GB2277907A

GB2277907A - Pontoon structures for caravans

Info

Publication number: GB2277907A
Application number: GB9409054A
Authority: GB
Inventors: Barrie Edward Perry
Original assignee: HARTFORD MARINA Ltd
Current assignee: HARTFORD MARINA Ltd
Priority date: 1993-05-11
Filing date: 1994-05-06
Publication date: 1994-11-16
Also published as: GB9309667D0; GB9409054D0

Abstract

A pontoon structure that will support a caravan on water, thus instantly converting the caravan into a houseboat or mobile home, the structure 2 having a plurality of side-by-side spaced pontoons 11 defining between them an elongate recessed area with a floor on which can be positioned a caravan 16, the structure including decking 15 mountable on the pontoons 11 around the in-place caravan 16 at substantially the level of the caravan's floor, to provide a firm footing and ease of access, and to hide the gap under the caravan. The recessed area is defined by a rigid (steel) framework 10 including a pair of channel members 35 for the caravan's wheels, the framework being supported by the pontoon units (11) and advantageously having detachable ramp members 13 for loading purposes. <IMAGE>

Description

Pontoon structures This invention relates to pontoon structures, and concerns in particular such structures as may be used to support a caravan on the water.

Caravans, and especially the large static variety known generally as "mobile homes", are often used to provide residential or holiday accommodation in a suitable location. However, while in many ways quite excellent for providing both short- and long-term housing and shelter, caravans do suffer from a number of apparently trivial yet nevertheless important disadvantages. Thus, the caravan itself, constructed as it is on wheels (and supporting legs), has its internal floor level raised well above the ground, which means not only that its Users must inconveniently step up and down when entering or leaving it but also that with the large gap apparent beneath it the caravan is rather unsightly (and Users commonly seek to hide this gap, and render the view more attractive, by surrounding the base of the caravan with flowers, bushes, and/or a low fence).Again, while a proper mobile, or touring, caravan can temporarily be set down almost anywhere, residential caravans, of the large mobile home variety, need local authority planning permission much like any other permanent building, and while such permission may be granted for large sites near holiday resorts on the coast it is much more difficult to obtain it for an inland site, especially in an area of any significant beauty, as might be typified by the grassland either side of a river, or around the edges of a lake (whether natural or - perhaps made by landscaving a worked-out gravel pit - artificial), and consequerlt]y sucfi sites are both relatively low ill rtilmber aid 1 cjh in price It will therefore be understood that there are a number of minor but significant impediments in the way of utilising mobile-home-type caravans despite their other substantial advantages; for many years ways have been sought to mitigate these, but so far without success.The invention hopes, though, to provide such a way - a way that will not only allow such caravans to be lawfully used to provide pleasant and relatively cheap homes but that will permit the more intensive utilisation of an asset that presently either is being wasted or is at the very least not being used to its full extent, that asset being the abundance of safe, calm, open water provided by both natural and artificial inland lakes (the latter being typified by the landscaped and flooded gravel pits now forming amenities such as inland marinas in association with neighbouring rivers).

The invention enables a conventional and unmodified caravan of any type - but especially one of the mobile home variety - to be used as a houseboat, and its value depends upon the lack of significant planning restrictions relating to houseboats, on the more pleasing visual appearance of a caravan in houseboat form (with that unsightly floor-to-ground gap hidden), and on the increased security inherent in any building located on water as opposed to dry land. Basically, the invention proposes a pontoon structure that will support the caravan (at a suitable height) on water in just the same way as the hull of a ship supports the ship's superstructure, thus instantly converting the caravan from being a house on land to being a house on water - a houseboat.More specifically, the invention suggests a pontoon structure having a plurality of side-by-side spaced pontoons defining between them an elongate recessed area with a floor on which can be positioned a caravan, the structure including decking mountable on the pontoons around the in-place caravan at substantially the level of the caravan's floor, to provide a firm footing and ease of access, and to hide the gap under the caravan.According to the invention, this can best be achieved by making the structure in the form of a rigid (steel) framework having a centrallylocated recessed area in which the caravan may be positioned and supported at a suitable height surrounded by decking (hiding the underneath gap), the floor of this area being in effect little more than a pair of channel members for the caravan's wheels, the framework having peripheral floatation units to support it (by their buoyancy) at an appropriate depth in water, and advantageously having detachable ramp members that can be deployed between the bank and the recessed area and along which the caravan may be rolled to move it between the bank and the pontoon structure.

