Globetrotter 45

SAILBOAT DESIGNS

THE GLOBETROTTER 45

The Globetrotter series of yacht designs from Sponberg Yacht Design Inc. was born during the 1990-91 BOC Singlehanded Race Around the World. I felt that a cat-ketch wingmast rig on the appropriate hull would have a number of tactical and safety advantages that no other conventionally rigged boat could possibly have. From the early publicity of the Globetrotter open class 50 and 60 designs came Project Amazon, an open class 60 that was launched in 1997 and participated in the Around Alone Race in 1998.

PARTICULARS

Loa:                            45’ 0”                                       13.715 M
Lwl:                             41’ 2”                                       12.496 M
B:                               14’ 0”                                         4.267 M
Design Draft:                 6’ 6”                                         2.016 M
Displ:                       30,100 lbs. at Dwl (less 3")            13,657 Kgs at Dwl (less 75mm)
Ballast:                     12,000 lbs.                                    5,445 Kgs.
Sail Area:                 1,292.8 sq.Ft. (including masts)     120.09 sq. M
Wetted Surface            562.0 sq.Ft. (w/ rudder)                50.32 sq.M

Cp (hull w/ keel) 0.514

Cp (canoe body) 0.603

Displ/(.01Lwl)³ 192.70

SA/Vol^2/3 21.38

SA/WS 2.30

AVS 137°

STIX 52.276 (satisfies ISO Category A)

FEATURES

Aft cabin with aft T-cockpit
Pilot house with inside helm, large chart table, and full-length berth
Scoop stern with radar arch and dinghy hoist
External lead ballast with bulb
Cat-ketch rig with free-standing carbon fiber rotating wingmasts (ketch rig optional)
Carbon fiber rudder and stock
54 hp Yanmar 4JH4CE 4-cylinder diesel with saildrive below pilot house sole
Large well-equipped U-shaped galley
Large head with separate shower and wet locker
Main saloon with fireplace, stowage and bookshelves outboard of the settee berths
Forward cabin with V-berths (upper/lower twin berths optional)
Construction possible in composite, wood-epoxy, or aluminum

The Globetrotter’s proven design features for short-handed open water ocean racing also apply directly to cruising sailboats, which are generally sailed by just a few people, crossing oceans, and generally meeting the same weather and circumstances as the open class racing boats. I wanted to combine the wingmast cat-ketch rig with a suitable hull for carrying people on long voyages, such as I hope to do in my retirement.

Some of the features I would like on my next boat include a pilot house, an aft cockpit, and an aft cabin. When my wife, Arliss, and I were sailing Duprass, our Bianca 27, from England to California, we discovered we sorely missed not having a pilot house, such as we had seen on other cruising boats. It keeps cool and inclement weather off your back, especially during night watches, as well as the hot sun out of your eyes and off your head during the day. And on long voyages, you really do need inside steering in addition to normal outside steering.

I like an aft cockpit because it gives you a full view of the boat when underway. Mid-cockpit boats are nice, but they necessarily split the accommodation in two (which might be OK for some, giving better privacy to the after cabin), but you also have a lot of boat behind the helm as well as in front. Therefore you have to pay attention to your boat in two directions, whereas, in an aft cockpit boat, you are really looking in one general direction during maneuvering—forward. An aft cockpit also gives you more direct access to the stern, and I like a scoop stern platform for easy boarding to and from a dinghy. Finally, the aft master cabin has to be big enough for a double berth with standing room next to it. Many aft cockpit, aft cabin boats squeeze a double berth under the cockpit seats, but you have to get into the berth over its front end, which requires a fair bit of contortion of your body to do. Far better to be able to get into the berth from the side—it’s more comfortable and more like home.

The real trick comes in trying to get all of this into a hull less than 50’ long. If length were of no concern, it would be easy to pack all of these features into a livable space. But I have to admit that as I get older, the thought of paying for and maintaining a 50’+ boat is beyond my financial means. But more importantly, I realize my strength is not what it used to be, and I need something that is easy for my wife and I to handle. Even at 45’ this boat is plenty big and will require more than a pauper’s purse to build. I intend to make good use of electric winches and windlasses to assist in the heavy work of operating the boat.

Over the years I have tried to get these features into a 38’ hull, then a 42’ hull, but there was always something a little cramped with these designs. I have now expanded the length just a little to 45’, and everything works well in the Globetrotter 45.

