rear beam

[paul anderson]

g,day

i have been looking at ways to make a beam for the tramps of my tiki 26.now i woud like to build it out of timber or other materials.i know alot of people have used ally poles and spars,any thoughts?

cheers paul.

[Russell and Janet Puryear]

I'm pondering the same.  I've been thinking of and I shape made from 3/4 x 3 1/2" bottom and vertical and a 3/4 x 5 1/2" top for mounting a wind vane.  Here that should provide a lightweight and inexpensive system.  After I build it I'll do a stress test by standing in the middle.  I could sit and do the calculations, but it hardly seems worth it.  Imperial sizes, I apologize to the rest of the world that uses a rational measurement system.

[clif high]

any work such as this that i undertake now, i coat the work in resin and either glass or carbon fiber, and then vacuum bag the critter with heavy plastic and shop vac as the vacuum source. You can tie off a shop vac bagging system with twist ties and bits of rope around the throat plastic of the sack. It produces marvelous results, quickly, eliminates out gassing issues, and provides for an even saturation of the material with resin (if done correctly). Not rocket science and good results can be obtained with just a trial or two. Just in the process of installing some collars, for dagger board foils, and rudder foils on my umiak trimaran and i will post pictures of these first carbon fiber pieces if everyone agrees not to laugh.

 

Going to vacuum bag every bit of work on my tiki 21 restoration and thinking now of how to vacuum bag the production of the tiki 38 hulls....now i get the appeal of constant camber construction techniques using vacuum bagged panels.  In any case, this technique is what i plan for beaming the tiki 21.

 

[kim whitmyre]

Paul, Scott Williams aft netting beam is wood and somewhat triangular. This does provide a nice surface for attachments. I have a 2 .25"/57mm OD, .25"/6.3mm wall aluminum pipe: very strong, no deflection when I sit on it at all. Trickier to attach things to, unless it's by lashing.

[paul anderson]

thankyou for the replies all,yes kim i like scotts triangular beam for attaching bits to.i think i would make them triangular and then on the ends circular for better lashing properties.could one make this beam with a combination of timber and foam?

[Duncan Clausen]

Hi Paul, here is my 2 cents worth, for what it is worth! I would either go for a square/rectangular box section or a "I" section for the rear beam as these will be most efficient for the loading conditions, which are both vertical and horizontal. I think that the "I" beam is the most simple, has no internal void to worry about, has a nice flange (bottom) to lace a trampoline to and the top flange is a nice flat surface to mount wind vanes etc. A flat bottomed beam also has less tendency to rotate. I would also make a hole in the web under the lasing so that a few frapping turns can be made, the lashings would go through holes, either side of the beam, in the stem post or beam mounting block (if forward of stern post - see Tsunamichaser), thus eliminating the need for a lashing block. I hope this makes sense to you. Simple is good!