Rival 21 from batavento sailmakers brazil

Thanks for posting the drawing. Seems like a capable design. Sergio knows his job. His BateVento line is quite successful.

 

Finally I can work again on the boat !! As suggested by Gary Baigent, I manage to put down the weight of the first hull and built the second with the new specification. In this process of make it as light as possible a new question arise :
The boat is designed with 3 aluminium beams, the third in the bow seems to be a small aluminium pipe.
I saw a picture of this boat with a " second trampoline " on the bow but as my intention is to keep the bow empty (no trampoline or nets ) I start
To think that the aluminium pipe is unnecessary.....
Anybody can give me advise ?
Thank you

 

The bow tube is probably also designed as a compression strut, else the load of the forestay bridle will flex the hulls towards each other. The designer will know if its necessary or can be ommited. H

 

PS Did you ask the designer about using mdf as hull material ? I still can not see how that can be strong enough for a boat hull (having no fibres, only dust and glue ?). from the pictures it seems that your bulkheads are made of plywood. I'm a bit puzzled.
greetings, Hans

 

I understand everybody opinion about mdf and me too I am worried.....we will see...hopefully I do not upset anybody. I have been using wood+plywood glued with epoxy. The mdf too is glued with epoxy but the hull is finished with polyester resin over mdf and some fiber renforcements.
Mdf was my decision, email sended yesterday to the designer
Thank you Hans

 

Some updates on my first building.....

 

Here we are again !!!
I finally did a few sea trials and would like to share some impression. True wind range as low as 8 knots and as high as 18 ( based on my judgement....no anemometer )
I did noT use daggerboards becouse they are not yet ready. Did not use also the full boat potential ....did not fly the hull.
The boat is looking fast and sails also upwind even in this configuration. Off course difficult to tack....but still possible to be used.
All is looking reasonably good, except for the pins which are holding the shrouds. They are bending a little bit. They are 6 mm diameter but due to boat configuration as large as 50 mm and connected to a part as small as 14 mm so the effort is badly distributed. I can fix that but at this point my question is....how many kg of effort can I get on that shroud ?
At the moment my shrouds are 4 mm ( 900 kg ?? )
The boat is large 3,3 mt
The two hulls are 300 kg
Mast rudders daggerboard trampoline....50 kg ?
Two crew eventually at the trapeze 160 kg

Is my rig dangerous ???

 

Some pics

 

Does someone still have the pdf with that boat plans?