In one aspect, therefore, the invention provides a pontoon structure on which can be releasably mounted a caravan, the structure having: a plurality of pontoons positioned side by side spaced parallel one to another so as to produce an elongate recessed area therebetween in which can be positioned a caravan; floor means supported by and between the pontoons and defining a base for that recessed area, onto which floor means can be positioned the caravan in place on the structure; and decking mounted on the pontoons around the in-place caravan at substantially the level of the caravan's floor, to provide a firm fr)c)I ilig.

In a more preferred embodiment the invention provides the structure in the form of a rigid framework having a centrally-located recessed area in which the caravan may be positioned and supported at a suitable height surrounded by decking, the floor of this recessed area being defined by a pair of spaced parallel channel members for the caravan's wheels, the framework having peripheral floatation units to support it at an appropriate depth in the water.

The invention provides a pontoon structure on which can be releasably mounted a caravan. In other words, the invention provides a structure, floatable in water, on which may be mounted a caravan so as to make a composite rather like a houseboat. The caravan - which may of course be any sort of caravan, but is preferably that large, generally static sort known as a mobile home, as explained hereinbefore - is releasably mounted on the pontoon structure in any appropriate way such that it can be held firmly in place yet can, if necessary, be unsecured and then removed from the structure. Typically, the structure will incorporate tie means - anchor points and tie straps or chains - by which the caravan may when in position be releasably secured in place.

Although the pontoon structure of the invention could conceivably be two (or more) quite separate and individual pontoon members somehow joined together spaced side-by-side, in fact it is more convenient, and thus preferred, to construct the whole structure as an integral unit in the form of an elongate rigid framework, advantageously made of welded and bolted suitably corrosion-proofed mild steel I-beams, angle-irons and the like, the unit having a centrallylocated recessed area, and then to attach individual floatation units along its sides. These floatation units, which are desirably positioned symmetrically around the structure, and at least at each of the four corners thereof, to make a reasonably stable, rigid ad twist-free combination, may be of any appropriate shape and size, and may take any appropriate form.For example, as to size they should be such - and have such a displacement - that when the pontoon structure is loaded with the caravan (and its contents) it floats with its top/deck about 45cm (1.5ft) above the water surface and has a draught (a depth below the surface) of about 60cm (2ft). So far as shape is concerned the units are conveniently simple cuboids, though they are preferably long, wide and shallow rather than short, narrow and deep, for the former configuration makes them displace much more for only a small increase in submerged depth, and thus assists in keeping the whole structure more stable. With regard to actual material type the units can be hollow metal or plastic/fibreglass tanks, or they can be blocks of a very light material, such as expanded polystyrene or a closed cell polyurethane foam, suitably sealed and protected by a covering of, say, PVC sheeting or (and preferably) a layer of fibreglass-reinforced concrete. Although each pontoon could use a single, giant floatation unit, it is best to employ several small ones, for not only are they cheaper but this provides a measure of insurance - a safety factor - against damage of the unit(s) leading to a loss in buoyancy.

The pontoons of the structure are positioned so as to produce an elongate recessed area therebetween in which can be placed a caravan. Obviously, since different caravans have different sizes and shapes typical sizes are 9.6 by 3.1m (31 by lOft) for a smaller one of the mobile home sort, and 10 by 3.7m (33 by 12ft) for a larger one - it will be necessary to ensure that the size and shape of the between-pontoon area matches that of the intended caravan.

