A Real Hull Model

The Calendar Iands Yawl

Hull Modeling in the flesh: part 1

CNC cutting parts for a quarter scale model

The 3D computer model is sliced up into sections that become molds for defining the hull shape.

You can see the molds formed now, trimmed to the hull surface,  and one more to go!

The hull is planked and ready to be broken up into the "flat" 2D geometry.

A neat screenshot that shows the 3D and 2D nature of the work: in the foreground is the 3D hull model. In the background is the geometry flattened onto the "construction plane".

This is the file with the 2D geometry as received by the CNC cutter, CNC Routing & Design in Camden, Maine. Tim will load the file into his Shopbot software, make toolpaths, and cut the parts.

The ShopBot machine cuts to my lines with a couple thousands of an inch accuracy. These are the planks of the boat, the bottom keel plank in the center and the sheer strake to the far right and left.

The molds of my quarter scale kit around which the planks will be wrapped and checked for fairness and for fit.

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A Deblois Street Dory

to The Compass Project in Portland, Me is building a DSD with a group of kids and they are doing a great job.

The boat is built like dories have always been built, using the bottom to erect stem, frames, and transom, then turning over the boat upside down on a strongback. Everything is plumbed and braced then planking begins.

Here the garboard has been installed and the sheer clamp is being fit. This is the only departure from traditional dory construction, the incorporating of the clamp helps tie together the frames into plumb and lock in the ends of the boat. It is a bit of a 3D puzzle!

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Last week I finally got up to the Belfast area to see Jewell. This one is the first US built hull, so it is exciting for me having spent the last couple years collaborating with the designer, Francois Vivier, to work out a boat that would be popular for our market here in the USA and Canada, be fun to sail for weekend warriors as well as families, and not be terribly complicated or expensive to build.

Jewell hull #2 under construction in Belfast, Maine.

I mentioned in the last post that sometimes when you go from virtual to physical reality with a boat design, somethings don't look or feel quite the same. But with Jewell, she is exactly as we wanted her to look and feel. The lines are great, her proportions are great, and the boat will be roomy for a 20-footer, or 19'8" to be exact. In the photo above you can see the transom. Here is one of two pieces of custom SS parts to be fabricated, the rudder housing...

Rudder head for Jewell

The bulkheads and planking in the kit went together without any fuss and all the inside components have already been check for fit. Things drop right into place on the inside. We're working out some details regarding limber holes and placement of hatches and the plans will reflect those changes. Pretty soon the rig will be going up and Jewell will sail.

Regarding sails and hardware, an extensive list has already been made based on the dozens of boats Mr. Vivier has rigged. His specialty is gaff rigged boats and, while the yawl is new for his catalog, it is one of my specialties. Sails are made by our favorite Maine sailmaker and the custom hardware like the rudderhead can also be made here in maine and shipped out to a kit builder anywhere in the US or Canada.

Email me if you are interested at boatkits@gmail.com

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Deer Isle Koster "KDI" Kit Version

Hull #3 of the KDI will soon be cut on the CNC machine and built. The computer model is a refined version of the first two built out west for designer Bruce Elfstrom. The modeling was done in collaboration with 3D CAD extraordinaire, Dan Clarke.

We will keep folks posted as the first kit version is cut, built, and released to the market sometime this Fall.

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A trip to sail the Deer Isle Koster aka, "KDI"

The Deer Isle Koster is a new kit that will hit the market by November. We are very excited about

this addition to the catalog. I finally had a chance to sail with the designer, Bruce Elfstrom, at his summer camp on Deer Isle in Maine. Bruce designed these boats for his daughters to sail. It is always wonderful to visit the provenance of a great design and to sail with the designer!

I was most struck by how high the KDI pointed sailing upwind. The foils and jib headed lug rig are very effective. I was also struck by how nicely the helm balanced and, overall, how easily she sailed. I was most satisfied about this last point because this little boat will make a great boat for introducing children to sailing small boats.

Both well over 6' and 200 pounds (I will not go into specifics!), Bruce and I had plenty of room in the cockpit with room for kids and under deck places to stow snacks and other gear.

