No Greater Passion for the Craft

Math Matters: The Geometry of Restoration

2012-02-16T13:53:00.001-05:00

Image courtesy of Andrew Williams

If you have been following these blogs or checking in on our website or Facebook posts you’ve noticed that these last few years have been filled with a lot of restoration here at Rockport Marine. It occurred to me that there’s a part of that restoration process that is almost completely hidden from view.

Photo by Billy Black

Comprehensive restoration is about returning to a yacht to a prior condition. Yes we often make “improvements” with respect to systems, but a strict constructionist’s reading of the restoration Constitution would demand that we replace the word “improvements” with “compromises,” and for my part I’m inclined to concede the point. You’ll occasionally come across the phrase “better than new restoration..." which is a concept that must have been invented by a broker looking to sell a boat, or an owner trying to explain to his accountant where those particular dollars went exactly. The line gets blurred even further by those of us who have adhered strictly to an original design but executed the work to a level of finish and polish that the original vessel never carried and the original designer probably never intended. I think this is what RMI’s head boatbuilder, John England, is referring to when he talks about “professional arrogance." Still, returning to a prior condition was the goal; we all get a little carried away at times.

What "getting carried away" looks like. Photos by Alison Langley

When it comes to the geometry of a restoration, we’re interested in one prior condition in particular, that is, “original condition.” But even that can be tricky. Do we have the designer’s original lines plan, or better yet, a table of offsets? Even if we do, given the nature of printed and photocopied media, are there concerns about distortion? Was the boat even built to the original lines plan? Has it been altered or modified in some way since? Have the ravages of time and decay altered the shape? How can we tell? There are a lot of questions, and if you’re to have any hope of answering them you have to measure the boat.

It turns out there are several ways to do it. The best way depends on the available time and budget, where the vessel is located, and the degree of accuracy required. Broadly speaking there are three reliable ways to measure a boat; you can do it manually, you can do it with a camera, or you can do it with light. For a variety of reasons we don’t use the first two methods. For that reason and because the manual and photogrammetric methods have already been described well in WoodenBoat Magazine, I’m just going to focus on the last one.

3-D imaging is the process of using light to take accurate measurements. Specifically, it refers to the process of directing laser beams in a controlled manner at an object, then obtaining extremely accurate distance measurements from you to that object from a multitude of angles. This is lots of measurements. Lots, like millions. It can be used to measure a computer chip or an ocean floor. We use it to measure boats, or rather we use Andrew Williams, and he uses it to measure boats for us.

The product or output of this measurement process is a series of points, each with an xyz-coordinate. Remember Cartesian coordinates from high school and college?

Well the box is really big, and the grid is really small, and the file size is huge. Like 60 gigabytes huge. That’s partly because it registers millions of points on the hull, and partly because the equipment doesn’t know you just want the boat so it measures everything. I mean everything. It’s called a point cloud. When Andrew first measured Bolero inside our shop, the whole building was in the point cloud. The bandsaw was there, the table saw was there, the gantry crane was there, you could even see where people had been standing. It reminded me of scenes from The Matrix.

Point cloud image in the rough. Courtesy of Andrew Williams

After measuring Andrew begins what he calls “thinning”, essentially throwing out the millions of points you’re not interested in, and the file size comes down. Next he creates something called a mesh from the points, and again the file size comes down. A mesh is a series of polygons connecting every point in the point cloud. The resulting surface, or collection of polygons, can look crude or quite refined depending on the number of points. Take a look at these polygon meshes of a hand and you’ll see what I mean.

Andrew has to measure a bigger surface to be sure, but also has far less rapid shape change and millions of points to work with. At this stage in the process he is able to do some smoothing or fairing as needed, always with the ability to limit allowable deviation from the measured points. The final step is to convert the mesh to Non-uniform rational B-Spline or NURBS geometry. It’s here that the filesize drops to a useful size of a few megabytes. I have to confess I can’t explain this last process of converting a polygon mesh to a NURBS surface. It requires a level of mathematical understanding that I do not have, but sufficient to say this last part is done with specialized software. NURBS geometry is what’s used by design professionals to design everything from cell phones and cameras, to jewelry and yachts. If you’ve ever seen a computer model rendering of anything that doesn’t yet exist, odds are it’s due to the work of Pierre Bezier and Paul de Casteljau, creators of NURBS modeling program.

