Tie-down lashing.

In this friction-based lashing method, the load to be secured is spanned by lashing straps, pressed down onto the loading area and thus secured on all sides.
To prevent the load from slipping, the contact force between the load and the loading area – and thus the frictional force – is increased by means of pre-tensioning forces. The preload (S_TF) should be of equal magnitude across all spans. It is important that the load is generally suitable for the lashing method.

For security reasons, after VDI 2700 Part 2 (July 2014), lashing equipment must not be pre-tensioned to more than 50 per cent of the maximum lashing force (LC). Otherwise, dynamic forces occurring whilst driving may overload the straps . The pre-tension should be checked regularly whilst driving (particularly shortly after setting off).
To ensure pre-tension when lashing down on both sides of the load, we recommend edge protection sliders, which ensure a more even distribution of force across the lashing equipment and also provide protection for the textile webbing at the edges of the load.

Table of contents.

Calculation formula for a free-standing, stable load unit

Definitions of abbreviations

Example calculation for lashing down

Our Dolezych-Einfach-Methode^© – Tie-down lashing

Load securing products

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Calculation formula for a free-standing, stable loading unit:

F_iS = m · g · (f_l,q − μ · f_v) k · n · μ · sin α

Massenkräfte beim Niederzurren Darstellung

Resources

Dolezych’s Simple Method^©
Trucker’s Disc

The acceleration values shown in the table relate to a vehicle with a maximum authorised mass exceeding 3.5 tonnes.

Abbreviations	Definition	Explanation according to VDI 2700
a	Acceleration of the charge	Maximum acceleration of the load due to the course of the journey
f	Acceleration coefficient	Coefficient for determining the magnitude and direction of the mass force of the charge
f_lv	Forward longitudinal acceleration coefficient	= 0.8 during braking manoeuvres
f_lh	Longitudinal acceleration coefficient for reversing	= 0.5 during acceleration
f_q	Lateral acceleration coefficient	= 0.5 when cornering
f_v	Vertical acceleration coefficient downwards	= 1.0
F_G	Weight force	Force exerted by the load on a horizontal loading surface
F_iS	Pre-tension force in the lashing	Resistance force that must be applied in addition to the sliding friction force, e.g. by lashing equipment, to secure a load against inertial forces
g	acceleration due to gravity	g = 9.81 m/s²
k	Coefficient	Coefficient that takes into account the loss of pre-tensioning force due to friction between the lashing and the load
n	Number of lashing devices/lashing points
m	Mass of the load	Mass to be secured
α	Vertical angle	Angle between the lashing and the loading area of a means of transport
μ	Coefficient of friction	Coefficient used to determine the friction between the load and the respective surface whilst the load is moving relative to the loading area

The calculation for tie-down lashing.

For safety reasons, when calculating the load-securing force, the result must always be rounded up to ensure that a sufficient number of lashing straps are used.
Units must always be converted to SI units. For example, the weight of the load in kg and the tension in the strap in newtons (N).
A transfer coefficient lower than k = 1.8 may occur if lashing equipment is routed over particularly rough surfaces, for example. In such cases, please take appropriate measures to ensure the force is distributed evenly throughout the lashing system (e.g. by using edge sliders).

Our Dolezych Simple Method^© – Securing loads

A simple method for quickly selecting the necessary lashing straps for securing loads. To do this, the table on the following page calculates the number of lashing straps required based on the following criteria:
- Pre-tension force (S_TF)
- Coefficients of friction (0.1 | 0.3 | 0.6)
- Lashing angle α (35°, 60° or 90°)
- Load weight (up to 16 t)
When selecting the lashing angle, always choose the next lower angle from the table. Vertical angles below 35° are uneconomical and are therefore not taken into account.

