PDA

View Full Version : Making a wakeless launch out of an old HobieCat?!



Wade Lippman
10-25-2010, 6:01 PM
Several years ago I was visiting Princeton with my son, and the crew coach showed me a wakeless launch they had made out of an old HobieCat. Since then I have been searching for a really cheap old hobie and finally found one.
Now I just have to make a launch out of it.

I expect it has been done many times before, and don't want to reinvent the wheel. If anyone can steer me to some "directions" I would be most grateful.

Jim Creech
10-27-2010, 11:22 AM
Check Out Sandbarhopper Boats!

Carl Carew
10-28-2010, 6:46 AM
http://www.catsailor.com/wild_thang.html

here is a link that shows pictures of a commercial conversion hope it is some help

Carl

Wade Lippman
10-28-2010, 1:05 PM
http://www.catsailor.com/wild_thang.html

here is a link that shows pictures of a commercial conversion hope it is some help

Carl

Good lead, but the email and telephone are both dead.
I have posted on the associated forum, so that might help. thanks

Roderick Gentry
04-18-2011, 6:16 PM
I built a boat like that about 15 years ago, but I built it from scratch (and for fishing), which in a lot of ways is actually easier. I used to row "at" Princeton, but back then they didn't use displacement craft as the chase boats. I googled it, but only got a picture that showed half the boat from above. It seemed as though their float was pretty much sunk, or like the one in the link above sunk to the rear. Stuff like this normally works better if everything is flowed together, so that common elements exist that save weight/cost/building time. This is possibly harder to do with existing floats with hard point load path, but obviously doable.

Which brings me to point one. We need pics of your floats, and what the hard points are. Are we talking vertical pipes?

Second point, what kind of structure are you going for? Do you want the same banquet approach they used, or an open deck?

Cats in sailing mode have the advantage of reducing the weight that would be required in a ballasted boat. In a motor situation there are weight savings from the form, but also the weight of large areas where walking loads need to be structured. One of the key issues will be the overall beam of the boat, and/or new structure. One needs to look at any trailer when considering this. to be sure you will have the required clearances. Beam figures into stability, but stability will likely be sufficient. Beam will affect cost and weight a lot. To make this work one needs to use some kind of light construction, not just a picnic table set in concrete around the hard points. :)

While it isn't necessary, it sure helps to have a displacement figure for the Hobie hull. There are a number of way of getting this, but online specs would be the easiest. You want to know what the immersion displacement is and maybe about mid way down, and at the waterline.


I think as you look through this you may appreciate how many decisions will be affected by the fact you are using Hobie hulls, and given how little work is required to build these hulls, there is something to be said for rethinking that, but not to worry for now. Get some numbers on paper, weight of hulls weight of people, weight of systems, displacement of hulls, and center of Buoyancy. And you can make those decisions later.