We ask top sailors and marine industry gurus to choose the coolest and most innovative yachts of our times. Paul Larsen nominates the International Moth
“There are so many boats out there that have cool aspects and yet remain horribly compromised or are no longer relevant. After a ridiculous amount of consideration (and excluding our own creations) I have to go for the foiling International Moth,” says the world’s fastest sailor , Paul Larsen.
“Like foiling or not, you can’t shoot the messenger! As a cool boat it stands on its own, and for what it has since inspired.
The International Moth has done more than any class to raise the profile of sailing hydrofoils. Photo: Thierry Martinez/Sea&Co
“The concept just works so well. Its performance and accessibility inspired sailors, backyard builders, designers and performance sailing in general.
“Buy a good one to race at your club or against the best of the best.
“This little foiler came to the local skiff/cat party and smacked all the old cool kids down. Things change when that happens.”
Make sure you check out our full list of Coolest Yachts.
Top speed: 30.7kn LOA: 3.4m Launched: 1971 Berths: 0 Price: €20,000 Adrenalin factor: 90%
Australian Paul Larsen is the world’s fastest sailor. In 2012 he sailed Vestas Sailrocket II to a sailing speed record of 65.45 knots .
His first taste of multihull speed was in the Eighties, delivering the 86ft Commodore Explorer to Japan with Skip Novak .
He competed in major ocean racing events before developing Sailrocket to make its record-breaking run.
Yachting World is the world’s leading magazine for bluewater cruisers and offshore sailors. Every month we have inspirational adventures and practical features to help you realise your sailing dreams. Build your knowledge with a subscription delivered to your door. See our latest offers and save at least 30% off the cover price.
Sail1Design
First Name*
Email Address*
February 13, 2015 by Sail1Design Editor Leave a Comment
Leave a reply cancel reply.
Your email address will not be published. Required fields are marked *
By submitting this form, you accept the Mollom privacy policy .
Browse the airwaves.
Great choice! Your favorites are temporarily saved for this session. Sign in to save them permanently, access them on any device, and receive relevant alerts.
Moth (International) is a 10 ′ 11 ″ / 3.4 m monohull sailboat designed by Open starting in 1928.
Auxilary power, accomodations, calculations.
The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.
Classic hull speed formula:
Hull Speed = 1.34 x √LWL
Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio .311 Hull Speed = Max Speed/Length ratio x √LWL
A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.
SA/D = SA ÷ (D ÷ 64) 2/3
A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.
Ballast / Displacement * 100
A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.
D/L = (D ÷ 2240) ÷ (0.01 x LWL)³
This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.
Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam 1.33 )
This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.
CSV = Beam ÷ ³√(D / 64)
Single handed development class that has always been at the cutting edge of performance racing dinghies. The MOTH, raced today (2015), at the top tier of competition is a ‘foiler’ with wings.
Embed this page on your own website by copying and pasting this code.
©2024 Sea Time Tech, LLC
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
The Worldwide Leader in Sailmaking
SAIL FINDER
SAILING GEAR
COLLECTIONS & COLLAB
WE ARE NORTH SAILS
ACTION SPORTS
Popular Search Terms
Organic cotton
Scuba fleece
Drawstring hood
Utility pocket
Stand collar
Sorry, no results for ""
Welcome aboard.
We want to make our emails as relevant as possible for you.
Interests saved
Something went wrong, please try again
Stay up to date with the latest North Sails news.
Receive a 10% discount code for your first apparel order. Excludes sails and SUP’s. See our Terms and Conditions .
Yes, I agree to the terms of use and privacy policy.
Dan neri explains how to get started sailing this foiler.
Compared to most dinghies, building the basic skill set for the Moth takes a long time. After about 40 hours of sailing the Moth, I can foil with confidence in all directions in the limited window of 8-14 knots of wind. I feel like I am close to executing a foiling jibe but have not connected two of them yet, and every tack is still an adventure with a surprise ending.
The experienced Moth sailors tell me that I am on a typical timeline. I was told that my decades of Laser sailing would help, but I don’t recognize a lot of cross over to the Laser. A skiff sailor will get there more quickly. Younger sailors probably learn faster than older sailors, but older sailors can afford to replace the broken parts! It all evens out.