We are currently finishing the 3D model work which will be used to make the 2D parts that are cut on a CNC routing machine and become the basis for the complete kits. To learn a ton more about how this works please read a PDF about boat kitting.

Also feel free to visit the WoodenBoat Forum thread on the KDI.

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New Stitch and Glue Dinghy

Congrats to Barbara Simon, the new owner of the Willard Beach Dory (WBD), a new stitch-and-glue dory skiff drawn by Roger Long who has retired and is off cruising. Roger left behind a few gorgeous designs for me to 'kit' and market as new boats, the (WBD) being one of them. The others are the YawlDory and a 16' Herreshoff-like double paddle canoe, which is a thing of beauty and may be the only paddle boat I end up putting in the catalog.

The WBD is out of 6mm plywood and will be rowed in and around Casco Bay. She'd be an ideal tender being light, maneuverable and a good load carrier. The oars are our custom spoon blade oars with high quality 14" leathers by Swanson Boat Company.

Stitch and Glue is a quick way to get a boat, but this project was a reminder that this type of construction can take longer than one thinks if you try to get a yachty finish: hiding the fiberglass tape and fillets takes some fairing. With lapstrake, there is a clean plank line to follow. However, the S and G structure is light and strong and relatively inexpensive as kits go.

What other S and G designs do people like that are not available as kits and should be?

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Small Reach Regatta Finishes in Drake Rowboat

This sail is right off a Shellback dinghy, but a new more efficient downwind rig is in the works when we aren't making other peoples' rigs!

(photos by Christophe Matson in his Goat Island Skiff)

My wife, Ellie Chase, and I finished up a fabulous 3 days of rowing and sailing in Drake along with almost 40 other boats ranging from 12 foot dinghies to 15 sail and oar boats, to 22 foot daysailers. Drake often got to the lunch stops first because we were able to row upwind and sail downwind. It turned out that most of the time we rowed in tandem.

We love this mode of boating for getting around but you have to like to row and be in a good rowboat. And there is no need to ruin the lines of a rowboat by making it be able to sail, as long as you stick to sailing off the wind. We can sail easily on a beam reach down to a run. In the above we maintained 3.5-4kts in maybe 5-10kts total true wind.

See more at http://www.facebook.com/groups/104933556820/

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Back to business: boat kits and complete boats

First off, I am now in 100% complete control of my Gmail account again. Someone in Egypt hacked in because I was not careful enough about protecting my password. Upgrade passwords and never have it on email anywhere! Learn from my mistakes. My email, boatkits@gmail.com, is completely safe, now.

Pictured is a recent boat kit heading out of the shop...CNC (computer numerically control) precut plywood kit and a timber kit. The pieces of mailing tubes over the ends of the long parts protect the precut scarf joints while the kit is shipped (this one a kit to Durango, CO).

Back to business and to pick up from the last few posts, I want to share a PDF and link to my webpage about how my kits are produced, why it makes more sense to built boats out of my catalog from kits or full size patterns, and the general idea regarding the 'economics of boat kits' (i.e., why the extra cost of a boat kit is smaller than many think) will come next time.

http://www.clintchaseboatbuilder.com/CNC.html

My pitch for building from boat kits PDF (Google Docs)

In a nutshell, boats designed in the computer are actually drawn full size already to a higher degree of precision (thousandths of an inch) than on the lofting full size by hand (1/16th's of an inch). The difference is that a planks can be precut in advance, glued together with a precut scarf, and bent around bulkheads, hitting every mark on the spot. Interior components and the building jig itself are drawn into the computer model to exactly fit the boat. Therefore, to take a computer aided drafted (CAD) boat and loft it by hand introduces natural errors that were carefully avoided in the CAD process.

Because the parts can all be predetermined off the computer model, they can be nested onto fewer sheets of plywood than a manually (scratch-built) boat can be done. Also, it avoids cutting mistakes which often requires buying extra wood. This offsets the extra cost of a kit and wastes less wood.

The time it takes to manually cut parts to a boat, if you look at it in a hourly rate kind of way, would also offset any remaining difference in cost between building from scratch versus building from precut parts in a kit.