In the end what we have is a computer model of the boat. It’s a simple matter to reproduce the designer’s grid of waterlines, sections, and diagonals and project them onto the hull model. Print this at a corresponding scale on transparent media, and you can overlay the existing lines on the original lines to analyze how the hull shape differs from the original boat, or at least from the boat the designer originally intended. Furthermore, if we thought to record where the boat was floating before we took it out of the water we can use the model to rapidly and accurately calculate, moment to trim, sinkage, displacement/weight, wetted surface area, and various performance ratios. Armed with that data we’re much better placed to enter the conversation about whether those proposed changes are improvements or compromises after all.

-Brendan Riordan

Island Escort: Old Made New

2012-02-08T11:07:00.002-05:00

Not so very long ago we had an opportunity to prepare a presentation design for an individual interested in getting to his property on a nearby island and back again. The design requirements were speed and grace. A passing reference was made of the fact that it should probably look like it belongs in Maine. Also, it’s likely that it will be used for the occasional tour of the island. A beautiful boat, sunset, Maine Islands and a gin and tonic. Just add lime, the rest was up to us.

The design brief immediately called to mind a collaboration between Rod Stephens (brother and co-worker of the famous designer, Olin Stephens) and designer Al Mason. In 1940, Commodore William Justice Strawbridge commissioned a design for the expressed purpose of cruising the islands around Penobscot Bay. Stephens and Mason called the result ESCORT. When a client came into the design office and asked for speed, grace and a distinctive design that would still look at home in a rocky harbor in Maine, ESCORT struck me as a pretty good place to start.

This is a great boat, period. But no self-respecting designer is going to show a client someone else’s boat. So whether or not I believed it at the time, I felt that we could do better.

Enter the design work of a man named A. M. Deering, introduced to me through the writings of Maynard Bray. If you fancy yourself a designer you’d do well to immerse yourself in Maynard’s writing. He and Anne Bray, his wife, wrote a book titled Designs to Inspire: Selections From the Rudder, 1897-1942. The Brays describe Deering’s striking beautiful 1935 effort, HILLHARRE:

“Moderately streamlined with an automobile inspired pilothouse, HILLHARRE still looks attractive even after 65 years. Deering’s handling of the transition between trunk cabin and pilothouse, which incorporates a continuous belt line under the windows and a faired-in lower windshield edge, are both distinctive and handsome. Judging from the plan view, her hull and great flare forward and extreme tumblehome aft, making her a worthy progenitor of the shapely Florida sportfisherman. HILLHARRE’s builder was J. Walter Jones of Wittman, Maryland.”(“Sportfishing Cruiser HILLHARRE,” Designs to Inspire, p. 156)

Another great boat. Sure, there are elements that I don’t love. On the whole I think it is evocative of an era that we weren’t keen to retain in our design, and I suspect the dramatic curvature of the house top and the lack of rake to the front of the house are partially to blame for this. Still, there’s enough inspiration in those two boats to advance a dozen new designs. Our effort was born of the Stephens-Mason collaboration and carries the name they selected. The sheer, dramatic tumblehome, nearly plumb stem and transom, pilothouse window arrangement, even the aft overhang and downward slope to the pilothouse top all pay homage to Deering’s HILLHARRE.

-Brendan Riordan

The Model Room

2012-02-03T10:33:00.004-05:00

For anyone who has even the slightest affinity for boats, a visit to the New York Yacht Club on 44^th Street in Manhattan is a treat. The building was built in 1899 and designed by Warren & Wetmore in the Beaux Arts style; its limestone façade is fitted out in a whimsical, nautical style with windows that protrude like the transoms of galleons. The main dining room is fitted with large hanging knees, and the effect is so shippy, you half expect your peas to roll gently off your plate.