Here are some lessons I have learned in my first nine months of Moth ownership that might help a fellow beginner.
First Assembly: Study the boat manufacturer’s assembly guide. Then get an experienced Moth sailor to help you. Plan on two full days. Take your time and you will break less parts.
Rigging: Watch the Nathan Outteridge tutorials. Then get a Moth sailor to help you the first time.
(And make sure to read How to Rig a Moth in 20 Steps )
Launching: Watch the Nathan Outteridge tutorials. Rig up in your yard and practice carrying the boat around in an area with no obstacles. You will find a balance point with the boom and mainsheet on your shoulder and the mast tip and wing bar both off the ground.
Flight setup: Get a Moth sailor to help you set the ride height control (see Flight Controls below). Pull the wand all the way up. Put the gearing in the middle. Then forget about the flight controls, and pretend it is a regular dinghy.
Balancing the Moth at low speed: Look for a day with 8-10 knots of steady breeze. Practice low riding while focusing on keeping the wings out of the water. Learn to tack at low speed. Hint: you can not scull with a Moth rudder. Try to not get stuck out on your Moth in less than six knots of wind. The Mach II is happier in reverse than in forward in very light wind.
Foiling: Watch the Nathan Outteridge tutorials. Look for a 10-12 knot day. Less than 10 knots makes taking off tricky. More than 12 knots feels like a hair-on-fire experience until you get some confidence.
Plan to sail for one hour with equal time spent swimming and foiling. Sail back and forth on a beam reach and enjoy the ride. Upwind and downwind can wait for another day; the first sensations of liftoff and controlled flight are the foundation that will keep you working up the steep and frustrating learning curve.
Turning downwind: This might be easier for sailors with skiff or catamaran backgrounds than it was for a lifetime Laser sailor, but the upwind-to-downwind transition is where I’ve had my most violent crashes. It is mostly a matter of starting with windward heel and then committing to the maneuver. The more breeze there is, the more aggressively you need to move through the transition zone. Waves make it more exciting. If you don’t go home with a few bruises, you probably did not progress. Get comfortable making the turn up and down in 10-12 knots before you try it in 14-16.
Foil Jibing: Watch the Nathan Outteridge tutorials. Then plan to crash a lot.
The maneuver has a few distinct steps; get moving at maximum speed with a slight windward heel, set your back foot on the hull and tuck your front foot, swing the tiller extension to the new wing bar, and lunge across and under the boom. Let the boat carve through the turn while getting your butt fully onto the new wing bar, then switch hands. While doing that make subtle steering adjustments, pushing the tiller slightly toward whichever wing bar is higher, to keep the boat under the rig. Simple.
Sail Trim: The Moth is extremely sensitive to sail trim, but for me, there was so much other stuff to deal with (balancing the boat in particular) that I took a set-it-and-forget-it approach at first. That was a mistake. Sail trim makes a huge difference in lighter wind by generating take-off speed (with a powered-up sail) and then by reducing drag and heeling moment once you are foiling (a flatter sail than you’d think). Again, the learning curve is steeper than other boats. To make sail trim adjustments, you have to learn to grab the right control lines (vang and cunningham) without looking down to find them, and then you have to pull two feet of line without upsetting the boat, while steering with the mainsheet in your tiller hand. Easier said than done.
There are four controls that dictate lift-off and ride height.
1.) Ride height adjustment: It’s critical to set the ride height adjustment barrel in the correct position. The ride height mechanism connects the wand to the main foil flap. The ride height range is set while still on land but after the boat is fully rigged, on its side. Once the range is set correctly, you can dial in a little more or less lift with the control line while sailing.
The ride height adjustment controls the position of the main horizontal foil flap. If the linkage is set with the rod too long (barrel screw opened up), the flap will be pulled up (no lift) and the boat will not take off. The opposite adjustment (barrel screw closed down) creates too much lift (a big gap between flap and vertical foil indicates the flap is pushed down, making a lot of camber) which will cause the boat to lift off and keep rising until the horizontal foil catches air (and you crash).
Experienced Moth sailors set the ride height by eye and it is a bit of a black art. If there are no expert Moth sailors available, adjust the barrel so that the flap and forward part of the foil form a fair curve when the wand is angled back about 45 degrees. Another gauge on the Mach 2 is to measure the gap between the flap and the vertical foil, which should be about 7mm with the wand all the way forward.
