Randy Smyth's Trimaran

Patezfran,

One of the first articles I saw about Sissors said that the mast was an A-class but it was available because a mountain biker ran over it and broke it. The broken section was cut off and the remainder used for the boat.

Likewise the main hull was an A-class hull which was lengthened.

 

Thank you, upchurchmr, now I know why Randy used a shortened mast !
Not a design reason !!

Patrick

 

Ul 20

Doug,

Thank you for your interesting answer. Some drawings. would help to understand your design.
However I can't see the rationale behind the ultra light 20 Trimaran ! perhaps you can explain me :
If she is designed to lift the main hull, obviously it could be built even lighter with only two hulls, as a cat. In very light weather, as there is no diedral in the crossbeams it seems she has even more wetted area than a catamaran. The only advantage I can see is a tremendous righting moment upwind in high winds, if she can endure !
Cheers

Patrick

 

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Patrick, I thought the pictures would illustrate my concept better than drawings-oh well. I'm convinced that one of the main attributes of the trimaran is the ability to have an over square platform-particularly in 20' and under. Few designers appear to agree but few designers have produced a small tri that is faster than a performance beach cat-but it will happen.
As to the Ultralight 20, its claim to fame is its weight and so far I know of no race results-it will be interesting to watch.

 

I've been following some of the comments and observations about the Everglades Challenge and Randy Smythes Scissors on this thread.
In my opinion the EC challenge is a 300 mile 'endurance race' unlike any other, they have designed into the course several choke points typically to discourage larger boats, things like low bridges, narrow areas, and very shallow areas. They also have tailered their rules so you must carry 3-4 days of full supplies, tents, stoves, cooking supplies, 3-4 days of food and water,etc (as much as couple hundred lbs of stuff). The race rules also state that you are totally unsupported, and everything you launch with, you must finish with (ie.. things like beach wheels), plus the launch is from above the high water mark, and you must launch un-assisted, so this would make anything really big or heavy, very difficult to launch. I've been following the race for several years now, and have several friends who enter, unfortunately I never seem to have all my stuff together to actually enter. I'm also a little old for such a gruelling race. I do however always go to the launch and cheer my friends on and follow the race closely every year.
During the 2011 race I had my Tandem Island out in Sarasota Bay (I was not entered in the race, I was just out that day) and came across Scissors, I was amazed at how fast his boat was and was unable to keep pace with him. My TI is 21 ft (with bow sprit), with 265 sq ft of sail, even with my spinnaker deployed I couldn't keep up with scissors.

The Hobie Adventure series boats seem to be the preferred boat for this race, as there were 8 Hobie AI/TI series boats entered in the race this year, plus 2-3 additional home built AI/TI clones, using mostly Hobie rigging and parts (over 100 boats and kayaks in total). I have never seen more than 2-3 cats entered. Most every year we also see one or two Weta's, Triaks, and WR-17's entered, Not sure if any Weta's or Triaks have ever finished. This years conditions were pretty rough with 25-30 mph winds, and 5-6 ft seas at times during the dash down the coast. I admire all those guys doing this challenge, no matter what boat they use, just finishing is a huge accomplishment. Scissors appears to be custom designed and built just to do this race specifially (with Randy at the helm) so comparing Scissors to any other craft seems silly to me since the boat is a purpose built totally custom boat.
Just my 2 cents
Bob

 

What else are you going to compare Scissors to?

There were a bunch of "purpose built totally custom boats" on the starting line.

Lets see - A class main hull (modified) and a A class rig (modified)

Seems like a silly comment to me.

 

Before getting too twisted over Sizzors having too light scantlings, weighs too little, or has too little righting moment compared to beach cats that race and win Texel, you've got to consider the very unique goal that Sizzors was designed to achieve: circumnavigating the state of Florida. Things Sizzors needs to do that a typical Texel winning cat cannot do:

1) Traverse very shallow waters for possibly tens of miles (such as Florida Bay when the wind blows from the North, and several rivers).
2) A 40 mile overland portage, and several portages around rapids.
3) Go up and down narrow, shallow rivers with overhanging trees and branches for about a hundred miles.
4) Go up narrow channels and under low bridges to reach checkpoints.

Super low weight, super low resistance at low speeds, very good ergonomics for paddling, easy to drop and raise mast, and adjustable beam are technical enablers to meet those unusual objectives.

The boat and every part of the boat is remarkably light weight -- its almost surreal what Randy has done in his large workshop beneath his house.

As discussed before, the A class mast is a cut down damaged mast he got for almost nothing.

The A class hull used for the main hull (vaka) is dramatically cut down in freeboard, and extended aft, with nicely done structure, all carbon and foam. Its measurably lighter than a typical all carbon A class hull for a 75kg all up A class boat.

The amas are much, much smaller than an A class hull, much more like two surfboards, and weigh perhaps 10 lbs each.

The small diameter round carbon tubes (akas) that "scissor" fore and aft also have lines going through slits in the vaka, and the vertical uprights act structurally as dolphin strikers, so the akas are again dramatically lighter than A class catamaran cross beams while being strong enough for sailing loads. All the damage to such akas have occurred due to non-sailing forces, either while capsized in large breaking seas, or when run over by a powerboat.

Its an amazing boat!

Consider that when using the screecher and full main, the boat has well over one square foot of sail area per pound, crewed and fully loaded for a circumnavigation of Florida.

 

Maybe I misread some of the comments, I was only trying to point out that the EC challenge is not similar to many of the sanctioned Class racing events (a different type of race in my opinion). And you are correct, there are many totally custom boats always entered in the EC race (part of the attraction for me). I was just trying to point out that it appears to me that scissors appears to be designed specifically for the EC challenge, and there is little interest to conform to or fall into any strict class racing rules. No need to compare to anything else, the boat is what it is (unique).
Thats was my only point.
As a designer myself, my goals are to design my boat to take advantage of everything I can do (within the rules) to complete that race under any conditions following their class 6 rules (experimental electric/solar) in the fastest time possible. I am currently refitting my boat with soft wing sails, and an experimental solar/fuel cell electric propulsion system. Perhaps it will be ready in time for next years race.
Bob

 

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David, great comments-thanks. I just gotta ask: are you related to Randy?(!)
Scissor is an inspiration!

 

Small correction. West System is near Lake Huron in Bay City Michigan.

Its in Bay City