???Strap Two Hobies Together???

We have two Adventures. Great Boats!
Our river is wide-open and it has occurred to me that it might be fun to strap our boats together in some fashion. Easier to chat - more stability - equal pace, (we also have a tandem bike and like the comraderie). Brings up a few questions:

Would there be adequate clearance under the water so that turbofins would not conflict? If they might touch I suppose the boats could be staggered slightly.

I wonder if there would be any turbulence or quasi-cavitation issues even if they didn't touch?

What would be the best way to fasten the boats together? Seems it might be best to separate by a few inches with a buffer of some kind to avoic hulls rubbing together.

Has anybody done it? Somebody must have....

_________________
Steve G. Garrison

my wife and I use the paddle bungee to lash our boats togeater, the bungi does on my screw head and vise versa, have not have any problems, we are usually in and Revolution and a Sport. Should work with adventures, if the bungee breaks its a easy and cheap fix.

_________________
Brad Stephens
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Here's something you might try:

Using 1/2" pvc anchored into your mast mounts, run a link between the two boats like this:


You can connect two halves of this link with some tubing, hose or cable (whatever may fit snugly over or inside the tubing) to provide one or two flex points.


If you try it, let us know how it works out!

1. Using the paddle bungees sounds pretty easy and we'll give that a try when we get some warmer weather. We have a 2006 and a very recent 2007. Seems to me the 07 went to a different bungee system for the paddle. I'm not near it right now but will look and see if feasible.

2. The pvc system seems ingenious and not too difficult. Two questions about that....
A. Why is a "flex point" necessary?

B. Assuming it's a good thing - how would you best secure the hose or cable inside the pvc pipe?

_________________
Steve G. Garrison

Kayak attached to kayak = kayakamaran

_________________
James
86' Redline Hobie 16
Sail # 76909

Suppose a boat wake is approaching your "yakamaran" from one side. One hull may tilt to port while the other tilts to starboard. Without the ability to flex, your link might snap or you might overstress the mast tube. So this allows for independent articulation (pitch, yaw and roll) of both hulls.


Epoxy or pvc glue, screw, tape, hose clamps, tube expansion -- any of these, depending on what your flex point is made of and how it fits on your pvc. If it's snug enough, friction may hold it in place. Just play it by ear!. My picture was to show the concept only -- I would try to find something to slip over the pvc as a first choice. If there is nothing suitable laying around the house, you might find a good selection of tubing at your local auto (or medical) supply store (take a sample along for a trial fit). You can also change pvc sizes by use of adapters and connectors at your flex point if necessary. One possibility for example might be to build an 8 or 10" mini-garden hose screwed into a pvc adapter glued onto your pvc pipes.

Once you try one out, you may well end up refining the design or deciding it doesn't work as expected. That's half the fun of it.

BTW, I would use schedule 40 for the link and sched. 80 for the mast receiver inserts (approximate full length of the tube).

3+ years ago, before I got 2 Islands I did rig Sport & Outback in tandem cat fashion; boats were seperated by only 2" and was driven by 1 standard sail & 2 mirage drives. Used 3/4" pvc pipe strengthened with internal 1/2" electrical metal conduit inside the horizontals. Worked Great. Frames never got bolted to the hull but used the scupper holes and front mast holes. One could line up the 2 boats and plug in & bungie the frames in 3 mins.

The ends of the 3/4" PVC pipes that plug into the scupper holes are fashioned with a 1/2" PVC cap and small 1" long 1/2" PVC pipe sanded to fit inside 3/4" pipe. Keeps end of PVC smooth to avoid damaging the scupper holes. Also keeps water out of rear frame. Lengths are adjusted to terminate just at the bottom of the hull. Too long= drag, but too short is no good either.

The trick is to get the lengths correct so that both boats are parallel with any error favoring toe-in.

The frames have been adjusted to compensate for the differnce in height between gunnel to scupper holes of the 2 different kayaks. That is why they appear non-symmetrical.



View of frames



Connected to outback rear. Yes. thats a small loop of cord looped thru the scupper holes under the hull. The cord can remain in place all the time and allow you to bungie on the frames whenever you need.

Also notice the frame lenght fully contacts both gunnels - similar to the sidekick



Outback front w/ sail mast




The Sport gets plugged into the frame the same way - except instead of a mast & sail in front I use a 14" 1/2" PVC as a dummy pin. One could use 2 sails I suppose.

Pic below - you have to imagine the sport being attached to the left of the Outback. Sorry no pics of both boats together or under sail.

Notice the 1/2" PVC dummy pin. It is not glued to the frame, but bungies in to sail connector on hull. So the 2 ends of the front frame terminate in a "T" shaped PVC fitting. The sail can be used on either boat, or 2 sails, or no sail (use 2 dummy pins)



Used it about a dozen times. Me in Outback, wife in Sport. Boats seem to roll as one and sail as one. Not suggested for any wild weather. I could sail in higher winds w/o fear of tipping over. Wife could go sailing w/o having to control the sail. Just coordinate your rudder use and your set.