ISO/DIS 3715-1:2026(en)

ISO/TC 8/SC 3

Secretariat: ANSI

Date: 2025-11-26

Ships and marine technology — Propulsion plant for ships — Part 1:

Vocabulary for geometry of screw propellers

Navires et technologie maritime — Installations de propulsion des navires — Partie 1: Termes et

définitions relatifs à la géométrie de l’hélice à vis

© ISO 2026

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Contents Page

Foreword iv

1 Scope 1

2 Normative references 1

3 Terms and definitions 2

4 System of coordinates 11

4.1 System of cartesian coordinates for definition of propeller position at hull 11

4.2 System of cartesian coordinates for definition of propeller geometry 11

4.3 System of cylindrical coordinates for definition of propeller geometry 12

4.4 System of cartesian coordinates for definition of expanded cylindrical blade sections

(see Figure 4 and Figure A.2) 12

Annex A (normative) Hub 13

Foreword

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The committee responsible for this document is ISO/TC 8, Ships and marine technology, Subcommittee SC 3, Piping and machinery.

ISO 3715 consists of the following parts, under the general title Ships and marine technology — Propulsion plant for ships:

— Part 1: Vocabulary for geometry of screw propellers

— Part 2: Vocabulary for controllable-pitch propeller plants

This second edition cancels and replaces the first edition (ISO 3715-1:2002), which has been technically revised.

The main changes compared to the previous edition are as follows:

— title of the document has been changed;

— Figures A.1, A.2, and A.4 have been revised;

— references to figures have been added to the definitions;

— title of Annex A has been changed;

— the document has been revised editorially.

Ships and marine technology — Propulsion plant for ships — Part 1: Vocabulary for geometry of screw propellers

This part of ISO 3715 gives terms and definitions for screw propellers used in the propulsion plants of ships and other vessels (such as mobile offshore drilling units) that are self-propelled or propulsion-assisted. Exceptional designs, as e.g. rim drives, are not covered.

The definitions are valid only for the hydrodynamically effective part of the propeller based on cylindrical blade sections. No definitions are given for the mechanical design of the hub.

Vocabulary for hydraulically operated controllable-pitch propeller plants is given in ISO 3715-2.

There are no normative references in this document.

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1

screw propeller

fluid engine with screw-shaped blades arranged around a rotating axis

3.1.1

propeller radius

R [General]

RP [Computer]

largest distance of the extreme point of a blade (i.e. blade tip (3.3.1)) rectangular to the x-axis

Note 1 to entry: For propellers with adjustable blades and controllable-pitch propellers, this definition is valid for design pitch.

Note 2 to entry: For definition of coordinate system see Figure 2.

3.1.2

propeller diameter

D [General]

DP [Computer]

diameter of the circle passed by the extreme point of a blade (3.3) whilst turning around the x-axis

Note 1 to entry: D = 2R

Note 2 to entry: For propellers with mounted blades and controllable-pitch propellers, this definition is valid for design pitch.

3.1.3

number of blades

Z [General]

Z [Computer]

total number of blades (3.3) of a propeller

3.1.4

disc area

A₀ [General]

A₀ [Computer]

disc area calculated by means of the propeller diameter (3.1.2)

Note 1 to entry: See Figure 2.

3.1.5

area ratio

ratio of any area based on blade geometry and the propeller disc area (3.1.4)

Note 1 to entry: See 3.6.1 for further details.

3.1.6

propeller plane

y- and z-plane

Note 1 to entry: See Figure 2.

3.1.7

direction of rotation, right-handed

<clockwise>

when going ahead the propeller moves in the upper point from left to right (seen from aft)

Note 1 to entry: See Figure A.3.

3.1.8

direction of rotation, left-handed

<counter clockwise>

when going ahead the propeller moves in the upper point from right to left (seen from aft)

Note 1 to entry: See Figure A.4.

3.1.9

angular coordinate

Θ [General]

is coordinate, positive in direction of propeller rotation

Note 1 to entry: See Figure 3.

3.2

hub

boss

part of the propeller the blades (3.3) are fitted to (integral or removable), and forming the connection to the propellers shaft and, in the case of controllable pitch propellers, the housing of the mechanism to pitch the blades (3.3)

Note 1 to entry: The propeller cap is usually not part of the hub (3.2).

3.2.1

hub diameter

d_h [General]

DH [Computer]

diameter of the hub (3.2) in the propeller plane (3.1.6)

Note 1 to entry: See Figure A.1.

