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Celebrating Eleven Years Online...!
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The 96' Sailing Yacht"ZEBULUN"
Sail Plan | Accommodation Plan | Deck Plan & Sections | Structural Perspective | Hull Form | Lines Perspective Copyright 2001-2007 Michael Kasten
The Name Zebulun - also spelled Zebulon or sometimes Zevulun - was one of the ten lost tribes of Israel who were conquered and then driven out of the northern lands of Israel in 721 BC by the Assyrians (sometimes claimed to be the Babylonians). The original home of the tribe of Zebulun is now southern Lebanon - to the west of the Jordan River in the region of the Litani River. After having been driven from those lands, the Zebulunites, along with their brother tribe the Naftali also from that same region, subsequently occupied lands throughout what is now Afghanistan and Pakistan. Today, per scholars of these matters, a small group of Zebulunites in Bombay, India are possibly all that remains of the lost tribe of Zebulun.
General Concept Zebulun was designed as a highly capable long range, fast and safe offshore sailing vessel in aluminum. The original intent was that Zebulun be capable of doing rescue work, mission work, and relief supplies delivery for troubled areas. Long range under power was also a primary requirement, thus one could legitimately refer to this as a true motor-sailor, with 100% functionality in either mode. Zebulun's lines are intended to provide a high performance, easily driven hull for maximum speed and the fastest passage times. As such, Zebulun will also make an exceptionally fine charter vessel. Hull Particulars are as follows:
As we can see from the above, Zebulun is of nearly “ultra light” displacement. Displacement will vary from around 195,000# when lightly loaded, to a maximum capacity of 259,000# with tanks full, stores for twenty people, and the boat ready for a long passage, or alternately loaded with a cargo of supplies.
The cabins have 6' 8” headroom throughout the main cabins - at the centerline. For the sake of headroom in the aft cabins, the exterior deck aft is raised to the height of the top of the main bulwark. Where needed, headroom pockets have been created within the cockpit structures to permit standing headroom in the aft master and guest cabins. Forward, the deck is surrounded by substantial bulwarks for maximum safety. Aft, the deck is surrounded by a toe rail for security. Although not detailed as such on the drawings, the decks are additionally protected by a 36" high welded bow pulpit, stern pulpit and welded stanchions and lifelines along both side decks. For additional safety there are welded aluminum hand rails along each house top. A hard "Bimini" top is provided above the forward part of the cockpit, with windows opening forward. This was an originally requested design feature that works out rather well, however if a soft dodger were preferred - so be it...! For anchor handling, a pair of hydraulic vertical axis windlasses are located forward, with stout mooring bitts located on either side of the foredeck. Additional mooring bitts are placed on both side decks and on the after deck, three per side. Additional smaller bitts and cleats are provided as needed.
Construction Materials Zebulun has been designed according to the scantling requirements of the ABS Rule. Aluminum has been chosen as the material for hull, deck and house structures for the purpose of extreme ruggedness, for ease of construction, for its very favorable strength to weight ratio, the goal being to permit a greater reserve capacity to carry cargo or passengers. Interior materials have been chosen to be as light in weight as possible, while not being overly expensive to construct. For any of the larger flat panels where it will not increase the joinery labor to any appreciable degree, honeycomb panels are used.
