Wilbur the Wisp
Low Impact Coastal Power Cruiser
Container Transportable Design by
Jeff Gilbert

Note: Jeff Gilbert, designer of Hot Chili, entered a design contest at
He did not win, but has allowed us to view his entry
Honda OB -
50hp - 15kts
Beam WL
130hp - 25kts
225hp - 33kts
Diesel OB -
36hp - 13kts

The dream of voyaging overseas rarely includes a long slog across a moody ocean to get there. Furthermore optimum watercraft for overseas coastlines differ vastly from those required to safely get there. Long range motorboats are neither nimble nor beachable, blue-water sailcraft have deep draught & multis are clumsy & expensive to berth. The possibility of arriving exhausted, in an unsuitable boat needing unavailable parts, keeps would-be-Voyagers home in droves. Besides, few with the money have the time to cross oceans.

Wilbur covers the hard miles on a container ship, arriving in pristine coasting condition. Wilbur is a “Low Impact Cruiser” –a holiday home moving swiftly & quietly, without a huge displacement wave disrupting those same sensitive land-water interface environments which afford the most beautiful of views.

Wilbur can be craned from the water to a flat surface, and then pushed/winched into a standard 40ft container on 3 steel protected keel points. Only preparation is lowering the windscreen & radar mast, & raising the engine.

Wilbur fits a road/rail flatbed, & is legally trailerable. Holidaymakers can freight the boat ahead to a suitable launching facility. Return trips may be eliminated, time pressures eased Plan changes need not entail abandoning the boat overseas.

Even short hauls are < $US1 per mile, San Francisco or UK to Indonesia is under $US3000, and the longest trips on the planet are $US5000. Insurance is negotiable & optional, & compared with steaming risks, probably unnecessary.

For the commercial builder, export costs become a viable fraction of product value.

Plans show a minimal fitout for a small group to cruise in uncluttered comfort. Twelve-volt electrics are: safety, deck & interior lighting, CD & radio, sounder, radar, GPS, anchor winch, bilge pump & a small fridge when an icebox can’t cope. Deep-cycle gel batteries charge by motor generator, shore power & solar panels. Salt & fresh water are manually pumped. Both bilge pump and anchor winch are backed by manual equivalents. Cooking is by 2-burner gas stove. Shower hand-pumps from a bucket of hot water. A composting toilet eliminates through–hull fittings. Engine air cooling ducts run along cabin sides sucking toilet (port) & cabin (starboard) air as they bypass sealable vents. Stale air is expelled into the engine box, along with grey water.

This comfortable “upgraded camping” level makes fine ecological & economic sense, but is not for everyone! A luxury fitout will up displacement, but if weight is kept low the only apparent effect is 55mm/tonne extra immersion at rest.

click to enlarge

A hard chine at WLL provides form stability for the narrow moderate-Vee warped-bottom planing hull. Bottom sections are concave with the deadrise of the planing section dropping over 25ft from 23degrees to just an inch at the stern. The high WL Length:Beam ratio, shallow-Vee & low displacement produce a non-aggressive hull form which slips across & through the water with little fuss or fuel. Such designs are gaining recognition (mainly via the booming Power Cat industry) as a third hull form, unlike the limited speed displacement type or the power-hungry larger deep-Vee planing hull. Wilbur’s “Displaning” or ”Cutwater” hull type increases speed smoothly with power, sans “planing hump”. At low speeds her fine entry slices her along, shifting very little water a very small distance for passage. Stability range, accurately modelled by computer, is 105 degrees with half tankage.

The outboard-in-a-well prevailed over a more economic Inboard diesel to provide easy servicing anywhere. More importantly the mounting plate can be hand cranked in guide slots to clear the prop for beaching & passage transport. This allows headroom despite having to pass a 2.29m2 container door. Positioning forrd beside the outside helm eliminates cavitation. The well’s soundproofed cover is both table & workbench.

The 225HP Honda 4-stroke rockets the narrow hull to 33knots, while the slower 130HP version gives 5nm/gallon. A Yanmar 36HP Diesel outboard returns over 10nmpg @ 8.5 kts. Motor steering is adequate but improvable by low-profile rudders hung from the twin tracking keels. The high-load NZ-designed tender handles rugged conditions and its motor will push the main hull in a breakdown.

Form is dictated by the container’s low cross-sectional area, combined with the need for work-area headroom. Conventional styling looks like a lowered scale model under this constraint, & was rejected in favour of a curvaceous semi-automotive form, with rounded sheer & cabin sections lowering windage. In a seaway Wilbur sheds water easily, but nevertheless the cabin door is watertight.

The E-glass or sheathed cedar strip hull comes in under a tonne. Major bulkheads are foam composite. Interior finish is cream offset with hardwood trim and stained/epoxied ply furniture. Windows are tinted perspex on Sikaflex, Awlgrip decks sheathed end-grain balsa.

Wet areas
The Radar mast (essential for night, fog, traffic & harbour entrance) folds forrd; braced upright it provides a handgrips for the sole foredeck access via ladder. The foredeck is precarious in a seaway, & side-decks virtually non-existent to gain cabin width.

The cockpit is 610mm AWL affording 360deg.visibility. The transom folds down forming a swim platform & opening the RIB garage. Two steps down is the wet (heads & shower) cabin area, & a watertight bulkhead leads to the
Utility/Saloon area
Galley, raised lounge area, inside helm. Ventilation by rear lifting clear hatch over helm. Table and seats may convert to Guest double berth.
Below decks
Chartroom/office/stateroom. Foredeck ladder/hatch , opening ports, 2 Dorade vents. Under-table quarter berth extends beneath helm.

This concept opens overseas coasting to a sector without the time, inclination, or substantial boat for ocean-crossing. It offers a viable worldwide delivery system for builders, and could provide chartering from a Client’s port of choice.

Wilbur is attractive, environment and fuel-responsible, fast, ergonomic, uncluttered and infinitely useable. It can provide a millionaire’s holiday to the far less moneyed.

Click here for Key and illustration