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The original design of the horse drawn ice boat proved to be very successful and in some cases boats of this original design were still in occasional use almost until the end of the canal's commercial life, although in the later years powered vessels did undertake most of the work.
In design and construction these horse drawn ice boats were the purest form of working boat, designed and constructed solely for their specific task, with no frills, refinements or decoration whatsoever. Although similar, each canal system had its own particular design of ice boat which, it would seem from the initial examination of the remaining L&L boats, had further detail variations most likely attributable to the particular yard where a boat was constructed.
Interestingly the remains still provide many examples of the technology associated with their construction such as the wrought iron nails, brackets and bolts and even, on one of the remaining boats, the chisel marks remaining from when a large securing bolt was roughly tighten at some time.
The following details of construction have been derived from examination
of the three remaining boats:
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By ice boat standards L&L boats were large in keeping with the dimensions of the wide canal. Based on the examination of the remaining three boats it would seem there was some variation in the dimensions of the individual boats around a length of 13.72 metres (45 feet) and breadth of 2.13 metres (7 feet).
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A key feature of the ice boat design was a distinct "V" cross-section of the hull to maximise the rocking effect of the boat when in operation.
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The forward section of the keel has a distinct "raked" line which would assist the "riding" up of the boat onto the ice when in operation. This was further accentuated by additional ballast to the rear of the boat to the extent that when the boat was trimmed for operation its forward section could be completely clear of the water.
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As the bow was raised clear of the water when working it was presumably unnecessary to have any conventional streamlining. The squared construction would also facilitate the strengthening of the boat.
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An unusual feature of these boats and relatively unique in wooden boat construction generally which, it is presumed, minimised the possible damage to plank edges when in operation.
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The planks are butted up against each other with a sealing material or caulking driven into the seams to make the hull watertight. |
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With an operation that was based upon the application of brute force it is expected that the structure would be appropriate for the job and these features of the construction are worthy of specific reference:
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Greenheart Keel.
Greenheart is a heavy tropical hardwood timber of a particularly durable nature and was stated as being the particular timber used for the heavy keel of these boats.
At this time the use of this particular timber has not been verified on any of the remaining boats.
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Keelson.
A longitudinal internal timber fastened down to the keel which provides rigidity and stiffness to the boat. In the ice boat this is also an extremely heavy timber for the size of vessel measuring some 425mm (15in) square.
A further important function of the keelson where a boat has vertical planking is to secure the ends of the planks.
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Stringers.
These elements of the boat's construction run along the length of the boat, again to provide rigidity and stiffness to the boat as a whole. In the L&L boats they are again extremely large timbers for the size of boat and also provide a mid point fixing to the vertical planking.
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Thickness of Planking.
In order to withstand the abrasive forces when operating the planking is correspondingly extremely heavy, having a thickness in the region of 40 mm.
The actual timber used for the planking has not been established at this time.
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Heavy Bracketing and Strengthening.
The whole structure incorporates major support brackets, bolts and fixings at the key stress points throughout the vessel.
A number of these have been identified as part of theses initial investigation but extent of these supports and how the total structure is strengthening remains to be analysed fully.
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The gunwale is the
top edge
of the boat's side and in the
case of the L&L Ice Boats it
is constructed from very heavy
timbers.
The most common alignment for the planking of a wooden boat is along the length of the boat in which case the fixing would be to a series of ribs. However in the icebreakers, as the planking is vertical, ribs cannot provide the structural support and are completely absent.
The Keelson, Stringers and Gunwale* provide the necessary fixing and support for the planking.
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The boats usually had three short masts, one as a towing mast, to which a towing rope would be attached, and the other two supporting either end of a bar or tie for the rocking team to hold when operating the boat.
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Although not clearly illustrated, these boats had a line that could be described as being "canoe" like and is quite unlike the wide bodied cargo boats that were usually associated with the canal. Interestingly this feature originally provided an important clue to the first vessel's identification and subsequently it was found that all the remains give some indication of this distinctive line in what would normally be envisaged as a rough and clumsy boat
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As referred to earlier large teams of horses could be used when operating the ice boats and, as well as the towing mast, boats had a number of additional points to which tow ropes could be attached. Some specific examples identified include large swivel hooks on the gunwales and lug upon the metal cover plate to the keel/keelson at the bow.
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