Bayliner Capri....ski/tow bar?

[MikDee]

Re: Bayliner Capri....ski/tow bar?

I didn't know this....don't tow a tube with a skibar? So whats the best way to tow a tube (and why)?

Neither did I? but I'm guessing apparently it's a lot more drag on the bar in all directions,,, I'd say tow tubes from the rings on your transom.

 

[45Auto]

Re: Bayliner Capri....ski/tow bar?

The tube can put a lot more load on the skibar than a skier can. A tube is a tremendous drag in the water. If the rope goes slack (which it easily can if you are swinging the tube back and forth across the wake), the tube slows down immiediatly. This gives the boat a running start at the rope until it snatches tight, and the load from the tube can yank the skibar right out of the boat. It'll pivot around the upper supports as it rips the screws out of the plywood floor. Could really hurt somebody. Safest way to tow a tube with your boat is with the Y-harness shown by Quadmaniac in the earlier post, attached to the aft tie-down rings.

 

[Bigprairie1]

Re: Bayliner Capri....ski/tow bar?

So would I assume that these waketower boats shouldn't be (or aren't) pulling tubers with that apparatus?
The 'tube drag' makes good sense, I just didn't know that these tow systems were set up to handle tubes.
Glad I didn't try that yet.

 

[45Auto]

Re: Bayliner Capri....ski/tow bar?

It's possible to build a tower that will safely tow a tube. You just have to have enough reinforcement behind it to distribute the load into the hull. The problem is the load due to the moment arm and "snatch" load. But it takes more reinforcement than 3 or 4 #10 screws into the plywood floor, and a couple of struts screwed to the rear fiberglass deck with very little reinforcement behind them like a typical ski-tripod is constructed. I've never looked at the tower mounts on one of the factory waketower boats but I would bet that there is some substantial reinforcement behind them. If you don't have "bulletproof" mounts, then you have to be careful of the loads you apply to them.

SportsStuff (makes lots of different tubes) gives some suggested rope strengths in their manual:

http://www.sportsstuff.com/manuals//57-1522.pdf?PHPSESSID=a4e5dacc8fdb0c6bcfc6e223087c77c3

For 4 people on a tube they recommend a rope tensile strength of over 2 tons. How would you feel about suspending your boat vertical, then hanging a couple of Chevy Suburbans from that ski pole? I wouldn't walk underneath it.

The 5th-8th bullets in the right hand column are their recommendations on pylons.

All that being said, I have pulled many tubes from a tripod ski-pole like you were talking about. I just sold my 18', 1996 Bayliner bowrider with a 120 Force at the beginning of this summer. It had the ski-tripod like you are talking about. The secret is to keep a constant tension on the line and not to let it snatch. If you have a 1000 pounds of tension in the line, then the screws in the floor 3 feet below the struts are seeing a 3000 pound sheer load. And those plywood floors have been known to get soft. Multiply that by 3 or 4 for the snatch load and you can see why it is not advised for tubes.

PS - I am a structural engineer in my day job. I sit at a computer all day trying to figure out how to dump ridiculous loads into structures in as light a manner as possible, so I was very aware of how I was overloading my ski-tripod! I made very sure to keep the rope tight. Lots of things are possible if you are aware of all the risks and limitations of your equipment and technique, people get into trouble when they don't understand all those factors.

Keith