3.2.2

fore diameter of hub

d_hf [General]

DHF [Computer]

fore diameter of the hub (3.2), not considering any shoulder

Note 1 to entry: See Figure A.1.

3.2.3

aft diameter of hub

d_ha [General] DHA [Computer]

aft diameter of the hub (3.2), not considering any shoulder

Note 1 to entry: See Figure A.1.

3.2.4

hub length

l_h [General]

LH [Computer]

length of the hub (3.2), any shoulder aft and fore included

Note 1 to entry: See Figure A.1.

3.2.5

aft length of hub

l_ha [General]

LHA [Computer]

length of the hub (3.2) taken from propeller plane (3.1.6) to aft end of the hub (3.2) including aft shoulder

Note 1 to entry: See Figure A.1.

3.2.6

fore length of hub

l_hf [General]

LHF [Computer]

length of the hub (3.2) taken from propeller plane (3.1.6) to fore end of the hub (3.2) including fore shoulder

Note 1 to entry: See Figure A.1.

3.2.7

hub diameter ratio

d_h/D [General]

DHR [Computer]

relation of hub diameter (3.2.1) to propeller diameter (3.1.2)

3.3

blade

part of a propeller beginning at the contour of the hub (3.2) and ending at the blade tip (3.3.1)

3.3.1

blade tip

outermost part of a blade (3.3), positioned at the propeller radius R (3.1.1)

Note 1 to entry: In special cases, the blade tip (3.3.1) is represented by the mid chord point of a cylindrical section at the propeller radius R.

3.3.2

blade root

zone of transition between blade (3.3) and hub (3.2)

3.3.3

leading edge

LE [General and computer]

blade edge directed to the inflow under normal operating conditions starting from the blade root (3.3.2) and ending at the blade tip (3.3.1)

3.3.4

trailing edge

TE [General and computer]

blade edge opposite to the inflow under normal operating conditions starting from the blade root (3.3.2) and ending at the blade tip (3.3.1)

3.3.5

shape of edges

shape of the fore and aft part of a cylindrical section

Note 1 to entry: E.g. rounded, sharpened edges.

Note 2 to entry: Examples of shapes: anti-singing edge, edge with rounded nose (see e.g. 3.4.7.3).

3.3.6

suction side

back

SS [General and Computer]

blade side, directed to the inflow under normal operating conditions

Note 1 to entry: It is the upper side of a cylindrical profile section (see Figure A.2).

3.3.7

pressure side

face

PS [General and Computer]

blade side opposite to the suction side (3.3.6) (see Figure A.2)

3.3.8

blade outline

shape or contour of blade (3.3)

3.3.9

centre of gravity of blade

mass centre of blade (3.3)

3.4

cylindrical blade section

developed penetration area of a cylinder coaxial related to the x-axis of a propeller with a propeller blade at design pitch

Note 1 to entry: See Figure A.2.

3.4.1

chord line of blade section

CLS [General]

the chord line coincides with coordinates x_c

Note 1 to entry: See Figure 5.

3.4.2

mean line of blade section

camber line

MLS [General]

connecting line of the centres of contact circles between suction (3.3.6) and pressure side (3.3.7)

3.4.3

camber

f [General]

F [Computer]

f is equal to maximum y_c-value of the mean line

Note 1 to entry: See Figure A.2.

3.4.4

chord length

c [General]

C [Computer]

developed length of a cylindrical profile section from the leading edge (3.3.3) to the trailing edge (3.3.4)

Note 1 to entry: Maximum x_c see Figure A.2.

3.4.5

leading part of chord length

c_LE [General]

CLE [Computer]

developed length of a cylindrical profile section taken from the leading edge (3.3.3) to the reference line (3.6.4), related to the x_c-coordinate of the cylindrical section

Note 1 to entry: See system of coordinates in Figure A.4 for information.

3.4.6

trailing part of chord length

c_TE [General]

CTE [Computer]

developed length of a cylindrical section taken from the trailing edge (3.3.4) to the reference line (3.6.4), related to the x_c-coordinate of the cylindrical section

Note 1 to entry: See system of coordinates in Figure A.4.

3.4.7

thickness of blade section

Note 1 to entry: See measure t in Figure A.2.

3.4.7.1

maximum thickness of blade section

t [General]

T [Computer]

maximum distance between pressure and suction side (3.3.6) perpendicular to mean line

Note 1 to entry: See system of coordinates; see also Figure A.2 and Figure A.4 for information.