But the jewel of the club is the Model Room, space that displays a huge collection of full and half hull models of some of the most famous designs in the world. Brendan and I had the opportunity to visit this room for an International Yacht Restoration School reception at the club. On entering the party we could not help but be drawn to the wall of models, and to press our noses against the large glass display cases of fully rigged miniatures chronicling the history of the America’s Cup competitors.

Jerry Kirby gave the keynote address at the event. This threw us for a bit, because we confused him with George Kirby, of Kirby Paints, who makes traditional linseed and lead-based paint. It seemed like a strange forum for a talk about paint.

Turns out that Jerry Kirby is an “extreme sailor” and our ears perked up hopefully when he dropped a couple swear words into his opening remarks. He did not disappoint, and spoke vividly of various adventures, including the Volvo Ocean Race, and the capsizing of RAMBLER during the Fastnet Race while she was on-pace to shatter the speed record. I was fascinated with his stories, as I am with any sort of sailing that involves a helmet. The idea of “averaging” 30 knots in an ocean race is both exotic and terrifying. It seems a world away from sailing classic yachts, that was so much in evidence around us, and made an interesting counterpoint to our evening in that beautiful space.

-Maria Simpson

Cockpit Conundrums

2012-01-30T14:13:00.008-05:00

I’ve noticed that when my work comes up in social situations the conversations tend to be brief. But I have it on good authority that there is some indication one or two of you are actually reading these posts—which is, of course, encouraging. I would describe my reaction as just shy of surprise when I heard that. Perhaps what I had attributed to a less than compelling topic of conversation has more to do with my shortcomings as a conversation partner… but you’re reading, at least a few of you, so for the time being I’ll keep writing.

Yacht restoration is a curious endeavor. My impression is that archivists, fine art conservation specialists, and other restoration professionals have had the benefit of formal education specifically tailored to the restoration process. With the exception of graduates of the International Yacht Restoration School in Newport, Rhode Island, (which, by the way, has a fantastic reputation) the rest of us in the field of yacht restoration are on our own. We’re here because we like pulling things apart and putting them back together, because we’re methodical, and because it’s fascinating.

I used to worry about my lack of schooling specific to restoration. Sam and I both trained in yacht design. We’ve each even received a few paychecks working as boatbuilders in this yard and others, though that was both brief and long ago. But I can’t really claim to have been schooled in restoration per se. I look up these days and notice that we’ve spent a fair bit of time helping the Rockport Marine crew restore some pretty spectacular yachts.

Besides, one danger of having framed diplomas and certificates that establish you as an expert in your field is that you might one day begin to believe that they do. The best part of not having them is that you get to ask questions of everybody. I’ve got access to machinists, fabricators, wood-workers, mechanics, electricians, systems engineers, painters, purchasing officers, riggers, sailors, accountants and business managers all under one roof. Expertise doesn’t begin to cover it. It’s pretty awesome to be a part of what happens when you have that crowd to learn from.

Here in the Rockport Marine design office there’s a sort of ongoing debate about the best way, the right way, to approach Restoration. You’ll hear things like “How much do we replace? Should we use a different material here? How much deference to the designer and original builder is appropriate here? Even if the original design broke? Okay so at some point in the last ninety three years a structural component subjected to a marine environment and an unknown number of load cycles failed. You’re telling me that scenario doesn’t exceed the design brief for this part? So what’s your criterion for success?”

If you’ve been reading these posts you know we’re deep into the restoration of the 83’ Fife Schooner ADVENTURESS. I don’t think any other part of the job brought more of these questions swirling to the surface than the redesign of the cockpit. Aesthetics, function, whether to re-use the original steering gear, the relative wisdom of “improving” on design of portions of the original equipment, all were considered, debated, settled, re-opened, argued, settled. “That’s it. Agreed? No, sincerely, I don’t ever want to talk about that again. Crap, you know what we forgot? How do we attach an autopilot to that thing?”