Interior Arrangement For her originally intended mission and rescue work, the accommodations aboard Zebulun have been designed to provide comfortable living for two to six crew aft, plus twelve or more passengers forward during extended passages. Additionally, there is a large “Great Room” amidships for the purpose of comfortable lounging for passengers and crew; for the purpose of carrying more passengers on shorter voyages; and for stowage of cargo being delivered on rescue or supply delivery missions. This layout is perfectly suited to chartering as well. The layout could easily be changed to suit a newly defined purpose. For example, if so desired the amidships lounge could be differently configured. It is really quite large, so the possibilities are many. I will describe the interior spaces of the Zebulun via the following “walk through” (also see the layout images linked above). Beginning right forward, a spacious forepeak can be entered through a deck hatch and ladder. The forepeak is intended for sail and line storage, and also for the anchor rode. Aft of the forepeak are a pair of generous head compartments, one to port and an identical one to starb’d. Each head has a shower, a vanity cabinet with a sink, a toilet and a small dressing area. Aft of the forward head compartments are six separate guest cabins, each able to house two passengers. The forward pair have two single berths each, the central and after pair of these forward cabins have a double berth and a deployable overhead berth, possibly for children. Each guest cabin has a vanity cabinet with a sink, a separate bureau/nightstand for personal effects, plus generous storage in drawers below the berths. Amidships in the vessel is the “Great Room” which is being referred to alternately as the “Saloon” per yachting terminology. The Great Room has the flavor of a library or reading room. Long settees with tables are placed as shown in the drawings. Outboard, there are long settees on both port and starb’d sides, having storage cabinets and bookshelves outboard. The “Great Room” serves multiple purposes, as described, including the ability to accommodate various cargoes such as food or medical supplies for rescue work. Storage is provided below the Great Room sole, as available after placement of tanks and structure. Aft of the Great Room and down a small stairway outboard both to port and to starboard are two small low headroom spaces. One is an office, and the other is a laundry room. These spaces are situated ideally for carrying cargo as well, being more or less centrally located in the ship. Between these two low headroom spaces is the engine room, accessed from aft. Aft of the Great Room and up a stairway is the Pilot House, containing the Pilot’s Seat; Helm; Navigation Area to starb’d forward; the Galley to port aft; and three separate Dining Areas arranged as shown on the drawings. The central portion of the pilot house sole is lowered in order to provide headroom to the walkway leading forward to the Great Room. The wheel house sole has thorough sound insulation to attenuate engine noise from the engine room below, as is further detailed in this specification. The "dashboard" area forward of the wheel holds navigation instruments. Immediately forward of the helm is a cabinet housing the helm controls and the engine controls. A magnetic compass is mounted prominently forward of the wheel. A radar and sonar screen are located within easy view from the helm. A VHF radio is mounted near the helm. Other navigation instruments may be mounted overhead as needed. The helm seat swivels to allow use as a chart table seat. Aft of the Pilot House, on deck, is located the cockpit and exterior helm. Aft of the Pilot House, inside, and down a stairway is a hallway, from which one may access the after cabins below the cockpit area, the engine room, and a centrally located Head. This aft head is intended to serve the aft cabins as well as being a “day head” for the crew. The head contains a vanity cabinet with sink, a toilet, and a large shower. The after cabins are arranged as follows: A crew cabin is located to port forward and contains a double berth outboard with a deployable berth for a child above. This cabin contains a bureau / night stand, as well as a vanity cabinet with a sink. A second crew / guest cabin is located to port and aft, and will contain a double berth toward the center of the vessel and aft against the transom. A long counter is located outboard, and will have a sink at the forward end, and a hanging locker at the aft end. A “Dutch door” will lead aft through the transom to the swim platform. The master’s cabin is located to starb’d aft. A double berth is located inboard and aft, and will have a settee outboard with a small sideboard / end table at each end. The forward end of the cabin has a hanging locker inboard, and a doorway to the master’s head outboard. The head has a vanity with sink, a toilet and a shower stall with a seat. Descending the stairway aft from the Pilot House one emerges into the aft hallway. From this central hallway, one may turn immediately forward again and proceed down a few steps to a door leading into the engine room. Passing into the engine room, one may access a tool room / workroom to starb’d, and a pantry / storage room to port (located below the galley).
Other Possibilities...? The interior layout allows the vessel to be used in sevaral modes: By "managed ownership" we mean that the yacht is privately owned, but is managed by a charter company who is able to charter the vessel when it is not being used by the owner. In exchange for its use, the charter company takes care of the vessel's maintenance and repairs, and provides the owner with an income stream. Done correctly, this is a rather ideal way to own a boat - no maintenance, it pays its own way, and the owner can step aboard a well maintained vessel nearly any time and simply enjoy their time aboard rather than having to manage the vessel's upkeep.