3.4.7.2

local thickness of blade section

t_X [General]

TX [Computer]

blade thickness at any location along the x_c-coordinate axis, measured perpendicular to mean line

Note 1 to entry: See Figure A.2.

Note 2 to entry: Local thickness refers to contact circle diameter see 3.4.2, except for the leading edge region where the leading edge radius (3.4.7.3) determines the contour.

3.4.7.3

leading edge radius

r_LE [General]

RLE [Computer]

radius defining the curvature of the leading edge (3.3.3)

Note 1 to entry: See Figure A.2.

3.5

pitch

P_r [General]

PR [Computer]

covered distance of a point in x-direction after one revolution (Θ = 2π) moving on a screw line at radius r

EXAMPLE For r = 0,7 R, the pitch is P_0,7.

Note 1 to entry: See system of coordinates in Figure 3.

Note 2 to entry: The pitch (3.5) is unambiguously defined only for a helix of a constant lead. The area of a propeller blade is in general not an ideal helicoidal surface, but an area similar to a helicoidal surface. Therefore, only area elements have defined pitch values.

Note 3 to entry: The pitch values of area elements are in general different in both directions, radial and peripheral as well.

3.5.1

pitch angle

ϕ [General]

PHI [Computer]

angle between the helix of constant lead and the propeller plane (3.1.6), taken on the cylindrical surface

Note 1 to entry: See Figure A.3.

3.5.2

pitch of pressure side

P_PS [General]

PPS [Computer]

pitch (3.5) of the line between the first and the last measuring point of the suction side (3.3.6) of a developed cylindrical section

Note 1 to entry: See ISO 484-1.

Note 2 to entry: See Figure A.6.

3.5.3

pitch of chord line

P_CL [General]

PCL [Computer]

pitch (3.5) of the chord between leading edge (3.3.3) and trailing edge (3.3.4) point of the developed chord line

3.5.4

local pitch

P_X [General]

PX [Computer]

pitch (3.5) of the tangent of a curved line

Note 1 to entry: E.g. pressure side (3.3.7) of a cylindrical section, at a certain point.

Note 2 to entry: Approximately, the pitch (3.5) of the line between two adjacent points of a curved line is named local pitch.

Note 3 to entry: These measures will be used for examination purpose of the manufactured propeller in accordance with ISO 484-1.

3.5.5

mean pitch of blade

P_MB [General]

PMB [Computer]

nominal mean pitch (3.5) of the blade (3.3) calculated by means of a defined formula using the pitch (3.5) of n− individual cylindrical sections and the corresponding chord lengths (3.4.4); the defining formula is:

3.5.6

mean pitch of propeller

P_m [General]

PM [Computer]

arithmetical mean, calculated from the mean pitch (3.5) of the individual blades (3.3)

Note 1 to entry: This value is used, for example to calculate the true slip and the apparent slip value as well.

Note 2 to entry: It is used with restrictions for comparison purpose of the propulsion quality of different propellers.

3.5.7

pitch ratio

P_r/D [General]

PRD [Computer]

quotient of a pitch (3.5) at radius r and the propeller diameter (3.1.2)

3.6

description of propeller

Note 1 to entry: See Figure A.4.

3.6.1

blade areas

3.6.1.1

projected blade area

A_P [General]

AP [Computer]

projection of the blade area in the x-direction onto the propeller plane (3.1.6)

Note 1 to entry: See Figure A.4.

3.6.1.2

developed blade area

A_D [General]

AD [Computer]

area enclosed by the connection line between the end points of the cylindrical profile sections turned into the propeller plane (3.1.6) (removal of pitch (3.5) influence)

Note 1 to entry: See Figure A.4.

3.6.1.3

expanded blade area

A_E [General]

AE [Computer]

area enclosed by the connection line between the end points of the developed and additionally straightened sections (removal of pitch (3.5) and radius influences)

Note 1 to entry: See Figure A.4.

3.6.1.4

developed area ratio

A_D/A₀ [General]

DAR [Computer]

developed area of all blades related to the propeller disc area (3.1.4)

3.6.1.5

expanded area ratio

A_E/A₀ [General]

EAR [Computer]

expanded area of all blades related to the propeller disc area (3.1.4)

3.6.1.6

projected area ratio

A_P/A₀ [General]

PAR [Computer]

ratio of all projected blade areas (3.6.1.1) to propeller disc area (3.1.4)

3.6.2

rake and skew of blade sections

Note 1 to entry: see Figure A.3 and also Figure A.4.