This shows the camber amount needed when you are up on the foils with just enough lift to keep you flying, with the wand hanging straight down and ticking the water.
Set up your ride height control line so that this neutral lift position is at the middle of the range of adjustment. If the breeze is very light, dial in more lift. If the breeze comes up, dial out some lift. As a newbie, it is easy to second-guess the ride height adjustment when in fact your technique is the problem, or to assume your technique is bad when in fact the ride height is way off. Get some help, so you can have confidence in this setting and focus on sailing.
2.) Gearing: Gearing comes into play once the boat is flying. Anthony Kotoun explains the function of the gearing control as “how much information do you want the wand to deliver to the flap.” If you find your boat is bouncing when passing over small surface waves, you have too much gearing (the flap is moving too much). If your boat is too floaty and slow to respond, the flap is not moving enough and you need to pull the gearing control down. Setting it in the middle is a pretty safe bet.
On my boat, the gearing control is the red line. If you follow it forward (towards the lower left of the photo) it connects to the black slider that is pushing down on the ride height adjusting barrel, along the curved arm. Most boats have the gearing led to both wing bars for adjustment on the fly. For now I leave it in the middle, so I have less lines to get tangled in!
The blue control line adjusts the shock cord that pulls the wand forward. In very light air, you want very little tension on the shock cord; as the breeze comes on, you want a little more. Worn shock cord makes the boat hard to control in windy conditions.
3.) Rudder angle: The rudder pin (the long pin that goes through both the upper and lower gudgeons) slides forward or aft in the rudder head, which changes the pitch, or angle of attack, of the foil at the bottom of the rudder. Changing the pin position and foil pitch controls the fore and aft flight trim. With the pin forward the rudder head moves aft, which in turn tips the foil up and creates more lift. More lift results in easier take off and more bow-down fore and aft trim. Moving the pin aft causes the rudder foil to sink and makes the boat fly with the bow higher than the stern. The pin position is adjusted by a big plastic screw inside the tiller, which is adjusted by twisting the tiller extension.
4.) Wand Length: The wand is telescoping with the length adjusted by a continuous-loop control line led to both wings. Shorten the wand for a lower fly height (better control but more drag and lower speed) and lengthen the wand to fly higher with greater righting moment and less drag (higher speed).
That probably seems like an awful lot to learn. It is, but it is also much easier to understand once you get your boat rigged up and laying on its side at the water’s edge. Pre-launch set up and check over is the only part of the Moth sailing game that you can learn while comfortably on land, without fear of crashing.
GET IN TOUCH
BROWSE ALL SAILS
Featured stories, offshore sailing guide, how to care for your foul weather gear, npl renew faq.
Damic Design specialises in design and manufacturing of Moths and Hydrofoils for the International Moth Class. While Moth sailing is our passion, our main objective is to offer the fastest, most developed and best built boats and foils on the market.
Our involvement in the class started in 2004, exposing us to the world of Moth hydrofoiling technology since the early days. The initial period was quite experimental, but also fun and educational as it allowed us to learn and develop our design ideas. We made a lot of foils in this phase with the most successful being the Macita that won the 2013 World Championship. While this foil is not on offer anymore, it certainly paved the way for the foils we make today.
In particular, the Swift range which consists of a number of sizes, each with different lift and control characteristics designed to ensure optimal performance over a wide range of sailing conditions. This range has now grown to include: Two rudders hydrofoils (Small and Medium), three mainfoils (Super Small, Small and Large) and our super thin HM carbon verticals.
The Swift Hydrofoil range is a refined product line with the foils now in their 3rd generation of improvements. We are constantly looking to make gains that we first test, and then bring into production.
