Building the Rhine Pusher ' Egrete '

Last updated 17th March 2012

The plans were first published as ' Freebies ' in Model Boats, May 1988 issue. I put them aside with a mental note to think about building a model some time in the future. Last year thoughts returned to building the ' Egrete ' a Rhine pusher, which I believe is one of two similar craft working the river today.

The illustration caught my eye, and my imagination. In need of a change from model engineering projects I decided to build the model ' Egrete ' but in a more permanent material than Plasticard.

 

I contacted the designer Richard Webb, well known for his designs for craft constructed in plastic card and queried with him his thoughts on constructing the model in wood and ply, he thought it feasible as did the Editior of Model Boats Magazine.

So here is the result costructed in wood and ply, happily after all the time employed,

a successful result too !

Length 28" ( 71 cm ) Beam10 " ( 25 cm ) O/A Depth deckhouse lowered 14" ( 35 cm )

Egrete is interesting as it has a deckhouse on a supporting scissors mechanism which permits it to be lowered when passing under many of the bridges encountered in its work.

Working on the water,the prototype embeds the substantial anchors at the stern in the river bed, to secure the boat whilst the barges which it is to tranport are winched back against the push posts on the bow by wiches in the winch house at the bow. This is essential to ensure that the barges are securely attached and that that the load can be navigated safely in the congested river, especially when passing under the bridges, which in itself is a feat of navigation, particularly where the bridges are on a curve as in Basel !

The published plans ( Still available from Nexus ) are for a model constructed using styrene sheet but, although I have great regard for the work of  Richard Webb in this medium, the engineer in me demands something more substantial. I decided on timber and ply construction throughout.

Having found an ( almost ) perfectly flat building board, flat enough for the purpose that is......... how could it be perfectly flat ? And having purchased a mint set of drawings, battle commenced.

The sections on the drawing were developed with the vertical members of the frames extended to a common level to allow inverted construction of the hull.

The timber frames and strakes were constructed using timber recovered from the carcass of redundant kitchen cabinets. The material used when they were originally installed was knot free high quality pine and could be ripped to size on the band saw and subsequently planed to size. The joy being that the material cost nothing, except my labour, that is ! The ply was marine quality 1.5mm ply from the local model shop.

With the frames erected and true, with housings for the strakes cut, the strakes were installed using brass pins and  PVA adhesive, bought by the 4.5 liter container. It is always useful around the house and comes in at about 1/3 the price or less than the small bottles in which it is otherwise sold. In passing I would add that it is far more economic to buy hot glue sticks if needed by weight at a building supply store than in the bubble pack at DIY shops.

The hull is of rectangular section throughout with only a small amount of strake bending required at the bow, almost like building an inverted box !

As soon as frames and strakes were completed hardwood blocks were installed as the bases for the motor mounts, also ply gussets in the sloping section where the propeller shafts were to pass through the hull. 

The hull bottom sheeting was commenced, and the motors and propeller shafts installed. Bottom sheeting was completed by persuading the ply around the gentle upsweep at the bow. it is sometimes useful to wet the outer veneer ( only ) where acute curves or changes of plane are to be achieved.

Substantial rails were inserted to allow firm fixings for the push posts to be added later. This has since proved to be a wise move as these posts take impact loading when coupling to a load, and when the boat is handled with too much gusto by younger members of the family ! 

At this stage the hull was severed from the building board, always an exciting moment.. With only the bottom sheeting installed the structure proved to be extremely rigid, such that all further sheeting and installation could be carried out without any distortion of the hull.  and with the hull in the position best suited to the work.

Vertical alignment of the motors and shafts was simple as it was possible to sight the alignment through the unsheeted sides of the hull.

Of course the deck beams already existed as part of the frames and it was only necessary to remove the parts that interfered with superstructure location and access and to trim these openings with more of the  ' Kitchen cabinet material ' 

Side sheathing and decking were again simple operations due to the box section of the hull.

The overall design of the vessel permits the superstructure to be constructed integral with the hull and deck, avoiding problems with water ingress in ' Heavy weather '  Decking throughout the hull and superstructure is flat, again simple to install, first though the push posts, sawn from hardwood, must be securely screwed in place from within the hull. 

Superstructure front and sides were reinforced with strip wood, placed to provide support for the upper decks. Miscellaneous fixings and fixtures were added from ply and styrene sheet to complete the overall appearance. Painting included shellac sealer, primer, undercoat and two coats of Dulux ! 

The bridge deck, on ' Scissor ' supports to allow it to be lowered to pass beneath bridge arches, is an important feature of the craft and the complicated form calls for a lot of fretwork to achieve the many openings and complicated form.

A model of the bridge deck was first constructed in card then the panel outlines transferred to 1.5mm ply.

PVA adhesive was used in construction and an assortment of wooden blocks for support  whilst the PVA hardened .This ensured a rigid and accurate bridge deck. Glazing was from 1/16" Perspex fixed using contact adhesive.

The scissors hoisting arms were cut from aluminum sheet and combined with 1/8" diameter rod, threaded 8BA as required to provide the up and down motion( yet to be motorized). Considerable care was required to get the whole mechanism working freely and without twist.

The cable guides on the foredeck were built from brass rod and sheet brass. Cyano was used to bond these materials, The decision taken at this stage to provide the the cable ports with covers ( unlike those on the prototype ) has proved to be a wise step in view of the water that washes up the square bows at speed.

 Stacks are from ply. The companionway which accommodates the rise and fall of the bridge deck from brass strip and rod, and the railings from brass rod too.

Bollards are from styrene, as is the dory complete with the outboard motor. The crane and fold down mast are from brass tube, the parts  again soldered. The styrene sheet used for the dory was recovered from the bottom of an ice cream carton, the source of material for many of the buildings on my model railway…… economy again !

 Brass sheet was bent around a coke bottle used as a former and soldered up to make steerable 'Kort ' type nozzles around the fixed propellers. These are similar to those for Egrete although actually for the current project, the workboat

The steering servo is mounted under a hatch which supports the hawser baskets, also the anchor winches and chain troughs. The shafts of the anchors are within tube supported from the hull by bolted brackets.

The anchors are again soldered from tube and plate,  In practice they are extremely important as they are used to anchor the vessel against the effort applied by the winches in the winch house at the bow.

Having lost an anchor in a collision on the water the model now has a protective rail around the anchors just above water level.

The pusher was completed by the addition of restraints for the 6V 12Ah  Battery, the Msonics digital speed controller and the Action multiswitch ( installed with future working features in mind )

Here is a carrier/launcher which is built of copper pipe, plumbing fittings and scrap ply.

The assembly serves also as a storage shelf ( 'anging on 'ooks ) in the congested workshop

 

On the water the model is great to operate, steering is precise and immediate, the two 480 motors providing more than adequate power and  speed. 

Two of my models on the local water. Here Egrete is accompanied by a launch (which i built to a different scale ! ) nearly 50 years ago, when just a lad in fact !

The unusual nature of the boat causes a lot of interest although many people are puzzled by the shape and think that it is some sort of ferry !

This boat is straightforward to build, has interesting details and would make an ideal project for a modeller branching into scratchbuilding, especially if the budget for the build is ' Tight '

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