help with a catamaran
 

Hi all.
I have just built a catamaran hull 120cm by 54cm and jusr realised that I have no idea how high to make the mast and what size the rudders and skegs should be.
Please could some one help.

Kind regards

RE: help with a catamaran
 

Hi Chf,

I am thinking that you would be better with a beam around 80cm for a 1.2mt cat...but I have not built a RC cat myself so am no expert.

I did spend a fair amount of time investigating building a 1.2mt cat though.

I would have thought mast height between 1.6-1.8 mt would work for you..(at 54cm beam).

Rudders and fins ...hmmmnnn..well you could probably use rudders from a IOM mono ( if you are running twin rudders) otherwise if you are using a centre mount rudder and centreboard (and I have seen this work very well on a few 1.2mt cats) then you probably need rudder around 250cm deep and centreboard 350mm deep. Both would need to be around 6cm wide. As for the thickness , that is anyones guess??..but probably between 5-8mm thick at widest point.

Sorry I cannot give you better info..there are much more experienced cat builders out there who could give you wiser advise I am sure..good luck.

Gary

RE: help with a catamaran
 

Hi dreamwakes
Thanks for the advice.
I built it from glass, so it is quite heavy. I don't know if that will make a differance. The disign is from a old glass demmo I found. I just assumed that it was in proportion.
I think that I will try a narrow 1.8m sail and the dual rudder and centreboard. I am not fammiliar with an IOM, will probably make them myself out of perspex, it worked well on a small fishing skip type thing.

This is a great start.
Thanks again

RE: help with a catamaran
 

[link=http://www.rc-sailboats.com/plans.htm]Link - Catamaran Plans[/link]

http://www.rc-sailboats.com/images/plans/c6.jpg

RE: help with a catamaran
 

Chf

If you croll down on this site, you can see three pics of a 120cm cat how I would build it:
http://www.rc-network.de/forum/showt...=133541&page=8

It´s the boat with grey hulls.
about 80 cm wide, but only ONE Rudder and ONE centerboard in the centerline of the cat.

Otherwise you don´t have enough transversal stability to sail the cat without crew weight -
and if the boat had two rudders and centerboards, one has allway to be pushed around the other.
This caused a lot of frustration and aimless discussions in the past.

Mast height 180 cm for 0.9 m2 will be ok!

Idealist