So here it is. Before and after. Well not so much “after” as “during,” plus a rendering of what I think it’ll look like once the incomparable Tom Dayhoof is finished with it. I’ll post more photos later for “after”. The concept of “final” is comedy in this field.

-Brendan Riordan

Worth Doing Right

2012-01-22T14:07:00.004-05:00

WoodenBoat Magazine used to run a feature section called Matters of Detail. I always lingered on that page. The descriptions were brief and usually accompanied by a photo of some especially clever solution to a common boatbuilding challenge exquisitely rendered in oak or bronze. Something tells me Maynard Bray was behind it but I could well be attributing one of his colleagues’ good ideas to him. Anyway I haven’t seen the Matters of Detail section in a while. Truth be told it never quite seemed to fit in the magazine. I remember it as a welcome non sequitor in the middle of the issue. In a way it was the first boat blog; little testimonials to people living out the axiom if it’s worth doing, it’s worth doing right.

But here I am writing a boat blog from the design office at Rockport Marine. The shop bays here are a revolving museum of some of the finest wooden boats ever conceived. There are some 50 odd men and women creating these matters of detail here every day. You could argue that here in the design office it’s a big part our job to scheme these things up.

Trade publications have been generous in featuring our work in the pages of books and magazines, but the sheer quantity makes it impossible to feature this level of detail in an article. So I’m going to poach the idea and use some of these design office blogs to feature the details that go into these projects.

It’s not every day that you get a chance to design a fireplace for a boat. The main Salon for Adventuress presented that opportunity and the result is quite stunning. Designers talk about the design spiral. It’s the process of identifying a problem or challenge and devising a solution. It happens iteratively, adding detail and identifying additional complexities each trip around the spiral until you’ve answered all of the questions. One of the best parts of working at Rockport Marine is that this process is collaborative here. Project managers pose a challenge. Designers sketch, refine, sketch. Project managers brainstorm improvements with the person who will build the piece. Designers incorporate feedback, draft, 3d model when needed. Patterns are plotted. Builders refine. And in this case when we’re too busy to do it all ourselves, Josiah Bartlett and the crew at Rockport Steel took the lead on fabricating the steel fire chamber. And there it is. How cool is that?

A Charlie Noble is a pretty simple thing really. Really it’s just a smoke stack on a boat. Sometime in the mid 1800’s a British merchant service captain, Charles Noble, discovered that the stack of his ship's galley was made of copper and ordered that it be kept polished. From that day to this, ship's crews have referred to the galley smokestack as the "Charlie Noble." We use them all the time here at Rockport Marine, but to the best of my knowledge we’ve never before put one in the spine of a butterfly hatch skylight. Hank Keane and Rob Ball at Edson International are the best in the business for custom castings like this one. They are in the process of casting this for us so we don’t have the finished part yet, but here’s a rendering of the part.

Designing and fabricating all of the rigging hardware for an 83’ Schooner is an enormous task. Take a look at some of the collaborations between Ian Bruce and the Rockport Marine fabricators Joel, Carl, and Chris. The design and fabrication of custom hardware for ADVENTURESS deserves a blog all its own. Stay tuned for more…

-Brendan Riordan

Home for the Winter

2012-01-10T13:25:00.008-05:00

Rockport Marine is the winter home to many offshore cruising and racing boats that have participated in the Bermuda Race or have crossed the Atlantic. Tom Kiley, service manager and rigging expert at Rockport Marine, has been a Bermuda Race inspector for 20 years. He can be found on the dock in the warmer months preparing our storage boats for the sailing season, offering advice and troubleshooting any rigging issues. All our customers know him for his practical advice and he is an invaluable asset to anyone preparing for a race.

“When you enter the Bermuda race, you get a long checklist of standards for safety gear, hull structure and volumes,” says Kiley. “As an inspector, it’s my job to make sure a boat is compliant with every single item on that checklist.”

