help with a catamaran
07-27-2009 | 10:31 AM
#1
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From: Cape Town, SOUTH AFRICA
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
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
07-28-2009 | 09:02 AM
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From: Auckland, NEW ZEALAND
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
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
07-28-2009 | 01:00 PM
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From: Cape Town, SOUTH AFRICA
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
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
07-29-2009 | 03:34 AM
#5
Senior Member
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
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
