Any boat that is 34m long and 13.7m wide is not going to be easily and affordably slipped, where slipping cradles for such dimensions would be intended for much heavier boats, and or, where travel lifts would battle with the 13.7m beam.
With a stated objective of day to day running cost economy, it would arguably be wasteful, if for example, all the monies saved on fuel over a year, were lost in having to use unnecessarily expensive and heavy slipping services.
With the longer term objective of the Trybrid to provide a fast affordable ‘aid work platform’ for third world use, there seems logic in aiming to design the boat so it is easily serviced and repaired, in areas, for example, of primitive infrastructure. It would not be helpful, if for example, a propeller or skin fitting needed urgent repair when the vessel was engaged in emergency work, a thousand miles from a capable slipway.
Without a deep keel, and with a mere 1.2m draft, it will be possible to wade out around the boat without swimming.
With a hull width, up say 500mm from the keel, the central hull’s beam width is not much more than a man’s arm span, so there is some freedom from the usual constraints that would normally deter the idea of in-building cradle wheel guides. The boat is designed to embody inbuilt under hull guides for axle and wheel cradles.To deploy the cradle, a wheel set is cast overboard, attached, up through under hull hause guides, and winched into a locked position. The axle and wheel cradles will be winched up into internal, 250-380mm alloy guides, which will be designed to bear the boat’s 50t weight across several wheel sets, applying roughly the same dead load at the location that a travel lift sling would adopt.
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There is no wheel drive system needed to haul the vessel up the beach. The boat uses the anchor winch as the slow crawl method of progress. The boat has both a fore and aft winch, capable of slowly drawing the boat up a ramp or beach, and back down the beach through a pre-laid stern anchor for the return trip.
If the Trybrid has say a 50-90 year usable life, and is being designed for a suggested climate changed world, is it not inappropriate to hypothesize that future-ready vessels would be advantaged, if they have shallow water, or semi-amphibious capability?
The ability to crawl ashore, where conditions are calm, or on boat ramp allows the boat onshore after a major natural disaster. Once ashore, the ability of such a vessel to render assistance with its desalination and power generation capability is unusual. The solar array fold out, pop-top cabins, with internal hose out design, helps the vessel’s to act well in a first aid role.
Whilst not yet subject to detail engineering design, there has been considerable interest in deploying wheels ex of small and redundant jet aircraft, where many high strength, and appropraitely sized wheel sets sit unused in US plane wrecker yards.