SC20-SD18

SAILBOAT DESIGNS

Two new designs for Scandinavian Cruisers

Scandinavian Cruiser 20 & Scandinavian Dory 18

The SC 20 Daysailer. This design is a shrunk-down version of the SYDI-designed SC 40.

Scandinavian Cruiser 20

After SYDI completed the preliminary design of the SC 40 in early 2009, Scandinavian Cruisers decided they should bring out a smaller boat first, one that was more affordable and easier to sell than a 40' boat, but that still had the same style performance-minded features. These included a long, narrow hull with generous overhangs, the free-standing wingmast rig, the lifting keel, and the lifting rudder. One has to be very careful about downward scaling because human beings don't scale. Therefore, the proportions of length, beam, draft, and sail area all had to follow different scalings, and that would affect the appearance of the boat--its sleekness, its overhangs, etc.--as well as its performance. The scaling and design was done in-house at Scandinavian Cruisers from SYDI's original layout of the SC 40. SYDI did not participate in this scaling down and development, and, therefore, we are not deriving any income from this boat since it technically is not an SYDI design. Be that as it may, the SC 20 has turned out very well. What follows is a description of the construction and performance.

PARTICULARS

Length overall 5.86 M

Length on the waterline 3.84 M

Beam overall 1.30 M

Draft (shoal), 0.35 M

Draft (keel down) 1.75 M

Displacement (to Dwl) 0.34 Metric Tonnes

Ballast 0.17 Metric Tonnes

Sail Area: Main 9.00 Sq. M

Jib 3.80 Sq. M

Total 12.80 Sq. M

Displ./(.01Lwl)³ 167.40

Ballast/Displ. 0.50

SA/Vol.^2/3 26.71

Fig. 2. SC 20 Sailplan.

Obviously, with same-size humans, the boom is proportionally higher, and to achieve appropriate stability, the keel is proportionally deeper. Some hull shaping had to take place to make sure the flotation was adequate to hold two people and still float on a reasonable waterline.

Fig. 3. SC 20 Deck Layout.

The beam also had to be wider to fit humans, to have adequate stability, and to fit your feet inside the cockpit and your butt on the side deck, all while the crew could handle the lines, tiller, and the keel.

Fig. 4. SC 20 sailing rendering complete with water and wake. This is done in a 3D file, so images can be saved from any point of view.

After 2D drawings and general laying out, SC's contract 3D artist, Leo Wu, took over and produced enough detail, with background, to show the SC 20 underway. A lot of construction and hardware detail was figured out during this stage. When this work met SC's satisfaction, the necessary files were converted to patterns for tooling, and an equipment list was compiled for fitting, ordering, and stocking the hardware.

Fig. 5. SC 20 hull plug with deck plug being fabricated in place at Red Dragon Boatbuilders in China. Hull and deck production molds were taken from these plugs.

There aren't any boatbuilding secrets here--this is conventional tooling and boatbuilding. The advantage, of course, is high-quality work at low cost. The owner of Red Dragon/Paramount Yacht Building Co. Ltd. is David Winter, an American with his business in Xiamen, P.R. China.

Fig. 6. The SC 20 hull #1 ready for the water.

This gives some real-life idea of the proportions of the SC 20. Note the Danish flag--the owner of Scandinavian Cruisers is Nis Peter Lorentzen, a Dane from a family of boat builders going back a number of generations, who has many business interests in P.R. China. The idea of the Scandinavian Cruisers, of course, is to bring traditional Scandinavian style and sailing performance back to the world market by using modern boatbuilding materials and techniques at a reasonable price. There is a world-wide sales network now set up to market the SC line of boats.

Just as a side note, I discovered on the Internet that the Danish flag, called Dannebrog, is the oldest state flag in the world still in use by an independent nation. When you live in St. Augustine, you are keenly aware of oldest this, oldest that.... St. Augustine, for example, is the oldest continuously inhabited European settlement in the United States, predating Jamestown, VA, by 42 years, and Plymouth Colony, MA, by 55 years.

Fig. 7. This is a pretty snappy little boat. Nis Lorentzen is out for the first sail on SC 20 #1 .

Now, in the spring and summer of 2010, the SC 20 is getting some independent reviews and sailing time with various sailing magazines and reviewers. Bob Perry said in his review of the SC 20 in the June 2010 issue of Sailing magazine:

This design is all about making a pretty vintage picture on the water. Along with that you get a type of performance not usually found on today's high-performance dinghies. I can easily see myself enjoying this boat. I could spend a lot of time in this boat. I'm willing to hike but I am not sure I would use the trapeze unless I was in an unusually good mood.

There is no small daysailer quite like this one, and that is why I like it.

Also, in the cover story in the July 2010 issue of Segeln magazine in Germany, reviewer Thorsten Hoge took the SC 20 out for a test sail on the River Elbe and experienced a real surprise--a Chinese Firecracker, as he called it. Of the many nice things he said about the SC 20, there was this in particular:

The open keelboat reacts very lively to the smallest steering inputs. This makes her a joy to sail. A real sailing pleasure. And the way she goes upwind... It's like a dream. Upwind leg after upwind leg follows against the current of the Elbe. Her pointing angle of attack is hard to measure accurately but could well be around 70 degrees. She tacks very fast. The narrow jib doesn't allow for much steering error. If you don't pay attention it will cost you speed right away. The narrow yacht needs some heel, the bow lifts somewhat and more lift to windward is achieved. This is a real difference compared to the wide hulled modern boats, which tend to be over-trimmed on the nose when heeled.