Tom consults on sails, rigging, communications, navigation, structural integrity, safety gear, systems and crew training. He has been involved in many Rockport Marine restorations, helping owners who are interested in qualify for the stringent requirements of modern offshore racing and voyaging, but also want to maintain the elegant, period details of their boat.

Bolero , the 73-foot Sparkman and Stephens-designed ocean racer, former flagship of the New York Yacht Club fleet, was recently restored at Rockport Marine. It was important to her owners that she retain many of her original, 1949-era details, but also be able to qualify for modern races. For example, it was necessary to change the location of her running lights, so they would not be below the rail. She also was equipped with two bilge pumps, one that could be operated from down below, and one that could be operated from the cockpit, that were plumbed entirely separately from one another.

“Although many of our boats are older, “classic” designs, we can outfit them with state of the art systems to make them safe and capable for offshore sailing,” says Kiley.

-Maria Simpson

Under the Skin

2012-01-09T08:20:00.002-05:00

There is no doubt that everybody loves the traditional plank on frame sailboats of a bygone era. The challenge is to keep the authentic looks of that era while making them modern in performance, safety, and manageable for a small crew. Many of these 1920s era boats were day sailors, with a crew staying aboard to polish the hardware and assist the captain while day racing in the Solent or the river Clyde in Scotland.

Nowadays the modern classic yacht is an ocean going vessel, has all the systems of the new designs but must be hidden between the skins, under the sole or other out of sight places. The trick is to do it right once, have it totally reliable and invsable but accessible.

Hidden between the skins on the starboard side of the 83’ Fife-designed schooner ADVENTURESS, there are no flexible hoses and hose clamps; all non-corrosive metal pipes handle the fluids with seacocks at the hull. Wiring is all secured every 6” and labeled at the beginning and end of every compartment.

ADVENTURESS will be launched in 2012 and join the ever-growing list of updated classic yachts now sailing with modern systems neatly hidden between the skins.

-Tom Kiley

No 3D Glasses Required

2012-01-05T06:08:00.003-05:00

How do you build all of the blocks for an 83’ gaff schooner without access to the machinist, the fabricators, or the boatbuilders (who are respectively already too busy, too busy, and way too busy to take on additional work before launch)? It’s a pretty tall order but we may have found a solution in steriolithography files, overnight 3D printing, multi-axis milling and computer numerically controlled (CNC) routers.

While we haven’t completed any blocks yet, stay tuned — the test run looks promising. The ash shells are made right down the road at Tim Marchetti’s shop. Tim uses a CNC router to produce parts to our design. We sent him a few boards of Ash and a 3D computer model of the completed block assembly.

He took it from there to generate a tool path for the CNC router to follow. It wasn’t more than a day or two later that Tim called to say that our parts were ready. The intricate shapes arrived complete with precision holes bored for the sheave axle pin, coin, and perimeter rivets. Each piece is a perfect duplicate and entirely interchangeable with the next. This should significantly reduce headaches and speed up the whole process come assembly time.

The bronze straps are going to be machined just a few miles from here, and while we never had any concerns that Richard Maxcy and his team could produce exactly what we needed, we did have some concerns about whether the parts from Knox Machine, Tim’s shells, and the sheaves being custom manufactured in Holland would all fit together once they arrived. We needed a way to test fit the metal parts and refine the design if necessary before committing to the significant expense of having all of those parts made. It turns out we’re not the first people to have this problem, and a pretty clever fellow named Charles Hull invented a solution in 1984.

The first 3D printers directed a very precise UV laser beam to a photo curable liquid polymer. These days it’s more common to use equipment that extrudes a hot thermoplastic or fuses individual granules of a special powder, either by means of precision applications of a glue binder, or again with a laser beam. Take your pick, the technology is pretty impressive. We used a company called Red Eye On Demand. It took longer to provide our name, address, and credit card details than it did to upload the 3D model of the metal part to the company’s server. Three days later the part arrived in a box.

Rockport Marine boatbuilder Tom Dayhoof took a box a parts down to the shop and assembled them into 3 blocks to see how long the process would take and test the accuracy of the fit. If necessary we’d have the opportunity to refine the design one last time before placing the order for the straps. But they fit like they were designed to go together, which of course they were.