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Economics of Kit Building

I receive a lot of questions and comments regarding the true cost of building a boat from scratch, full size patterns, and kits. Since I track time and materials closely, I have found that building from kits makes a lot of sense from an economic stand point. I took some discussions with customers/potential customers and put together this PDF on the 'economics of kits'.

In a nutshell, the cost of building from a kit is not as much more than building a boat from scratch as people think because of the extra plywood required to build from scratch not to mention the time savings.

In the meantime, we are making progress on the first professionally built Goat Island Skiff (yawl version) which will be at the Maine Boatbuilder's Show in Portland on March 18-20th. Please stop by. We'll be in building 2 near the stairs up to food court.

When I post next, I'll have a PDF link that goes into more detail about how the designs/kits are produced in CAD and CNC cutting.

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Quality Plywood & Epoxy Encapsulation

I am a believer in epoxy encapsulation of wood; I wasn't always. Encapsulation entails coating the wood with multiple coats of epoxy, saturating the wood surface and building up a moisture-barrier. The moisture barrier is key for bilges and underbodies as it keeps water out of a laminate and maintains a more constant wood moisture content in timbers. Wood movement and ingress of water is what often gives wooden boats a bad name: high maintenance. Encapsulating forms a stable base for varnish and paint. We tell customers to expect a 10 year life for their paint. After 10 years of normal use they may need to do a fresh coat. That is as good as any fiberglass boat maintenance.

What convinced us of the merits of epoxy encapsulation was a visit to my friend Steven's house. He has a faering he built with his son that shows the effects of different plywoods and of epoxy coating wood.

You can see three panels in this Faering. The darker plank is Joubert Sapele faced Okoume (varnished), the middle strake is Okoume by Joubert, and the lower plank in the photo is Shelman Okoume. All planks are finished with a Behr spar varnish.

This is the same boat closer up to one of the tanktops. It is Joubert Okoume. The neighboring plank is Shelman Okoume. Both were varnished the same. The tank top is more degraded and molded than the plank. The tank top along the edge of the plank is perfectly clear. This strip was inadvertently epoxy coated when the squeeze out from the glue joint was spread during the clean up process. The same thing happened in the next photo: can you see where the epoxy is?

The results? It is clear that the epoxy coated areas of plywood are making the plywood much more durable and holding up much, much better. The sheer strake is probably holding up better because it is higher in the boat and receives less foot traffic and a lower angle of sunlight upon it. The middle strake and tank tops get more direct sunlight. But the different brands of plywood may have to do with the difference between planks made of Joubert vs Shelman. It is too bad Shelman went out of business. Clearly, Sapele holds up great and Steven made a good decision putting it in as the garboard. With that said, I have also seen Sapele planked boats flake and shed paint after many years and these were boats that were not epoxy coats.

The moral of the story: epoxy encapsulation is a good thing.

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Wooden Boat Show Family Boat building

We are catching up with a nons stop summer of boating events and where best to start the series of updates than with the Wooden Boat Show in Mystic, CT. In 2 1/2 days, a father son duo built one of our Echo Bay Dory Skiff kits. They discovered that there is a lot of boatbuilding, sweat, creativity and work to do even starting from a kit.

 

They launched on the third day at 3pm. They were very proud and perhaps glad they had a break to enjoy their success. My former life was a teacher and instructing people to build their own boats. Getting new folks into small boats, building their own boats from kits, and experiencing success in everyway is the number one priority for our customers. Likewise, we felt this year's Family Boatbuilding was a success and will plan to do these boats again next year.

 

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Yawl should know the conundrum of getting a tiller 'round the mizzen mast

The details of how to design a yawl so that the tiller gets around the mizzen is an interesting topic. There are a number of tricks:

Using a line steering system: Here you can see Michael Storer's Beth Sailing Canoe with the tiller forward of the mizzen and the lines connecting to the rudder, which is out of the picture.


I'll add that there are a number of ways to do line steering. My Deblois Street Dory has line steering coming into the boat from a rudder yoke but there is not a remote tiller as in Beth. The Coquina is another example of line steering in which lines are attached directly to the rudder and pass through the transom, via a pulley system, and the steering line goes around the perimeter of the boat.