3.6.2.1

rake of blade sections

Rk [General]

RK [Computer]

stagger of cylindrical profile sections in direction of the x-axis (positive values opposite to the x-direction)

Note 1 to entry: See Figure A.3.

3.6.2.1.1

rake at tip of blade

Rk_t [General]

RKT [Computer]

distance of the blade tip (3.3.1) from the propeller plane (3.1.6) in x-direction at Θ = 0°

Note 1 to entry: See Figure A.4.

3.6.2.1.2

skew angle of the blade

Θ_S [General]

TETS [Computer]

angle between the tangent to the c/2 line crossing the centre of rotation and the straight line from propeller centre to blade tip (3.3.1) and is to be measured in the projected view in the propeller plane (3.1.6)

Note 1 to entry: See Figure A.4.

3.6.3

clearance curve

C_c [General]

curve describing the overall dimensions of a blade (3.3) passing the x-z-plane

Note 1 to entry: See Figure A.4.

Note 2 to entry: When changing the pitch (3.5), the clearance curve will change too.

3.6.4

reference line

RL [General]

the straight line at x = 0 and Θ = 0°

Note 1 to entry: See Figure A.4.

Key

z_S 0 denominates the ship's waterline.

NOTE Coordinates of the ship given in this figure are marked with subscript s [deviating from the International Towing Tank Conference (ITTC) agreement].

Figure 1 — Cartesian coordinates for definition of propeller position at hull

This system of coordinates is not in agreement with that of the ship in general.

Key

x direction of shaft centreline

y direction to starboard

z direction perpendicular to x- and y-coordinates

RL reference line (see 3.6.4)

1 limit of propeller disc area

0 origin of coordinates

NOTE This system of coordinates is valid independently of the direction of rotation of the propeller.

Figure 2 — Cartesian coordinates for definition of propeller geometry

Key

Θ Angular coordinate of the system of cylindrical coordinates

r Radial coordinate of the system of cylindrical coordinates

  Left-handed propellers are drawn in general as being right-handed.

NOTE This system of coordinates is used, for example, to define the geometry of propeller blades.

Figure 3 — Going ahead with a right-handed propeller seen from behind

Key

Θ Angular coordinate of the system of cylindrical coordinates

r Radial coordinate of the system of cylindrical coordinates

  Left-handed propellers are drawn in general as being right-handed.

NOTE This system of coordinates is used, for example, to define the geometry of propeller blades.

Figure 4 — Going ahead with a left-handed propeller seen from behind

Key

x_c profile defining coordinate

y_c profile defining coordinate

TE trailing edge

LE leading edge

MLS mean line of blade section

CLS chord line of blade section

Figure 5 — Cartesian coordinates for definition of expanded cylindrical blade sections

1. 
   (normative)
   
   Illustration of definitions

a) Examples for hub shapes

b) Hub dimensions

Key

1 convergent

2 drum-shaped

3 divergent

4 propeller plane

5 fore

6 aft

7 cap

^a Direction of the x-coordinate for above examples.

NOTE 1 For hub shapes, see also Figure A.5.

NOTE 2 Shape corresponds to pushing propeller.

Figure A.1 — Hub shapes and dimensions

Key

Figure A.2 — Expanded cylindrical blade section

Key

x Ahead motion

Θ ∙ r Direction of rotation for forward motion (normal operation)

Figure A.3 — Rake and skew of blade sections

Key

Figure A.4 — Description of propeller

Key

1 diameter of hub at fore end

2 diameter of hub at aft end

3 interrupted keyway

4 full-length keyway with keyblock

5 uninterrupted keyway (forward end only)

6 full-lightening chamber

7 lightening chamber with single keyblock

8 lightening chamber with keyblock and block for balancing

9 lightening chamber with part keyblock

10 lightening chamber with part keyblock and part block for balancing

11 recess for rope guard

12 recess for gland ring seal on propeller shaft

13 grease filling holes and vent holes

14 cone fairing spigot

15 oil injection holes

16 spiral oil groove

17 ring oil groove

Figure A.5 — Example types of propeller hubs

Key

1 first measuring point

2 last measuring point

P_PS pitch of pressure side

PS pressure side

SS suction side

Figure A.6 — Pitch of pressure side

Bibliography

ISO 484‑1, Shipbuilding — Ship screw propellers — Manufacturing tolerances — Part 1: Propellers of diameter greater than 2,50 m

ISO 3715‑2, Ships and marine technology — Propulsion plants for ships — Part 2: Vocabulary for controllable-pitch propeller plants