done on them.

[rockhound]

I would doubt that my third owner 1997 tube is under warranty

[willy13]

Does anyone know how much elementfabricating charges for there lifting strakes?

[Bamaman]

Rockhound:

I don't know that you really have the motor that would/could take advantage of lifting strakes.

I've had a 140 hp/3.0 Mercruiser in an inboard outboard v-hull runabout, and it performed more like an 85 hp 2 stroke motor. And it ran best at medium speeds--being pretty weak at low rpm's. But all I/O's will run prett fast on top end due to their having power trim.

Most think straked hulls are best when reserved for 115 hp or more outboards.

[Liquid Asset]

Yes strakes can be added to any boat. I added them to my 1983 when I did the rebuild. I copied manitou's design when I made mine. My center log is set lower just like theirs also so I figured that style strake would be best. My boat does actually lean in the turns after borrowing their ideas ! I bought a couple of 1/8'' sheets cut them and took the pieces to a local shop with a hydrolic brake. I just bent a 4" piece in a vice to show the shop what angle I wanted. Most all of the oem. strakes are extrusions vs. bent sheet. Make sure you have a good welder because working on old aluminum is a different beast than new. My tritoon is only powered by a 90 and tops out at 25 mph due to 19" logs. However my boat actually gets up on plane unlike most pontoons, I can just back the throttle off and stay up all the way down to about 14 mph. When I had a 115 on the boat it ran at 30 mph. Just this past monday (memorial day) I had 2 different guys come up to me at the launch wanting to see how big of a motor I had becasue they had never seen a pontoon get ontop of the water. They said that they figured it was "bigger than a 90" , and I then explained to them what strakes can do for a pontoon. My 2 sheets of aluminum, blade to cut it, and paying for the bending cost me $400 ,oh and a case of beer to have them welded on ! My good friend is a professional fabricator and has done all of the welding mods on my old riviera cruiser.





and after I painted the logs and polished the strakes

[rancherlee]

You don't need tons of power, my 70hp puts mine up on the DIY strakes until I get 5-6 people on board. Just me, the wife, and daughter I can stay up on plane down to ~17mph. Can't wait to get a 115hp on her.

[pond tuuunes]

here is the best shot of my strakes.JT

2.jpg (132.03 KiB) Viewed 5881 times

[wrd1972]

Anyone who suggests tap fins will have a box of the Ebola virus UPSed to your house.

Thanks!

Tim

Just wow at the violence on this board. Death inducing hemorrhaging and organ failure may be a bit over the top. Seriously!!!!
Consider UPSing this instead http://crabrevenge.com/

Go for the devastating RED package.

[fiddlebick]

Tim, I am literally in the same boat as you. My 05 2575 rfs benny does about 25 tops with two people aboard. I have a 135 Honda, which is the same size weight motor as the 150 Honda, less the variable valve timing. I am still considering adding an express tube, but as of yet can find nobody that has done so on this size boat. I won't pay the price unless I can be assured of at least 5 mph increase. Two nearby dealers cannot say how much I will gain. I would be pretty disappointed if I added a tube with strakes only to gain a mile or two on speed.

[rockhound]

Rockhound:

I don't know that you really have the motor that would/could take advantage of lifting strakes.

I've had a 140 hp/3.0 Mercruiser in an inboard outboard v-hull runabout, and it performed more like an 85 hp 2 stroke motor. And it ran best at medium speeds--being pretty weak at low rpm's. But all I/O's will run prett fast on top end due to their having power trim.

Most think straked hulls are best when reserved for 115 hp or more outboards.

I just picked her up today so I dont know how she will run, the guy we traded boats with says they can ski behind her with no problem, that remains to be seen as I have not splashed her yet. First order is a new carb tuned for altitude, the right prop and we will take her out for a shake down run

[rockhound]

The closest performance numbers I can find is a 25 foot party barge with my engine set up and no strakes or other performance enhancers, magazine reviews from 2003 are saying the 25 foot barge is a 27 mph boat from the factory, seems that would be fast enough to take advantage of strakes. My rig is 24 feet and basicallly the same rig