Using a long push-pull tiller: Here you can see James McMullen's Oughtred's double ender.


Using a curved, laminated tiller or split tiller


Using a normal tiller with an offset mizzen




For the Goat Island Skiff, we go with an offset tiller as in this model by a customer:




The other methods I mentioned just won't fit the situation we have in the Goat Island Skiff, mainly because there is not room for a split tiller and we want to keep the solution simple. We are deciding about just how much to offset the tiller. You can see above that the tiller will hit the mizzen before 45-degrees. The big question is how much room do we want to give the tiller to swing. In the pictures, we decided to test a 45-degree swing. That puts the mizzen a little further off the centerline than I'd like. This boat is very light and pushing a tiller than hard over makes the rudder act like a brake and the risk of losing so much speed that you can't get through the tack is something to consider. Then again, we don't need it so close that things feel claustrophobic. In the picture above of the offset mizzen, notice how little offset the mast is...the tiller must touch the mizzen pretty early. Does that give enough steerage for the helmsman when the push the tiller in the mizzen direction?

We'll have a solution soon after a full-scale mock up. The way we are doing this, collaboratively, is something I do on many projects. It always gets a better result because many thoughts and ideas can be sifted through. The more the merrier. Whatever the solution I draw up, the mizzen can always be moved a little more or less off the centerline according to the skippers preference. The important thing is to maintain the rake of the mizzen, which has been determined. My point is, that collaboration with designers, customers, and other folks with experience through the forums and boat shows can be an advantage in getting many thoughts onto the table and generating the best solution.

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Why the Yawl Rig for the Goat Island Skiff or for any boat?

I am asked this a lot and wanted to put something together to answer this and other questions. I added the mizzen to the GIS because I wanted a boat for myself that would be easier to singlehand on longer excursions and for use in sail-and-oar events such as the Small Reach Regatta, the Texas 200, and other RAID events like the Shipyard School Raid and Sail Caledonia. Many, many of the boats you see in these events have a mizzen.

For my own use of the GIS, a mizzen is needed for a variety of reasons:

1) to hold the boat into the wind while the sail is raised, lowered, or reefed while singlehanding or sailing with my kids.
2) to hold the boat into the wind while rig is unstepped and stowed and oars are rigged for rowing
3) to be able to hold the boat to windward or to heave-to while underway for taking short breaks to move people, re-stow gear, or go to the bathroom with out getting blown off course.
4) to be able to back off docks and beaches and control steering in tight spaces
5) to be able to 'tune' the weather helm felt by the helmsman by trimming the mizzen

Other FAQ's

Is the designer aware of your changes to the Goat Island Skiff?
Yes, I have a great working relationship with Michael Storer whom I consider a friend. He and I correspond often and he has OK-ed the addition of the mizzen and trusts that I will design and build the new rig so that it fits in with the concept of the GIS. For example, all pains will be taken so that this addition adds very little weight to the boat. The mizzen mast will be a lightweight, birdsmouth mast.

Is the lug sail the same and is it stepped in the same place or how has the lug's position been adjusted for the new mizzen?
I have designed new sail rigs for boats before, for dories actually. After drawing the new rig, finding the new center of effort (CE) of the added sail area, and moving things around, the new CE and old CE are in the same place such that the centerboard does not need to be changed. In the GIS, the lug is the same standard sail (105 SF) and it will step in a secondary partner/step forward of bulkhead #1. It turned out that the lug needs to be moved forward only 9" keeping things tied into the bulkheads for structural integrity and simplicity. The original mast step is retained so the boat can be sailed with or without the mizzen. The GIS Yawl is is still the usual standard GIS, but with an added mizzen. You can take the boat out with more flexibility in rig choice.

Has one been built and how well does it work?
I expect to have a GIS Yawl on the water this summer, my personal boat, but orders for sail rigs and boat kits may prevent that from happening. However, one kit is going to a customer who will be doing the yawl and plans to be sailing this summer in the Texas 200. I have no doubt that the boat will go as well as the standard, upwind and downwind, but with the added benefits of the mizzen for RAIDs and sail0and-oar type of use. If the mizzen is not needed, leave it ashore and use the Goat as the standard lug-only arrangement.

