Towing Water Skiers from A-Frame?

SimonCh · 13 February 2013, 21:54

Whats the general consensus? Would you guys feel comfortable towing a water skier from your A-frame? i've been doing it and it seems to be ok, as the Tornado comes with a pretty damn robust double a-frame, which seems well secured to the deck and transom. But a friend of mine with a RIB thinks its awful that i do it!

Si

Oscarguitar · 13 February 2013, 22:38

Depends on the boat and frame. If it has the "ring and peg" fitting it should be fine.

Peter_C · 13 February 2013, 22:45

If the frame is designed to tow with yes. If not NO! The forces generated can be incredible, and it is a shock load.

Notice the width between the tower legs. Also these have plates underneath the gunnels to spread the load out, and I have seen many boats crack at the tower mounts.

NEVER tow a tube aka ringo from any tower.

Crusher · 13 February 2013, 22:59

Quote:

Originally Posted by Peter_C

NEVER tow a tube aka ringo from any tower.

Why??

ajstars · 13 February 2013, 23:15

Surely towing from the transom will load the transom more than towing from an a frame that's bolted to the transom and the hull?

Peter_C · 13 February 2013, 23:30

The forces generated from a tube are much higher than even a heavy wakeboarder. There isn't a single tower manufacturer, nor boat builder, that approves towing a tube from the tower.

Read these for specific references of damage.
WakeWorld Discussion Board: towing tube from tower

Bought a boat with a wakeboard tower- can I tow a tube?

Do you tow a tube with your tower?

Where do you tube from? - TeamTalk

ajstars · 13 February 2013, 23:46

Thanks, makes sense re the submarining. I have not used the tube yet so don't have experience of how it differs to waterskiing. Are we agreed that waterskiing is ok of the a frame though or should that really be off the transom too?

Phil M · 14 February 2013, 12:32

Quote:

Originally Posted by ajstars

Surely towing from the transom will load the transom more than towing from an a frame that's bolted to the transom and the hull?

Towing from the transom will directly load the transon its-self, and put a relatively small bending moment on the transom. If you tow from a standard A-frame, the distance from transom to the applied force if much greater and hence so is the bending moment. If you look at the a-frame photo shown you will eventually

see that the front legs reach as far forward as the frame is high. This distributes the load over the much larger area of boat and thus reduces the stress considerably.

Hope that makes sence!

Phil M

Festinghouse · 14 February 2013, 13:16

the frame acts as a great big lever

ajstars · 14 February 2013, 13:20

So should water skis also be towed from the transom?

Nick Hearne · 14 February 2013, 14:13

I have been towed water skiing from my little Avon SR4 with out any problem, but if you cut right outside the wake you can tell you are having an effect on the boat!
I have also towed our very large biscuit from it all ok but last summer I lost the riders put the boat in to a turn to pick them up the biscuit dug in to the water & with the leverage the Afram gives nearly flipped the boat! It went over 90% & spat me out kill cord cut engine & the boat righted it self, climed back in & all was ok , but will not be towing from the Afram again!
Bigger heavier boat & I think we would have been alright.

SimonCh · 14 February 2013, 17:18

Interesting points of view. Judging by the rigidity and mounting of the A-frame, I've never been overly concerned about its integrity, but I do take on board what is being said about the donut 'submarining' and have had the boat take a fair dip to one side because of it! Ill probably continue to tow skiers from the A-frame but perhaps not the donut! Time to splice up a bridle!

Peter_C · 14 February 2013, 17:40

Quote:

Originally Posted by ajstars

So should water skis also be towed from the transom?

The answer will always be it depends on the boat, and more importantly the tower. You don't want to be doing repairs on your boat because you ripped your tower right out of the boat do you? The safest will always be from the transom.

Post a picture of your tower from the side so we can see the mounts and the spread. Tell us how it is mounted to the boat. Are there large backing plates inside the hull? What is the hull thickness at the mount area? What size is the tower tubing? Is the design such that the forces are applied in the correct geometry? What material is the tower made out of?

FWIW I have seen specifically built towers fail at the welds just from wakeboarding off them. Scary thought on a boat filled with people.

Nick one upped everyone I know as I have never heard of the driver crashing while tubing.

So what is with everyone water skiing? Do you not know what a wakeboard is? Hardly anyone water skis in the USA anymore, as wakeboarding quickly took over as the water sport of choice. Not that I haven't tried, but doing 360's and flips on a water ski just isn't as much fun as on a wakeboard

Doug Stormforce · 17 February 2013, 00:44

Some A frames/RIBs are built for it. Certainly my XS700 is and a couple of previous RIBs were as well.

redthunder · 17 February 2013, 07:44

I wouldn't recommend it. I have had the upright on an a frames shear in the past from having a radar on a strutt on top. The whipping action caused the breakage. So a skier is going to be a lot more pressure.

ribraff · 17 February 2013, 09:08

It really does come down to the quality of the A frame itself and how well it is anchored on to the boat.
I installed a double A frame into a recent Searider refurb and it used for wake boarding from. The front sections are anchored through the hull with large spreader plates behind on the exterior.

There really isn't much point in towing off the A frame if you are using a donut or ski-ing. You're better off using the transom.