Recognizing that not everyone is convinced of the efficacy of the wingmast cat-ketch rig, the next best alternative is a cutter-rigged ketch, so I have drawn an additional sailplan for the Globetrotter 45. Some people will say this looks more like a real sailboat, not “funny looking” as some have described cat-ketches. A ketch rig makes a lot of sense for cruising because it splits up the sails into smaller, easily handlable areas. It gives you greater versatility in matching sail area to the conditions at hand. Ketches are very popular rigs for cruising.

GENERAL ARRANGEMENT

Cockpit

The business end of a good cruising sailboat is its back end. This is the most convenient place to board and disembark from the boat. It is where all the control happens—maneuvering, navigating, and general sailing operations. It has to be ergonomically correct, it is the site for an array of equipment, and it has to protect the occupants.

T-shaped cockpits have proven a very workable helm arrangement. You sit at the back end of the boat with it all before you. The pilot house is not so large that it blocks your vision forward. With plenty of windows, inward canting sides, and generous camber to the top, visibility is very good. As many cruisers do, you can also install jump seats in the stern pulpit to lift you up even further for greater visibility.

The radar arch on the cat-ketch is for mounting the serious electronic gear—radio, radar, and satellite communications antennae, as well as the stern navigation light. The hoist for a 10’ hard-bottom inflatable is fixed to the cross platform. The drawings show the dinghy just out of the water. When underway, the outboard motor can be hoisted off and the dinghy tilted up and forward and clipped to the side uprights of the arch. This places the bottom of the dinghy towards the oncoming following seas when sailing downwind, and so prevents the cockpit from getting swamped by a boarding sea.

The aft bulkhead of the pilot house is recessed a good distance forward so that there is seating within the protection of the pilot house sides without having to be totally inside the pilot house. This is a most comfortable place to sit when it is drizzly outside, or the sun just too intense. The sheet winches can be tailored to the owner’s wishes for size and type, but I would prefer self-tailing electric winches with sheet stoppers as necessary for holding lines. The canvas dodger can completely enclose the cockpit thereby making another totally enclosed space in inclement weather, even while under way.

Access to the machinery and stowage spaces below the cockpit is through the cockpit seat lids. Under the center helm seat aft is access to the rudder head and steering. An emergency tiller can be fitted through the seat opening if necessary. The rudder and stock are made of carbon fiber for high strength and light weight. Cable steering is shown for those that prefer it, but closed-circuit hydraulic steering, particularly with two helm stations, would be the most desirable. The side cockpit access lids are part of the seats themselves as well as the seat backs—one-piece construction. This provides a huge opening, fully scuppered, in which to step below.

If you want gas cooking on board, there is a gas locker on the port side of the “T” in the cockpit underneath the port aft winch. This locker would be vented and drained aft to the scoop stern, and the gas supply would run forward to the galley stove/oven on the port side. Appropriate shut-off valves and controls would keep the gas system closed when not in use.

Pilot house

Inside the pilot house, the second steering helm is to starboard and the chart table with the electronics suite is to port. The helm seat with a removable back rest is actually the forward end of a full-length berth that extends under the starboard cockpit seat. Want to lie down while on watch, just slip your feet back along the berth and grab a few Zs. The best rest comes when you can lie down fully, not when you are slouching in a chair.

The chart table to port in the pilot house has enough space for stowage of charts in the drawer, and the console can be arranged with whatever electronic navigation gear the owner desires. This space can be customized to the owner’s wishes. The remaining space under the chart table and console provides headroom to the master cabin below.

The pilot house sole has lift-out sections and lift-out steps for complete access to the Yanmar 54 HP diesel sail drive. These are tremendously compact installations that require the minimum of maintenance because the shafting is self-contained. There is plenty of room in the machinery space below the cockpit and aft of the engine to put a water maker and water heater, the batteries, and even a generator if the owner wants one.

Master cabin and head

Going down the few steps from the pilot house to the main cabin sole, you step through a door to port to go into the master cabin. The full-size double berth is outboard, and a window in the hull provides adequate light. If you want more light, deck prisms do the trick nicely. There is plenty of clothes storage under the berth, and on the forward bulkhead can be a hanging locker or shelves as shown, Another shelf is inboard of the berth on the longitudinal bulkhead.