You can learn more about How to Use the Yawl Rig in my blog post.

or the Goat Island Skiff page on my website.

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Boat Kits and Information About Kits

'Tis the season for kitting out boats here in the shop. It is keeping the business very busy as we finalize the Goat Island Skiff kits and in January we'll be "kitting" Clint's design, the Drake Rowboat.

FAQ's

What is unique about our kits?
Clint's kits are the equivalent of a professionally built boat, dry fit to perfection, and then taken apart and packaged so that you can replicate the results at home. That means the hull lines will be "eye-sweet" and beautiful when you assemble the boat. The numerous and subtle tweaks that a professional builder does to make the lines of a boat 'sing' has been done for you. This is the unique part of our kits: the kit is not cut directly from a computer file, but rather comes from directly from a hull built by an accomplished boat builder.

What is included in a boat kit?
Our kits have a number of options to suit your timeline and budget. One option will always include plans and the plywood components, planks and bulkheads or molds. The plywood is BS1088 Okoume and comes from Maine Coast Lumber, a trusted source for us. Timber kits are available. Pre-laminated components are available, frames, stems, and backbone components. A further option is a complete timber kit that gets you set up with seats, gunwales, floorboards and all the wood you need to build the boat. You can see kit information at our website kit information page.

Why buy a kit?
When I suggest to people that they buy a kit they sometimes are offended because they feel we don't think they have the skills to make their own kit. The truth of the matter is that we build our own boats from kits as well. In fact, a successful Pro Boatbuilder will build from boat kits himself. The reasons are the same as for you and me: it saves a lot of time, it saves money due to less waste in materials and less wasted time, and the results are a better boat. The boat fits together with less fuss and the lines are reproducibly beautiful every time.

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Goat Island Skiff Boat Kits Available

Our first kit offering at Clint Chase Boatbuilder is a plywood and timber kit for the Michael Storer designed Goat Island Skiff (GIS). Why buy a kit? Folks are sometimes offended when I suggest this, feeling that it is thought they don't have the skills to make the parts themselves, but that is not it at all. We build all of our boats in the shop from kits!!! Even professionals do it and the reason is that it makes the build process quicker and smoother and the result is more professional. In the case of the GIS, we have made parts and built the hull of the boat, making all the small tweaks that professionals with a good eye make to the lines of the boat to make them look eye-sweet. Any design, no matter how well drawn, will need some eyes on it in 3D to make final tweaks. We also have checked bevels and made some adjustments for a rabbeted gunwale, which covers the end grain exposed at the top of the gunwale. Our kit captures all these professional practices so you can get a better boat. Currently, kits are cut per order, but we may move to CNC when volume increases.

We were attracted to this design initially because of the sail plan, a beautifully proportioned Balanced Lug. Upon further reflection we noticed something was missing for RAID sailors and for others who might use the boat as a sail & oar craft. It needed a mizzen. A small mizzen gives great control of a small boat, allowing one to lie head-to-wind for reefing at sea or for heaving-to. It allows you to back off a beach or a dock, with practice. It is useful for trimming the sail plan, adjusting weather helm to create "feel" in the tiller. A mizzen makes single handing much easier, especially for switching between oars and sail, because the boat will tend itself and stay head-to-wind while you stow oars and fidget with things at the mast. For a useful diagram showing How to Sail a Lug-Yawl, by James McMullen.

We can supply a kit for the GIS as well as the mast and spars. Masts are round, hollow using the Birdsmouth technique. Yard and boom for the GIS are solid, laminated Northern White Spruce. Laminated spars stay straighter over time with changes in moisture content in the wood. We can make custom 9' oars specifically designed for the GIS. Rowing in the Goat Island Skiff is quite enjoyable, whether it is from the dock to a local area with wind, or coming back when the wind has petered out. Products for the Goat Island Skiff can be seen in the GIS Flyer on our website Goat Island Skiff Page.

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