Pulling a tube

[z33tec]

So I'm a fishing guy and have a boat setup mainly for fishing. That said, my daughter is old enough to go on a tube herself and did so this past weekend and now she's hooked. I actually bought a tube earlier this summer but never got around to testing it out on my boat.

I took it out tonight to see if the connections worked on my boat. They kind of did.. I connected it to the two rings on the transom but the rope sat too low in the water, and closer to the prop than I'd like. When I tried to give it throttle I was having issues with cavitation, if thats the right term for it.

Any tips or ideas on how to mount the rope higher? Pic attached of my test run.

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[Steve H.]

You should have no problems towing a child on a tube with a 70 hp. They make rope floats that add buoyancy where the two short sections come together, though I'm not sure that's your problem here. What time of "cavitation" problem are you having?

 

[z33tec]

You should have no problems towing a child on a tube with a 70 hp. They make rope floats that add buoyancy where the two short sections come together, though I'm not sure that's your problem here. What time of "cavitation" problem are you having?

The proper word might be "ventilation", and thinking back on it, if you look at the pic, we were in a super weedy area (was looking for a spot that was calm so I could mess around with the ropes) and the weeds may have just fouled the prop up a bit so when I went to accelerate the RPM's just shot up and didn't get any bite. Was pretty sure I was fully trimmed down but who knows, was getting dark and was messing about so may have not had it down completely.

My main concern was how close the rope was to the motor when I turned it. The prop is certainly under the water and there's a very small "float" on the V part of the rope, so it technically shouldn't go near the prop, I'm just cautious.

I started looking at those "booster balls" that you can add in line to keep the rope up higher in the water. I think that will probably solve my problem. My other problem now is where to put all this damn stuff in the boat now lol. Always need a bigger boat, right?!

 

[KMixson]

I have never pulled a tube before so my idea might be way out there. How about running floats down the rope to the Y. Then run a length of PVC pipe down both ropes to the floats. Leave enough rope exposed to tie onto the rings. That way the loose rope would not be near the prop. I don't know what size of PVC would be best to balance between being stiff enough yet flexible enough to keep from cracking. Maybe use PEX tubing? Someone on here may have a better idea that they have used before.

 

[gogittum]

Waaay back in the early '70s, I owned a 16 ft Tahiti ski boat with 115 Mercury. It's a low freeboard boat and had a tow setup similar to yours, but with more widely spaced anchor points on transom, which meant a longer "Y" in the bridle. It was made of, I think, braided polypropylene ski tow rope, which floats.

Sinking rope would be a major hassle and almost guarantee getting in the prop. Bridle had a single fairly large float at the Y. It worked fine for the 2 years I owned the boat. We did a "lot" of skiing and never did get the rope into the prop....but never, ever put it in reverse with bridle in the water. That would be begging for problems.

It worked fine, but was really too low for best performance. The jet boats all had a chromed bracket with tow eye mounted higher but those were pretty spendy and somewhat awkward with the tall, narrow Mercury. Height of the motor, trying to tilt the motor....etc., etc.

If you could get your attachment points higher on the transom, as close to top as possible and spread them out to the gunwales, it should work fine. I like the idea of PVC tubes on the bridle, but they'd be awkward when bringing them aboard.