Opposite the master cabin to starboard is the head and shower in separate compartments. The shower has a separate door so that you can reach the wet locker outboard of the shower stall. The wet locker and the shower drain are common, and if you want to install separate heating and drying to the wet locker, that can be arranged. The forward compartment of the head has the toilet and a sink. All gray water drains go to a gray water tank, and the black water drain goes to a black water tank. Gray and black water drainage will be through deck openings to appropriate shore-side facilities, or by Y-valve and pump overboard when offshore.

Galley

The galley has loads of storage above and outboard. A gimbaled stove/oven is outboard, surrounded by stowage under the side deck. On the aft side of the galley is a countertop with stowage below and more cabinets above. On the forward side counter is a refrigerator, either a stand-alone, under-counter unit, or if the owner prefers, a built-in cold plate installation. A double stainless steel sink is located near the centerline, and there are more cabinets over.

Main saloon

It’s a saloon, not a salon. A saloon is the main social cabin on a boat. A salon is where you get your hair or nails done. A lot of people still get these terms confused. The Globetrotter 45’s main saloon is fairly conventional, but a design that works. The settees are long enough, 7’ 0”, to double as sleeping berths, and there is plenty of stowage under and behind them. Cupboards above and behind are located at the ends of the settees, while bookshelves are in the center port and starboard. The center sections also have hull windows in them for additional light into this space, as well as view outboard. At the aft end of the starboard settee is a fireplace that can burn charcoal or be diesel fired. This keeps the boat warm and cozy in cold climates.

Forward cabin and fore peak

The front end of the accommodation includes a V-berth as shown. As an option, over/under bunks could be provided one side, with a hanging locker and a seat on the other. Shelves are outboard of the V-berths, and more cabinets are located on the forward bulkhead. The fore peak is where the two electric Maxwell V-1200 vertical axis anchor windlasses with gypsy heads are located, and a hatchway in the bulkhead provides access. The anchor chain falls are through chain pipes into the central space below the V-berths. A central divider in this space keeps the all-chains ground tackle separate. The anchors shown on the bowsprit platform are a 44-lb. Bruce to starboard, and a 22-lb. Bruce to port. CQR plows could be provided as an option. The stub of the forward mast on the cat-ketch, or the inner headstay chainplate on the ketch, are also in this fore peak space.

Keel

Shoal draft is important to a lot of cruising people, and on a boat like this, a draft of 6’ 6” is fine. I show a well-defined keel that is long enough to support the weight of the boat as she sits on the hard, and I concentrate the lead ballast into a bulb casting. The bulb gets the weight down lower for generous stability, and the bulb doubles as an end plate to keep the flow on the keel and the tip vortex and induced drag to a minimum. Keel bolts come up into the stub, and access to them can be between the tanks that would be mounted below the cabin sole port and starboard. In wood-epoxy construction, there would be deadwood above the ballast casting, making the sump spaces somewhat smaller. The deep sump under the engine could have a separate lift-out pan to catch and drain engine oil. Note that a water and oil tight bulkhead separates the engine sump with the main accommodation sump. Bilge pumps would be located in each of these spaces.

THE CAT-KETCH RIG

For those still not convinced, I would like to explain again the reasons why I like the cat-ketch rig. To begin, I first have to explain the disadvantages with a conventional stayed rig:

The headstay and backstay define and confine the shape of the sailplan to a triangle. A triangle is the absolute worst possible shape you can conceive of to be a lifting foil. Why? Because in order to be its most efficient (high lift with low drag) the top of a triangular sail necessarily must twist to windward. This is impossible to achieve, and so you are forced to accept much higher induced drag (drag that is always created with lift) which creates high side force pushing the boat sideways instead of drive force pushing the boat forward.

The rigging is expensive to maintain and provides no lift. It produces only parasitic drag (drag with no corresponding lift).

Every individual and separate part in the rigging is a potential failure point. Lose one small part through breakage, corrosion, or just falling out of place, and the rig is almost guaranteed to go over the side.

A stayed rig is naturally unstable downwind. This is because the boom cannot go farther forward than the after lower shrouds, and such a boat running downwind naturally wants to round up into the wind. In a heavy seaway, this can cause an uncontrolled gybe and/or broach.

