RCU Forums - View Single Post - Mini40 multihulls future development route?!
Old 07-08-2010 | 12:31 AM
  #4  
egi1610
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From: Vienna, AUSTRIA
Default RE: Mini40 multihulls future development route?!

Hello Forum,
this is my first post (and most likely also my last one). I wanted to comment on this statement from Idealist a little:

<div style="border-bottom: medium none; text-align: left; border-left: medium none; background-color: transparent; color: #000000; overflow: hidden; border-top: medium none; border-right: medium none; text-decoration: none">"2. Eric Gielen (Aut 33) sails the last "Nightmare Mk.VII" , which I built together with him in 2007."

First of all Ernst, it is not in my interest to be publicly named in the internet without me knowing!

Secondly the statement "which I built together with him in 2007" is HIGHLY missleading. Ernst, remember, you did the hulls, to be precise the half hulls. This was indeed quite some work and it took us some time in the heat of your house to get them done, but this is far away from building a boat! This is the reason why I stopped to work with you. Your selfconfidence and your view of reality is so much blurred that I have to wonder.

Third, the boat sails well indeed, the floats are well sized, I can recommend using the free plans from Ernst and find it very generous of him to give them out for free! One thing one should not underestimate is the rigg. To me with my only 4 years of RC multhull experience the floats are important, the mainhull only needs to have enough volume, the main and key driver for a winning boat at this moment though is the power of the rigging. If one can control the rigg its half way down the race to win.

As such Idealist don't take it personal but you didn't build the boat with me, you made the hulls, everything else was then onwards after huge issues with your health and condition completed by me with the help of Karl.

Now with my knowledge of MKVII, what would I do different?
1) the sidehulls lack a little volume in the aft section, it sinks there when sailing on one hull, this does cost speed
2) don't just do straight beams, it is worth the efford to build curved beams as they NEVER touch water and thus never can drag, mine do (the advantage in this boat though was to be able to adjust the positioning continuesly to find out how much 'vorspur' (sorry don't know the english word for it) makes sense. Now that I know this I would switch to curved beams
3) the main hull was too soft, despite 2 layers of 160gr carbon the mainhull in the forsection at the mounting of the beam was/is to soft, I stiffened it after the facts with some carbon strings but it is still too soft, it would need some cross stiffness to not twist that much
4) mainhull is very unpractible to build up the boat, in a new design I would make the main boat in three halfs, left and right bottom, then build all the interior like mastfoot RC components, rudder etc and only then close it with a top half.
5) When the boat goes on one float it first pushes into the water and only then 'jumps' on one float. I have not found out the reason for this, only possible reason is that the mast position should potential be 2cm more to the back, this is the case in MKVIII plans so I am not sure if they would be directly comparable

Last comment: for all builders of MKVIII, I can only recommend to use glassfibre in a first round, use 2 layers of 160gr (std weight) and one outside layer of 50gr for the finish. this is stiff enough for Mini40 class and it safes you some money, once you have built the boat completely and are happy with the 'finetunings' it would need to fit your needs, you can build another set of hulls in carbon! before that its a waste of money to build in carbon.

So I wish that in Europr the Mini40 class and 2M continues to grow!
I also wish all dowloaded plans a happy build, the two build documents here are really helpfull for any newbie to get started right!

All the best
Eric alias egi1610

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