The invention's pontoon structure's recessed area has pontoon-supported floor means defining the area's base, and it is on this floor means that the caravan is placed. The floor means may be a flat sheet (rigidly supported) extending over the whole of the recessed area, like a real floor, but most conveniently it is no more than a pair of parallel channel members suitably sized and spaced apart to accommodate the caravan's wheels, for this keeps down the structure's weight (and material cost). Indeed, because the caravan may actually be delivered to these by temporarily-positioned ramps (see hereinafter), the channel members may be little more than half a metre (a couple of feet) or so long, held in position by bracing cross members.

Once in place the caravan may be supported in the normal fashion, by its wheels and its stabilising legs (these are small strut-like objects at each corner of the caravan that can be wound or jacked down into contact with the ground/floor to brace the caravan in position). Preferably, however, the recessed area is of such a size, and the area's floor is at such a height relative to the surrounding parts of the structure, that the caravan's own underfloor supporting cross members very slightly overhang and are just above those surrounding parts, and the caravan can actually be lowered (using removable chamfered chocks) into place thereon, to provide a very rigid and stable mounting for the caravan.

The recessed area's floor is at such a height relative to the pontoons (or flotation units) and the main parts of the structure that the decking, when in place, is roughly level with the caravan's own floor .(see below).

In order to provide a walkable surface, with a firm footing, around the caravan once in situ on the pontoon structure, appropriate decking - conveniently wooden planking - is mounted on the pontoons around the recessed area, the general dimensions of the structure being such that the decking is at substantially the level of the caravan's floor. As will be appreciated, not only does this decking provide the required walkway at a convenient height relative to the caravan and a sundeck, but it also serves to "hide" the otherwise unsightly gap underneath the caravan.

Once the decking is in place there may be added a stanchion-supported guard- or hand-rail (of wood or a metal such as aluminium) around the edges thereof so as to provide added safety for the Users. Of course, if as might be desired - it is intended to moor a boat alongside the emplaced caravan, then either all or part of the rail can be left off that side or the relevant portion of rail can be made to swing up or back out of the way, like a gate.

To use the pontoon structure of the invention it is first moored end on at the bank (or at some hard or landing stage), and the caravan is then rolled from the bank into position in the recessed area. This is facilitated by having detachable (temporary) ramp members, conveniently channelled, that can be deployed between the bank and the recessed area and along which the caravan may be rolled to move it between the two (each ramp may have fixing means, such as nuts and bolts, or a simple pin and latch arrangement, by which it can be releasably secured at either end, but generally these are not necessary.Obviously, these ramps need to be of a strength and size capable of taking the caravan's weight, and of a length to reach comfortably from the bank to the recessed area (to render easier that task of manoeuvring and installing the ramps, it is possible to make each in two or more shorter sections, each of these being boltable to the next once in position, but this is usually not necessary).

The pontoon structure of the invention can be used to mount a caravan in houseboat style anywhere there is water, but river banks, or marina-style enclaves, seem to be the best sites. It is envisaged, for example, that in a marina environment a set of houseboat caravans would be moored in neat rows along a spine made by a common walkway joining them all, with the usual services - water, electricity and sewage - running along the spine to each mooring, and access to the spine being controlled by some sort of security gateway through which only authorised Users would be able to pass.

An embodiment of the invention is now described, though by way of illustration only, with reference to the accompanying Drawings in which: Figure 1 shows a perspective view from above and one end, partly in see-through, of a caravan-carrying pontoon structure of the invention; Figures 2-4 show respectively side elevation, top plan and end elevation views of the pontoon structure of Figure 1 (the caravan is not shown in Figure 3); and Figure 5 shows a marina layout incorporating a number of houseboat units made by supporting caravans on pontoon structures like that of Figure 1.

Figure 1 shows a caravan (generally 16: this is a conventional mobile-home-type caravan, and is not described further) supported on a pontoon structure (generally 2). The pontoon structure is in the form of a metal framework (generally 10) having five main parts (best seen in Figure 3), namely three parallel spaced cross members (as 3) between the adjacent pairs of which extend two spaced longerons (as 4). Each cross member 3 is a double member, made of two side-by-side spaced parts (as 3a) each of which is shaped to be (seen from the side in elevation) a wide, shallow U-section; the two are held together by channelled cross struts (as 3s), and their shallow U-section defines the recess in which the caravan sits (this is best seen in Figure 4).The ends of the cross members 3 extend laterally, to provide slructural support. for the decking (15) surrounding the caravan, and the channel cross struts 3s in the middle cross member 3 actually form the "floor" of the pontoon structure, on which floor the wheels (as 12) of the caravan stand when it is in place.

