Mark Saunders took an old Europe dinghy hull, gutted it and attempted to rebuild the boat so that she would weigh in at the CMBA minimum weight limit of 75 lb as opposed to the International Europe Dinghy Union's minimum hull weight of 99 lb. After racing a Mistral for several years, Mark appreciated that a stock Europe is a better behaved boat compared to the Mistral design and in some conditions a Europe can give the faster Mistral pilots a spot of bother. He reasoned a reduced weight Europe, equipped with spars and blades lighter than the stock items, would be even more troubling to the Mistral skippers. Mark just barely completed the boat in time for this year's
Classic Moth Mid-Winter Regatta and the boat had a few teething problems. Even so, Mark finished 3rd overall. The official weigh in for this boat will happen at the Nationals in September, but Mark thinks he managed to remove about 15 of the offending 24 lb from the hull. With the lighter equipment he no doubt significantly reduced the overall weight of the boat in all up race ready state. It will be interesting to see how this boat goes as he develops her during this year's racing season. The photos that follow are a combination of mine and Lennie Parker's, taken at last weekend's regatta.
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| Mark in the process of rigging the boat for the first time. He removed the fiberglass decks, side tanks and most of the daggerboard trunk during the reconstruction of this boat. The cockpit layout, in general, follows the design of Joe Bousquet first seen on Joe's Mistral Try-Umph. |
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| The roll tanks for the side decks, made of 3 mm marine ply, are reinforced with a layer of carbon fiber cloth on the under side of the panel to provide adequate stiffness to take the pounding of the skipper's weight. The fore and aft decks are not carbon clad in order to save weight. |
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| Mark does lovely work. The cockpit sole also received a layer of carbon cloth to provide stiffness in the stomping area of the cockpit. The carbon fiber cloth is lighter than the original structure and prevents the hull from "oil canning". The well deck and bulkhead also introduce a bit of stiffness and minimize the amount of open cockpit space if water comes over the bow. Mark decided on an aft bridle traveler system so that he could minimize the weight of the carbon fiber boom he plans to use in the future. The aft bridle also saves weight compared with the teak center traveler horse and hardware it replaces. |
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| The sail shape controls are led to the aft edge of the foredeck rather than below decks as is the typical Europe dinghy practice. The recessed area in the center of the main bulkhead is the compass binnacle. |
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| The inhaul is a simple 2:1 system led to a clam cleat on the boom. Mark used a boom made out of Dwyer DM-1 section for this regatta as his lighter carbon boom wasn't finished in time. DM-1 weighs about a half pound per foot. The eventual carbon fiber replacement will weigh half of that. Mark's mast was supplied by Ted Van Dusen and is much lighter than my IEDU legal carbon mast. |
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| The mast tube follows the oval arrangement recently seen on other Classic Moths. Note the clever carbon tab which provides a place to locate the line for the vang attachment. Carbon tubes do not like having holes drilled in them for fasteners. Such holes are often the origin of dramatic failures of carbon fiber structures. |
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| Here we see a small section of the yet to be used carbon boom. The added tab, also fashioned from carbon cloth provides multiple attachment points for the vang. The tube itself started life as the top section of a windsurfer mast. |
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| This detail shot shows the tab which Mark fabricated and bonded to the leading face of the mast as an attachment point for the spectra bow stay. This again avoids drilling holes to attach the typical hounds fitting. Although the mast is designed to be free standing, like the stock Europe mast, the bow stay, which runs to a simple block and tackle system on the foredeck, provides "on the fly" mast rake adjustability, in concert with the oval mast tube. My stock Europe dinghy's mast rake can also be adjusted out on the water, but to do so requires the boat to be hove to into the wind and the skipper to reach though an inspection port, inside the bow compartment to turn a screw. This can be done in between races, but is something that can't be accomplished while actually sailing. |
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| Mark also made the cheeks for the rudder stock as light as possible. The rudder blade is currently a stock laser item which will no doubt soon be replaced by a lighter blade with a more efficient shape. Not seen in any of these photos is the gybing daggerboard which Mark used during the regatta. As mentioned in the previously post, Mark slaved away on that item at the yacht club in order to get it to fit the trunk! Hopefully I'll be able to document that blade at a future regatta. |
I see a lip (overhang) on the aft end of the deck. Any practical reason for that?