-Brendan Riordan

Engineering Elegance

2011-12-20T06:01:00.002-05:00

Here in the design office at Rockport Marine we have the benefit and added pressure of working with 50 of the best boat builders you could ever hope to find. This means that when a design can be called genuinely beautiful and satisfies the pragmatic experience of that crowd we can claim a measure of success. It’s a pretty tall order so when we recently came across a new tool purpose built for engineering elegance we were keen to give it a spin. The restoration of Adventuress gave us the opportunity.

The spar loft here at Rockport Marine is a huge library of what works well aloft (and sometimes what doesn’t) but designing the rigging hardware for an 83’ schooner is a huge job and a few of the fittings warranted a more detailed engineering analysis.

When it came time to design the bobstay / kranze Iron attachment traditional rules of thumb described a fitting that was well, I guess the industry term is clunky. The challenge lay in optimizing the use of material to create an elegant fitting of appropriate strength.

Our new engineering program which dovetails with our current 3D modeling software allows us to specify the alloy of metal, apply loads to the part, and rapidly analyze how the fitting performs under load. All this means we are able to add metal where it is of greatest value to the strength of the part and remove it where it isn’t needed.

-Brendan Riordan

Shiver Me Timbers

2011-12-18T15:11:00.003-05:00

The 1936 L.F. Herreshoff ketch BOUNTY came to us on a truck from California in late November. Since being here she's come apart fast. Our initial work will include most of the backbone. BOUNTY had lost much of her shape, partly due to a line of scarf and butts in her plank keel and deadwood just aft of the ballast.

We will be attempting to regain some of her lost sheer as we replace her timbers. Unfortunately the deck is new and will fight this effort. We are lucky to have in stock some 38-foot Angelique for her plank keel and enough good white oak for her other timbers. Tim Watts has turned out quite a few new frame ends and floor timbers since last week.

-Sam Temple

A History Lesson

2011-12-18T08:47:00.009-05:00

Rockport Marine sits at the mouth of Rockport Harbor, on the west side of Penobscot Bay in Maine. It is hemmed in by a river on one side and a creek on the other, which both fill to bursting in the spring run-off. During that time of year, fishermen string large cone-shaped nets across these outlets to catch elvers, small eels that run up to spawn. The eels are thin and clear, and considered a delicacy in Japan, where they are shipped to and sold.

Before the boatyard was a boatyard it was a sail loft, a roller rink and a lobster processing plant, at different times. The Allen family bought the large, barn-red buildings and docks in the 1960s. On the ground floor, Luke Allen began repairing and storing wooden boats. His wife, Norma, started a restaurant on the second floor, serving solid New England fare: clam chowder, haddock with a cream and crab sauce, prime rib and meatloaf. The couple lived on the third floor with their four children, and could look out on the dooryard of the shop, the docks and moorings, and to the lighthouse on Indian Island at the mouth of the harbor. It is a deep harbor, with good holding ground, but exposed to the south, and can churn up like a washing machine in a southerly blow. In the summer, then, as now, it was packed with yachts and lobster boats.

Along the walls of the entrance are photographs of what Rockport Harbor used to look like. While it is now quietly bucolic, at the turn of the 19th century Rockport was a gritty, industrial harbor. Lime kilns blazed through the night, and a train ran from the quarries to the piers. Some faded photos show as many as 15 or 20 schooners docked and anchored, low to their waterlines with their freights of lime. Rockport was considered a poor cousin of Camden, and it was home for the people who worked in Camden’s shops and took care of Camden’s wealthy homes.

Now the yard is owned by Luke’s son, Taylor. The restaurant has become the office for the boatyard, which has grown and flourished under Taylor’s management. We use the old butter dishes to hold our paper clips, and the old bar is now the design office. When Luke started his boat business it had a handful of employees, and now there are 50 people building and restoring some of the most beautiful wooden yachts in the world.

- Maria Simpson