I think his statement about her pointing angle of attack being 70 degrees means her pointing angle from tack to tack. This is excellent and as hoped. That means she is sailing 35 degrees to the wind, unheard of in the vast majority of modern day boats, and maybe seen only in the America's Cup or perhaps the Volvo Round the World boats. The bow lifts as the boat heels. This is as intended, and is truly an unusual characteristic in modern yacht design, although it was quite common a hundred years ago. Until recently, in my opinion, modern designers had lost the art of how to do that. Here, we have it back. This is similar to other designs I have done in the last few years, for example, the owner of Saint Barbara is reporting similar performance and tacking angles.

Mr. Hoge concludes his sailing review with:

Scandinavian Cruisers set out to build the fastest possible daysailer with classical lines. I think that they succeeded. Real sailing pleasure combined with high build quality. Wet when the conditions are very choppy but still very comfortable to sail. A real Chinese-Firecracker.

Thank you, Mr.Hoge, for your report.

Well, if I haven't lost you yet, there is still another new boat from Scandinavian Cruisers, namely, the new:

Scandinavian Dory 18:

The Scandinavian Dory 18. This rendering is the two-person rowing configuration; it also has a sailing rig.

The Scandinavian Cruiser sales agent in Australia proposed the idea for building a sailing and rowing Whitehall, to be built in a lapstrake design in fiberglass. SC approached me about the design, but the up-front design cost was a little beyond their budget. Searches through the market revealed already-completed designs, some with patterns, for as little as $100. Sorry, I can't design such a boat and provide construction drawings for even $1000, so I suggested that SC contact one of those designers and see if they could secure a production build and marketing deal. This they did, and secured an agreement with Roger Long in Maine for his 18' lapstrake dory design. Roger is a specialist in oceanographic research vessel design, and he has even dived down to see the Titanic. Website: www.rogerlongboats.com. He provided the hull plans, and I was hired to design the rig and the daggerboard and rudder blades. The next figure shows SC's concept sketch at this stage:

Fig. 2. This is the arrangement of the 18' dory, soon to be called the Scandinavian Dory 18, drawn by Nis Lorentzen.

The concept of the boat included these targets for design and performance:

Classical elegance and speed of the Whitehall boat with modern boat technologies and flexible day boating functionalities.
A stable, yet fast, “wolf in sheep clothes” sailing boat with rowing capabilities.
Include a swinging daggerboard and kick-up rudder for shallow water access and easy trailering.

The daggerboard had to be very narrow and deep in order for it to stow up in the hull fully below the cockpit deck while at the same time have enough profile area to counteract the drive from the sail. SC did not want a daggerboard casing cluttering up the cockpit. In addition, the rudder blade had to be of the same blade section as in the daggerboard in order to simplify tooling. This also works well for sailing capabilities. Because of their shape and size, carbon fiber construction was necessary for the blades. We were going to use carbon fiber in the rig anyway, so its use in the blades was a natural extension.

PARTICULARS

Length overall 5.35 M

Beam overall 1.30 M

Draft (shoal), 0.17 M

Draft (keel down) 1.28 M

Displacement (to Dwl) 85.0 Kgs

Sail Area 10.0 Sq.M.

Like the SC 20, the rig had to be simple to put together while the boat was on the trailer, it had to be fast and easy to sail and at the same time not look out of place on this traditional hull. I think we are really trying to re-invent tradition here, because the best rig for ease of sailing and performance is--of course, my specialty--free-standing with a half-wishbone rig. So we went back and forth on the sailplan and ended up with this final design:

Fig. 3. SD18 final Sailplan showing her modern rig and appendages.

I developed the rig and appendages in ProSurf, my NURBS surfaces modelling program, converted them to iges and Rhino files, and sent them to our 3D artist in China, Leo Wu, for rendering. I was responsible only for the blades on the daggerboard and rudder, and Roger worked out the geometry of the heads of the blades for fit to the hull and their deployment hardware. Then Leo married the details together in his modelling program and came up with the final renderings to Roger's and my liking:

Figs. 4 and 5. These are computer renderings of the final design of the appendages, daggerboard (left) and rudder (right)..

Similarly, the rig was subcontracted to a spar builder. The mast has a constant diameter (no taper) below deck level, and it has a straight taper above deck level. This is the easiest shape to build. Some taper is necessary for proper mast bend, which in turn, establishes the sailing characteristics of the rig. The boom, on the other hand, is quite complicated in that it is curved in two dimensions in a half-wishbone shape and then again in the third direction with a radius curve opening upward. I am not exactly sure how this is going to be built, but that is what SC wanted, and they and the spar builder are figuring that out.

It is important, too, that all the hardware fit the human form, and in the picture below, Nis Lorentzen is getting measured for the rowing hardware. A younger woman who had a smaller frame was also used to help position the hardware at alternative limits. This, again, is conventional boatbuilding--you have to know where the hardware going to go so that rigid inserts in the laminate, if necessary, can be placed precisely on each and every boat. Also, if bosses are needed to be molded in place to fit specific hardware, this has to be known during the plug-building stage.

Fig. 6. SC's Nis Lorentzen assists in the placement of rowing hardware while a Red Dragon builder marks positions and takes dimensions.

In the end, we end up with 3D renderings which are sent out to the dealer network, advertising outlets, and reviewers prior to the first boat hitting the water. At this writing, the SD 18 is still under construction, but it should be making its debut at the fall 2010 boat shows in the US, Europe, and Down Under.

Fig. 7. The SD 18 in her sailing configuration. The background and water have yet to be added.

Just to prove that the real life boat actually exists, here are some photos for rowing and sailing:

Fig. 8. Nis and his wife Lily and son Maxi out to test the ease with which this fiberglass-carbon-Kevlar boat can row.

Fig. 9. The carbon fiber free-standing rig and appendages help the SD 18 fulfill its destiny!

For more information on the SC 20 and the SD 18, you may also visit the Scandinavian Cruisers website at www.scandinaviancruisers.com. You may also contact us through the Contact Us link below.