ReplyDeleteNo, I can't think of any advantage. He probably just liked the way it looks or else didn't get around to making it flush before the regatta. This boat barely got complete enough to race in time and is very much a work in progress.
ReplyDeleteGorgeous woodwork. This boat continues to inspire me...
ReplyDeleteGreat pictures and commentary! I'm most interested in the other offshoot Moth species in various parts of the world and how things have evolved, or not evolved as the case may be. As I have not yet read Mark's original blog on the restoration, I presume he achieved the minimum weight of 75 lb? I can see lots of opportunity to shed more weight if needed, but there's not really any point if the target has already been achieved. My 1972 designed wooden scow International Moth is almost half this weight again, and modern day Int Moths are half the weight of mine so it's interesting to see the possibilities when minimum weight is not an encumbrance.
ReplyDeleteI'm looking forward to having a browse around your very nice blog and thanks for stopping by to have a look at Max Headroom's progress.
Glad to hear that you're enjoying my blog. Mark was shooting for a hull weight of 75 lb. Although the boat hasn't been weighed on the official CMBA scales Mark's best estimate of her current weight is in the low to mid 80 pound range. I've posted the URL for your blog on the CMBA's yahoo email user group so no doubt you'll see an up tick in visitors over the next few days.
DeleteWithin the Classic Moth Boat Association (CMBA) we have argued back and forth about the minimum hull weight which the club adopted in its founding back in 1991. The original Moth rules don't have a minimum weight restriction. Some of our members remind us that expensive composites such as carbon fiber, kelvar and the like were not available in those days and that one way to insure that someone with deep pockets doesn't dominate the race scene is to have a minimum hull weight that is easily achievable with relatively inexpensive ply panels. Working with 3mm marine grade ply one can easily build a robust and competitive hull that comes in at minimum weight. Other members keep hammering away at our somewhat antiquated sail plan. Indeed we have voted to update that for the Classic divisions while retaining the original spec for our oldest, Vintage division boats. Basically we don't want to go the way of the foilers. We've come to the conclusion that a bunch of cranky old men don't need to spend the better part of $20 grand to have a bit of fun! A competitive Classic can be home built for a tenth of that, including a new sail.
DeleteI agree George! It's never a good idea to make huge changes to the rules that will make the whole fleet redundant. Look at the success of the Laser. It's 60's tech, heavy and slow, but it's still the biggest class in the world and very technical to sail it well.
ReplyDeleteAs for materials, they don't make boats strong by themselves. Good architects know that 90% of the strength comes from the structure, so to build lighter you use lighter materials but of course change the structure to suit. For example, the frames in my Moth are very strong even though made from 1mm 3-ply. You just have to use the appropriate structures. Using 6mm 5-ply for it's frames using the same structure would just make the boat heavier, but no stronger!
Incorrect use of carbon can make a heavy boat too. For example, if you just substitute carbon of the same thickness and dimensions as ply, you end up with a heavier structure, simply because carbon/epoxy is more dense than wood or ply used in boat building. For example, the rudder stock on Mark's Classic Moth. As a flat slab of carbon it is probably 3 times thicker than it needs to be to do its job, so it is three times the weight it needs to be. One possibility is to judiciously remove about 70% of it and it will still be strong enough to do its job. The same thing goes for timber, and I will use Mark's tiller as another example of the possibilities. You can design in the strength by making a composite timber/epoxy structure while using 1/3 of the timber contained in his boat's tiller. It will be just as strong, but of course 1/3 of the weight.
However, there is no real sense in building a 20kg Classic Moth and then having to add 55kg of lead so you may as well use “heavy” building methods. Certainly, a 20kg timber Classic Moth would be possible to do in timber, so there is no argument at all to support the use of carbon in this class. However, to build it under 10kg would definitely require the use of carbon composites. The boat's rigging is an entirely different matter and carbon tubes to reduce weight aloft should be used wherever possible.