Power & Range The engine space, located below the Pilot House, is thoroughly sound proofed, and has a forced ventilation system. Low levels of noise and vibration are provided via adequate sound insulation and vibration damping. There are flexible engine mounts and a flexible coupling on the shaft. There are two fresh water cooled Cummins 6CTA 8.3-M marine diesel propulsion engines. Using a continuous duty Marine rating, the engines provide 255 hp each at 1,800 rpm. Autoprop propellers are used. Shaft rotations are opposite. Long range cruising speed for this vessel is between 10 and 11 knots. Per the typical Beebe method of calculating average range in ocean conditions, range is approximately as follows: At 10 knots, range should be around 3,400 NM. At 11 knots range should be around 2,700 NM. At 12 knots, range should be around 1,600 NM. Displacement hull speed per the traditionally applied limits is around 13 knots, however due to the relatively light hull form, maximum achievable speed for Zebulun is around 17 knots while motor sailing, or given the right conditions, under sail alone...!
The Rig Zebulun is given a three masted schooner rig in order to make use of relatively high aspect individual sails, while keeping the rig to a conservative height overall, and individual sail sizes within manageable limits. Sails are fully battened to enable the use of a large roach and an elliptical plan form, while still allowing maximum draft control. The two forward sails are identical in size and construction, and the mizzen slightly smaller. The sails are each cut differently in terms of draft in order to take maximum advantage of their relative positions in the rig. There is one large roller furling jib on an inner forestay, and there are two other light weather stays’ls set from the respective mastheads.
Standing Rigging The masts are each be identical in terms of their layout, with the exception of the amount of bury belowdecks, and with the exception of the height of the mizzen boom. The masts and booms are constructed of 6061 T-6 aluminum pipe. All spars are welded shut in order to be air and water tight. Halyards are external. Reefing is slab type with hydraulic winch assist. The rig is supported by swept back spreaders, making use of a single lower shroud, and a single upper shroud per mast per side. There are running backstays at least on the Mizzen mast (other locations to be determined.) Wire is 1 x 19 type 316 stainless throughout, except for the running backstays and the jib's internal luff wire, which is 7 x 19 type 316 stainless. Turnbuckles are one size larger than the wire they serve, and are fitted with toggles. Wire terminals are poured sockets throughout.
Running Rigging & Deck Hardware All running rigging lines are pre stretched braided Dacron line. Blocks are by Harken or equal. Halyards terminate on belaying rails at the base of each mast. Sheets are led to the cockpit area. Winches are by Maxwell or equal. There are two halyard winches per mast, one on each side at a convenient height. There are three sheet winches per side per side to handle the jib and stays’ls. Sheet winches are located in the cockpit area. For the boom sheets, there are Harken or equal roller bearing travelers, arranged to be at the full available width. Sheets are located within the outer 20 percent of the booms. There is a downhaul at the gooseneck of each boom. Reefing gear is provided for two reefs in each of the sails attached to the masts. Mast hardware is by Harken, and includes Harken roller bearing luff track and cars, Harken gooseneck, Harken roller furling gear for the jib, and Harken boom hardware.
Sails The Foresail, Mainsail, and Mizzen are fully battened. They have a large roach and are loose footed. Headboards are provided, as drawn. Sail cloth is stabilized Dacron or better. Battens are solid round or rectangular GRP extrusions, sized to suit the loads. Battens are attached at the forward end to Harken cars designed for the batten loads. The Fore, Main and Mizzen each have two reefs. The jib is roller furling. A storm jib is provided. A genoa or cruising spinnaker may be provided (to be decided). A pair of light weather stays’ls will be flown from the Main and Mizzen mastheads, set flying and attached at the deck to weather of the next forward mast.
NC Cutting Hull and superstructure surfaces have been computer modeled and faired. For the sake of saving considerable labor during hull fabrication, the structure have been detailed for NC Cutting via our usual CAD Design Stream. Frames, girders, keelson, stem, engine beds, tank faces and tops, and all hull plating are all detailed and nested, ready for plasma or water jet cutting. All frames have limbers and long’l cutouts. All components are nested onto separate plate sizes, as required by the cutter. Images of the NC files and the resulting structure can be seen in the following links:
In Conclusion At 96 feet, Zebulun is an ambitious project. A delight to sail, Zebulun is also a true "passagemaker" under power. With twin ballasted keels, Zebulun is capable to windward even with relatively shoal draft, and can sit on the hard when the tide goes out. Being of all aluminum construction and unpainted except below the waterline, maintenance requirements are minimal. With generous accommodations, Zebulun will be a fine host to the many who chance to sail on her. Sail Plan | Accommodation Plan | Deck Plan & Sections | Structural Perspective | Hull Form | Lines Perspective |
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