What this means for you is that every product in the range is on trend and offers performance improvements for your boat without the need to upgrade the entire platform. While this range is sold with our Swift Moths, it is also available to Bieker, Exocet and Mach 2 owners that are looking for a fast upgrade option. Our foils placed 7 out of the top 10 at Perth Worlds, won 2023 NSW and Australian Nationals and also got 2nd in the Waymouth Pre-Worlds regatta. Furthermore, all Damic Design foils are made in Australia and are constructed from solid carbon fibre, from market leading supplier, Toray. While this increases production costs we believe it is warranted as it insures superior quality and perfomance on what we consider as the most important part of the boat. We are also proud to be the only foil manufacturer that is solely focused on foil development and directly involved in design, testing and manufacturing of all of our products. That means that every foil that leaves our workshop has been hand finished by the designer and Moth sailor that truly understands the product and what is required to make it go fast!
Swift Mainfoils
Our latest hydrofoil, specifically designed for light sailors or as a strong wind foil. It features an innovative tip and bulb design that are optimised for reducing drag when going fast.
$3,350 AUD + GST
The ultimate all round medium wind foil, that has been winning regattas since the initial release. It is known for having great control features with a very wide performance window.
Excellent high lift foil that can be carried up range thanks to its thin section and very efficient profile. This foil is a proven race winner and a must for heavy sailors or light wind venues.
Swift Rudderfoils
The Small rudder is based on the same theory as our Medium. It is a high aspect low drag shape designed to minimise drag and maximise lift offering great glide though ability for ease of foil tacking. Unlike other small rudders, ours still makes foil tacking a breeze while being tiny in size and super fast.
$2,200 AUD + GST
Our Medium rudder is a well proven design that is a result of many years of development. Its short cord makes it very low drag however it generates plenty of lift thanks to its high aspect ratio. This foil will help make your foiling tacks easy and repeatable. $2,200 AUD + GST
Swift Verticals
The v3 is our latest design to date. It further improves on the original v1/v2 designs with changes in the bottom 1/4 of the section. It is designed to be on the absolute limit of the materials to insure the ultimate performance from reduction in drag coefficient. It also includes a number of design features that combat the “all too common” rudder wash out problems. Made from pre/preg solid High Modulus carbon fibre construction, it is thermally stable and ultra stiff.
$4,100 AUD + GST
This is the thinnest main vertical on the market which offers significant reduction in drag by simply being smaller to reducing skin friction and displacement. Made from solid High Modulus carbon fibre construction, it is thermally stable and ultra stiff. Includes pushrod and bellcrank kit.
$4,500 AUD + GST
These angle of attack measuring templates, are designed to fit our range of Swift main and rudder hydrofoils. With the help of this device, you will be able to determine the all important foil angle relative to waterline. $45 AUD + GST
Tailor made to suit Swift HM Main verticals and HM Rudder Verticals. These premium quality covers are Australian made using quality Dimension Polyant sailcloth. They features marine canvas outer skin and felt lining inside. $120 AUD + GST
Suitable for Swift Super Small, Small and Large horizontal hydrofoils. These premium quality covers are Australian made using quality Dimension Polyant sailcloth. They features marine canvas outer skin, felt lining inside and Velcro closure to protect the trailing edges. $110 AUD + GST
It is not easy to find your first moth. The best way is to get in contact with your local moth sailors. Basically you get what you pay for. There are a lot of second hand boats on the market but there is also a growing numbers of moth builders.
Show All Categories
Popular Brands
More >>
Featured Companies
Year: | 2005 |
Length: | 11' |
Location: | West Sussex UK |
Price: | £2,000 |
Length: | 11' |
Location: | Surrey UK |
Price: | £2,750 |
Year: | 2014 |
Length: | 3.3m |
Location: | Kent UK |
Price: | £2,400 |
Year: | 2014 |
Length: | 11' |
Location: | Oxfordshire UK |
Price: | £4,995 |
Year: | 2011 |
Length: | 4m |
Location: | London UK |
Price: | £4,000 |
Caveat Emptor. Verify before you buy.
Your use of this website constitutes your acceptance of the Apollo Duck User Agreement
We use cookies to enhance the functionality of this service. Read more in our Privacy & Cookie Policy .
Apollo Duck is a Registered Trademark | Copyright Notice | Advertising Terms & Conditions
162.248.224.4
IMAGES
VIDEO
COMMENTS
As a development class, the International Moth has been a hotbed of foiling innovations. Matthew Sheahan reports on a new accessible one-design version
The Moth is a small development class of sailing dinghy. Originally a small, fast home-built sailing boat designed to plane, since 2000 it has become an expensive and largely commercially produced boat designed to hydroplane on foils though many are still built at home, typically at much lower cost. The pre-hydrofoil design Moths are still ...
