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Terminology used in this document

Aft point (AP)

Extreme aft point of hull or where the DWL intersects the backbone.


Centre line of vessel.

Base line

A line parallel to DWL drawn through the point of intersection of the midship section and the moulded keel line or the rabbet line as the case may be. It is a horizontal line both in the transverse section and the elevation drawings.


Breadth moulded, width of the boat.


See Shelf.


British Standard


A partition separating the space below the deck into compartments.

Buttock lines

Curves derived from a series of longitudinal sections of the hull of a vessel by vertical planes, parallel to keel and at uniform intervals from it.


The transverse curvature given to the deck of a boat to facilitate drainage and additional strength.


Fore and aft deck beams running along and supporting the half beams.

Cathodic protection

The process of superimposing an electrochemical cell more powerful than the corrosion cell.


The difference of height between the crown of the deck and deck at side measured off the DWL.


Top most point along the longitudinal centre line of the boat deck.


Heavy duty attachment points set into the ground or workshop floor to facilitate the change of direction needed in the use of a winch wire.

Deck at side

Intersection of top of deck to the outside of the hull.

Deck beam

Beam laid across, resting on shelf or clamp each side to support deck planking.

Datum Water Line (DWL)

Is the absolute length of water line in symbols: Drawing Water Line or Datum Water Line.


The process of ensuring that all curves in the lines drawing are true curves without local irregularities or unfairness and that they are in complete agreement in all the three views in the lines drawing viz the profile, body plan and the half breadth plan.


Transverse members fitted to a hull to provide a support for the soles, as well as giving additional transverse strength to the hull.

Forward point (FP)

Extreme forward point of hull or where the DWL intersects the stem.


Transverse members at given spacings throughout the hull.


A network of lines representing the design spacing of stations, water lines and buttock lines.


The broad strakes of wood which strengthen the sheer of the boat on composite vessels.

Half coupling

Means of joining two lengths of shaft and joining shaft to gearbox.

Knuckle line

A line at a given distance from the sheer or deck at side line to create a vertical flat section on the hull.

Length overall (LOA)

The length of a vessel along the centre line from the fore edge of the stem to the aft edge of transom on a horizontal plane including the rail, but excluding overhanging rudder, bow sprit or other appendages.

Limber hole

The angular cut provided on the lowest point of the floor or deck web to allow excess water to flow through.

Liner tube

A tube flanged or unflanged inserted into the ferrocement reinforcement to facilitate removal of equipment fitted to hull or deck.

Lines drawing

The delineation of a vessels form in three planes or views. The profile view, plan view and transverse sections in the body plan.

Load lines (LL)

Lines drawn parallel and above DWL at given spacings.


Laying off the designed lines of a vessel to full size.

Load water line (LWL)

Designated horizontal line for a craft in a given condition of loading.

Mould loft

Large area in a boatyard where the actual lines of the boat are drawn to full scale.


A fabricated shaped unit installed around the propeller to increase its thrust.

Plummer block support

A reinforced pedestal/block provided within the hull to support the shaft plummer blocks.

Power take off (PTO)

Power take off from engine to drive ancillary equipment.


On a ferrocement hull where the outside of the hull skin abutts the side of keel.

Rubbing strake

A section of timber fixed longitudinally on the outside of the hull to act as a fender.


The proportions of the various structural parts of a hull.


The longitudinal line of the side of the hull represented by the deck or gunwale.


Collective name for propeller, stern tube, shafting and couplings.

Water lines

Lines drawn parallel and below DWL at a given spacing.


An extension from the floor in the form of a built in girder in the hull.

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