The structure's framework 2 is supported on four elongate floatation units (as 11), disposed, in two parallel lines, one at each corner of the framework, and mounted under the framework's cross members' extended ends (by means not shown, but using threaded bolts passing through holes in the cross members' end portions).

To get the caravan into position on the pontoon structure a pair of channel ramps (as 13) is fixed into place (by means not shown) to extend between the bank (6) and the structure's framework 2 (and specifically the middle cross member's cross struts 3s), and the caravan is simply rolled carefully off the bank down the ramps 13 and onto the cross struts 3s. The ramps are then removed, the caravan's support legs (as 14) are jacked down for stahility, and the caravan is tied into p]ace (by means not shown). The decking 15 is then put on the extended ends of the cross members 3 and finally there is erected around (as much as is required of) the decking edge a stanchion-supported handrail (18) - as shown, no rail is along the edge at which the boat (17) has been moored.

Finally, Figure 5 shows a perspective view of a marina including several houseboat-iike caravans mounted on floating pontoon structures of the invention. To either side of a central spine walkway (51) extending from the bank 6 are moored three houseboats (as 52), two on the near side (as viewed) and one on the far side.

Various services (not shown) run along the spine 51 under the walkway te each mooring point, and the landward end of the walkway has a lockable gate (53) thereat to restrict access to the houseboats.

Claims

1. A pontoon structure on which can be releasably mounted a caravan, the structure having a plurality of pontoons positioned side b side spaced parallel one to another so as to produce an elongate recessed area therebetween in which can be positioned a caravan; floor means supported b and between the pontoons and defining a base for that recessed area, onto which floor means can be positioned the caravan in place on the structure; and decking mounted on the pontoons around the in-place caravan at substantially the level of the caravan's floor, to provide a firm footing.

2. A pontoon structure as claimed in Claim 1, which is in the form of a rigid framework having a centrallylocated recessed area in which the caravan may be positioned and supported at a suitable height surrounded by decking, the floor of this recessed area being defined by a pair of spaced parallel channel members for the caravan's wheels, the framework having peripheral floatation units to support it at an appropriate depth in the water.

3. A pontoon structure as claimed in either of the preceding Claims, which incorporates tie means by which the caravan may when in position be releasably secured in place.

4. A pontoon structure as claimed in any of the preceding Claims, wherein the floatation units are positioned symmetrically around the structure, and at least at each of the four corners thereof, to make a reasonably stable, rigid and twist-free combination.

5. A pontoon structure as claimed in any of the preceding Claims, wherein the flotation units are such and have such a displacement - that when the pontoon structure is loaded with the caravan (and its contents) it floats with its top/deck about 45cm (l.Sft) above the water surface and has a draught of about 60cm (2ft).

6. A pontoon structure as claimed in any of the preceding Claims, wherein the flotation units are simple long, wide and shallow cuboids.

7. A pontoon structure as claimed in any of the preceding Claims, wherein the floatation units are blocks of expanded polystyrene sealed within and protected by a covering of fibreglass-reinforced concrete.

8. A pontoon structure as claimed in any of the preceding Claims, wherein each pontoon employs several small flotation units.

9. A pontoon structure as claimed in any of the preceding Claims, wherein the recessed area is of such a size, and the area's floor is at such a height relative to the surrounding parts of the structure, tat the caravan's own underfloor supporting cross members very slightly overhang and are just above those surrounding parts, and the caravan can actually be lowered into place thereon, to provide a very rigid and stable mounting for the caravan.

10. A pontoon structure as claimed in any of the preceding Claims, which also includes detachable ramp members that can be deployed between the bank and the recessed area and along which the caravan may be rolled to move it between the two.

11. A pontoon structure as claimed in any of the preceding Claims and substantially as hereinbefore described.