A cat-ketch rig totally eliminates these four big disadvantages. Without headstay and backstay, the fore and mizzen sails can be any shape--elliptical, square-topped, anything, whatever is most efficient--without the worry and wear and tear or chafe. These sails are elliptically shaped. Without the rigging, there is no parasitic drag. Without the rigging, there is nothing to fail. If it is not there, it cannot break. And finally, a cat-ketch rig sailing downwind can be set with the booms forward of the beam, wing-and-wing, with the masts turned aft facing into the wind. Sail shape is superior, creating generous lift which is much more powerful than the drag-only air flow of a conventionally stayed rig where the main is squashed against the spreaders and shrouds. There are no wires restricting the movement and positions of the booms.

The cat-ketch set wing-and-wing can’t gybe uncontrollably. If it tries to, one of the sails naturally pulls the boat back downwind. To come about, you simply pull both booms back to an aft position and tack in the normal way. You can gybe the boat if you want to; gradually pull the booms around and let them fly to the other side where they gently come to a stop as they spill the wind. The gybe is gentle, not shocking. You don’t have to worry about the boat broaching or the boom breaking across the leeward shrouds—the shrouds are not there.

For a boat of about this length (in the realm of 40’), a free-standing cat-ketch rig becomes more economical to build than a stayed rig. I would expect each mast to cost $35,000 to $40,000, so $70,000 to $80,000 total. As a percentage of the total boat cost, expected to be about $500,000 to $700,000, this is roughly 10-15% of the total, about average for any boat.

The weight of the masts would be about 300 lbs. each, which works out to about $100/lb. per mast. Construction of the masts can be done by a professional mast builder, by the boatbuilder, or if some intrepid soul wants to build them himself or herself, that is certainly possible. Back in the early 1980s, I developed a method of construction for free-standing masts in which a wood-epoxy shape is built first, and over this is laid the carbon fiber laminate. I have had masts built by this method in the US, Canada, and New Zealand. The method of construction is described in Professional Boatbuilder magazine, issue 14, Dec/Jan 1992, featuring the design of the wood-epoxy/carbon fiber wingmast on my Delft 25 design. More information about free-standing masts and wingmasts, along with some actual examples, can be seen my website, www.sponbergyachtdesign.com.

The center of gravity of a cat-ketch rig is generally a little lower than that of a stayed rig because most of the strength (diameter and wall thickness) is built down low where it is needed the most. The mast diameter and wall thickness both taper uniformly to the masthead. The center of gravity of the mast is roughly 35-40% of its height. In a stayed rig, the mast is almost always a constant cross-section and wall thickness throughout its height (except for any taper at the top end), which means that the center of gravity will be about 45-50% of mast height. The same applies to rigging--heavy stainless steel of constant section and weight. Its total weight, like the mast, is centered near the mid-height in the rig. As a result, the stability of a boat with a cat-ketch rig is improved over an identical boat with a stayed rig.

Another neat benefit of the free-standing cat-ketch rig is that the masts can be sealed nearly completely, adding a tremendous amount of buoyancy to the boat in case of a knockdown. Whereas a conventionally rigged boat with its heavy metal mast still has a negative area under the far right end of the righting moment curve, a cat-ketch with buoyant, nearly air-tight masts gains so much buoyant lever arm when they hit the water in a knockdown that it completely eliminates the negative side of the righting moment curve.

Despite all these neat, nifty features, most people still cannot get used to the idea that no wires hold up a free-standing mast. To those people I say, “Do you ever fly, you know, like in an airplane?” (Most people have.) Then I say, “Well, the next time you fly in a 747, maybe you’ll want to rig up some wires from the fuselage to the wing tips to make sure the wings stay on. Come on! A 747 weighs 850,000 lbs., flies about 7 miles above the earth, at over 500 miles per hour—and it doesn’t have any wires holding the wings on! Airplanes got rid of wires over 80 years ago. It’s time sailboats did the same!

Still unconvinced? OK, you can have a ketch-rigged Globetrotter 45. I promise I won’t be upset.

If any of you would like to have a Globetrotter 45 for yourself, please contact me, and we can see about doing the complete boat design and getting one built for you. Ultimately, I would like to get this design into production so that I could buy one for myself. I call this a Globetrotter because that is what I want to do with it--trot the rest of the way around the globe.

Eric W. Sponberg

Naval Architect, PE (CT)