North Sails 14.5K subscribers 75K views 2 years ago #moth #foiling #foil ...more
About the Boat The international Moth Class is the fastest one Person Dinghy in the World.
Joining the US Moth Class's Facebook group is the best way to see what's going on and get involved with the class. Stay up to date with regattas, boat building projects, and general moth froth!
INTERNATIONAL MOTH SPEED GUIDE Moth Dinghy expert Rob Greenhalgh introduces this extraordinary singlehanded foiling dinghy and describes the keys to sailing one fast.
Following his win at Lake Garda, 2012 World Moth Champion, Josh McKnight then set an outstanding top speed and ten second average on his Mach2. It goes to show the Mach2 / KA Sail is a killer combination! 31.5.
Classic Moth Boats are a class of small fast singlehanded racing sailboats that originated in the US in 1929 by Joel Van Sant in Elizabeth City, NC. The Classic Moth is a monohull development class using a modified version of the International Moth rule in effect pre 1969. With an eleven foot over-all length, a maximum beam of 60 inches, a ...
We ask top sailors and marine industry gurus to choose the coolest and most innovative yachts of our times.Paul Larsen nominates the International Moth
Learn about the Moth class in World Sailing, a unique sailing vessel known for its hydrofoil technology and high-speed capabilities.
The moth class association that had originated in the US was now truly an international organization. Being a development class, the moth has evolved from a hull in the 1930's that could best be described as a heavy, narrow scow or a blunt nosed skiff, (weighing about 50 kg) to today's remarkable foilers with hull weights of under 10 kg,.
The Boat: Evolution. The original International Moth was the combination of two similar boats from opposite sides of the world. In the late 1920s in Australia, Len Morris built a cat-rigged scow to sail at a resort near Melbourne. Flat bottomed and hard chined, the boat was 11 feet long and carried 80 square feet of sail area.
Single handed development class that has always been at the cutting edge of performance racing dinghies. The MOTH, raced today (2015), at the top tier of competition is a 'foiler' with wings. Hull weight: Unrestricted. General weight range 10-20 kg / 22-44 lbs. Rigged weight: As little as 26 kg / 57.32 lbs. Optimum skipper […]
And now for something completely different - The International Moth story. Over the last year or so, there have been a couple of key themes that have kept reoccurring in the articles that I have written for you. One is the fascinating topic of innovation and how it has driven - and been driven by - dinghy development.
Experience championship-level performance with the new Helix Moth Sail - trusted by the world's best, including 2022 Moth Worlds Champion Dylan Scott. Packed...
Moth (International) is a 10′ 11″ / 3.4 m monohull sailboat designed by Open starting in 1928.
HOW TO BUILD YOUR MOTH SKILLS Dan Neri Explains How To Get Started Sailing this Foiler Compared to most dinghies, building the basic skill set for the Moth takes a long time. After about 40 hours of sailing the Moth, I can foil with confidence in all directions in the limited window of 8-14 knots of wind. I feel like I
Damic Design specialises in design and manufacturing of Moths and Hydrofoils for the International Moth Class. While Moth sailing is our passion, our main objective is to offer the fastest, most developed and best built boats and foils on the market.
10. New Zealand 'R' Class skiff. In New Zealand they love their skiff sailing, and development classes like the doublehanded 'R' Class are prime for new features. The 'R' Class started its project to get the fleet foiling back in 2008 and now there are a clutch of boats racing.
Since building my boats I have had many questions about how I went about certain areas of my builds. Below are the ways that I have built my last two International Moths.
Classic Moth Boats are a class of small fast singlehanded racing sailboats that originated in the US in 1929 by Joel Van Sant in Elizabeth City, NC. The Classic Moth is a monohull development class...
Get a Moth It is not easy to find your first moth. The best way is to get in contact with your local moth sailors. Basically you get what you pay for. There are a lot of second hand boats on the market but there is also a growing numbers of moth builders.
International Moth believed to be a Mistress mk 3 from around 2005. All Carbon, hull sandwich construction, good paint, anti- slip, trampolines and control lines.