Marblehead Racing - Page 25 - RC Groups
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Aug 16, 2012, 10:45 PM
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Here is CO the light skinny 80's boats do well in the light drifting conditions. Once the wind is up like in SD (8 to 12) they just dont make VMG like the newer boats.
The thing is in the light air being faster or have slightly higher pointing dont matter as you never stay on one tack long enough. The heavier boats, 10 lb + suffer in the light drift conditions against the lighter 8 lb narrow boats (skinny, hot dog). The viper does well in light drift with a light bulb and swing rig.
Last edited by slotracer577; Aug 16, 2012 at 11:41 PM.
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Aug 16, 2012, 11:17 PM
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The lighter the conditions, the quicker the sleek keels can be, because they carry momentum... Like the Madcap/Cheerio.
The "newer" boats have less momentum, and are designed more for acceleration.

Think of it this way:
With the Madcap it takes a LONG time to get up to hull speed. Then, it takes a LONG time to slow down (if you make a mistake)
Think of hitting the brakes on a tractor-trailer.

With the Skapel, It is VERY quick to get to hull speed. It ls also VERY quick to stop.
Think of hitting the brakes on a porche 911

Heck, I bet if you built a Madcap or a Cheerio with modern construction techniques (out of Kevlar) you could potentially rock a Skapel to sleep in the right conditions.
Who wants to take on that experiment?

It's the M class you know, you can do whatever you feel like.
Last edited by breakwater; Aug 16, 2012 at 11:24 PM.
Aug 16, 2012, 11:59 PM
Registered User
My idea was to build a light Kethman Delta hull with modern foils and rigs!!

There are a few old lines plans out there that could make good modern conversions.

I am in the process of tuning a hard chine 10 rater designed in 1980 by Vic Smeed called Spook, bought the plans from Model Hobby Store along with Vic Smeeds Genie Marblehead.
It is now narrower, lighter at 5.6kg, 80" long with 1465mm waterline. Loves a breeze! Carries A rig very well.
When I was a youngster I lusted after this boat, so decided to build one 32 years later.
Aug 17, 2012, 12:45 AM
Love RC Yachts!!!
What I love about M's is that with all the variations in hull design, foils and rigs, they all race very closely.

We have seen that money doesn't really buy speed, Skalpels included.

Here in OZ, I've never really seen the Skalpels excel in light airs because of their engineering (which is fabulous). Rather it has been light bulbs at 2.8kg that helped them. I've only played with one very briefly, but I found them quite straight forward to setup, namely they seem to like a straight leech on the main, and about a 40-50mm slot on the jib, and away it went. Tuning the 'butterfly' system for the jib can be tricky though.......

We are fortunate down here that we have a number of different designs racing, mainly homegrown, and UK designs.Like Mopar68, I have a newly acquired Fuzzy Logic, with conventional rigs. Before that I raced a Scourge design, that was particularly slippery in light airs, with a 4.6kg dispalcement, but held its own in a breeze too.

With the worlds approaching, I think we will see more developments, namely chine boats now. There is a new design here that is best described as an A-Cat bow section, mated to a chine/ tumblehome stern section. Very radical, and cool looking. We are also playing with pre bent high modulus carbon tubes for rigs too, so fun and games here in OZ!!!!!

I just love racing these boats!!!!

Aug 17, 2012, 05:04 AM
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NZL756's Avatar
I'm running a home built astra (Bantock design) running 3.5kg of lead, all up sailing weight of 4.94kg A rigged.
Aug 17, 2012, 04:17 PM
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Dick L.'s Avatar
Originally Posted by bigpat
There is a new design here that is best described as an A-Cat bow section, mated to a chine/ tumblehome stern section. Very radical, and cool looking.
This general M Class plan has been around since last summer (2011) so the reverse bow (popular in A Class catamarans has been out for about the last 5-6 years) and was quickly adopted by C Class cats and of course the AC Cats.

The series of boats and plans was done by Claudio out of Nice, France. He is a great contributor to the RCSAILING.NET web site.

Aug 19, 2012, 09:50 PM
Love RC Yachts!!!
Looks cool Dick!
Any sections of it available too?

The local boat here appears to be straighter in planform than that design. I'll try to get some pics soon.


Aug 20, 2012, 11:44 AM
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Dick L.'s Avatar
BigPat -

yes - on that forum topic, he has provided several different designs, and does a superb job of offering a lot of the technical specific data and locations. (CLR, CoB, Weights, measurements, and cross section templates for the hull). Please visit the suggested web forum site, and just search on the word "AZUR" and you will find a variety of lines, displacements, sideview profiles, etc. Claudio also has provided a complete post on making a "tool" to build your own sails. He is a great contributor to the sport of r/c sailing.

Also has provided building plans/blog of the much larger IACC boats if that is the style that interests you.
Aug 20, 2012, 05:39 PM
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thorsail's Avatar

2012 Marblehead Nats -San Diego

HMS2007 Scoring v2.2r - 13Sep2008 - Promo = 4
Event 2012 USA Marblehead National
Date(s) August 1st 2012
Host Club San Diego Argonauts 2012 Race Week

Position Skipper Sail # Club/City Hull Freq Score
8 8 0 8 8
1 Eric Arndt 13 Fairfax-CA 2.4 14.0
2 Dick Carver 02 La Habra-CA 69 20.0
3 John Castelli 17 Yorba Linda 76 20.2
4 Robert Fisher 97 Irvine-CA 64 42.0
5 Bruce Andersen 16 Boise-ID 2.4 47.0
6 Dirk Brewer 44 Tempe-AZ 2.4 63.0
7 Mike Eldred 39 Alpine-CA 2.4 64.0
8 John Fisher 49 Elbert-CO 2.4 66.0
Aug 20, 2012, 06:56 PM
Registered User

What designs were sailing at the US Nationals??
Aug 20, 2012, 09:51 PM
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1 through 4 were skalpels. 6 was a Bantock Monarch, 8 was a JT Pixel. The other two I think were the same design, but I dont know for sure. I didnt catch the design. Both 7 and 8 were DNF. I sailed the Pixel and the DNF was due to changes I made to the rigging, not the design.

Aug 23, 2012, 01:10 PM
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Nice article in the AMYA quarterly magazine by the class secretary.
But someone please explain to me what it had to do with the Marblehead Class?
Aug 25, 2012, 08:14 PM
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It was a good article for people who are beginning to sail. OK it was not about the latest rocket science but it was about model sailboats and last time I looked Marbleheads are model sailboats.
Aug 25, 2012, 09:09 PM
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Originally Posted by DGN
It was a good article for people who are beginning to sail. OK it was not about the latest rocket science but it was about model sailboats and last time I looked Marbleheads are model sailboats.

There are 2 pages of rules descriptions on pages 26 & 27, along with 3 more pages on tactics in the magazine on pages 29,30 & 31.

It's not the Marblehead's job to talk about the rules of racing. It's the Marblehead's job to promote and communicate the health of the class.

Just sayin'
Why are we getting off topic?

I've got an idea where to hold the Marblehead class Nationals if we're looking for a hosing club....

Sorry for another M misconception.
The M class is not entirely about rocket science. (Visual assistance attached)
Aug 25, 2012, 09:29 PM
Registered User
Originally Posted by breakwater
(Visual assistance attached)
Wow, look at the ditch that thing is digging!!!

Is it an M or a VM?

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