Calculation example in accordance with VDI 2700 Sheet 2 (July 2014)

n = m · g · (f − μ) k · F_iS · μ · sinα

Load weight	m = 6,000 kg
Coefficient of friction	μ = 0.3
Lashing angle	α = 60°
Transfer coefficient	k = 1.8
Gravitational acceleration	g = 9.81 m/s²
Acceleration coefficient	f = 0.8
Acceleration coefficient	f = 0.8
Preload force value	F_iS

Example for F_iS = 680 daN = 6,800 N

n = 6,000 · 9.81 · (0.8 − 0.3) 1.8 · 6,800 · 0.3 · sin 60° = 9.25

Result: In this example, therefore, 10 lashing straps (rounded up) with a S_TF of 6,800 N or 680 daN must be used.

Product	STF	Number of lashing straps
DoZurr5000 with standard ratchet	300 daN	21
ThuTension with standard ratchet	420 daN	15
DoZurr5000 with DoMulti500	500 daN	13
DoZurr5000 with DoMulti600	600 daN	11
DoZurr4000 with DoMulti	680 daN	10
DoTension with DoMulti	720 daN	9
PowerLash power-assisted with gear ratchet (75 mm)	1,000 daN	7

The Dolezych Simple Method^© was developed to determine the selection of the required lashing equipment even more quickly. The calculation is based on VDI 2700 Part 2 (July 2014) and includes a safety factor.

The following generally applies to the calculation:

Free-standing, homogeneous, stable load
The pre-tension force S_TF on the side opposite the lashing device corresponds to at least 50 per cent (k = 1.8).
Table values are rounded up to the nearest whole number.
Table values greater than 35 are not shown due to lack of cost-effectiveness.

Payload weight (m) ⟶			1 t			2 t			3 t			4 t
Angle α ⟶			35°	60°	90°	35°	60°	90°	35°	60°	90°	35°	60°	90°
Preload force S_TF ↓		μ ↓	Number of lashing straps required
DoZurr5000 DoRapid5000 DoPremium5000	300 daN	0,1	23	15	13		30	26
		0,3	6	4	4	11	7	7	16	11	10	22	14	13
		0,6	2	2	2	3	2	2	4	3	2	5	3	3
DoZurr4000	320 daN	0,1	21	14	12		28	24
		0,3	5	4	3	10	7	6	15	10	9	20	14	12
		0,6	2	2	2	2	2	2	3	2	2	4	3	3
DoTension420	420 daN	0,1	16	11	10		21	19			28
		0,3	4	3	3	8	5	5	12	8	7	16	10	9
		0,6	2	2	2	2	2	2	3	2	2	4	2	2
DoZurr5000 mit DoMulti500 oder Do2Step	500 daN	0,1	14	9	8	27	18	16		27	23
		0,3	4	3	2	7	5	4	10	7	6	13	9	8
		0,6	2	2	2	2	2	2	2	2	2	3	2	2
DoZurr5000 oder DoPremium5000 jeweils mit DoMulti600	600 daN	0,1	12	8	7	23	15	13		23	20		30	26
		0,3	3	2	2	6	4	4	8	6	5	11	7	7
		0,6	2	2	2	2	2	2	2	2	2	3	2	2
DoZurr4000 mit DoMulti	680 daN	0,1	10	7	6	20	13	12	30	20	17		26	23
		0,3	3	2	2	5	4	3	7	5	5	10	7	6
		0,6	2	2	2	2	2	2	2	2	2	2	2	2

Payload weight (m) ⟶			6 t			10 t			12 t			16 t
Angle α ⟶			35°	60°	90°	35°	60°	90°	35°	60°	90°	35°	60°	90°
Preload force S_TF ↓		μ ↓	Number of lashing straps required
DoZurr5000 & DoRapid5000 & DoPremium5000	300 daN	0,1
		0,3		21	19
		0,6	7	5	4	11	7	7	13	9	8	17	12	10
DoZurr4000	320 daN	0,1
		0,3	30	20	18			29
		0,6	6	4	4	10	7	6	12	8	7	16	11	10
DoTension420	420 daN	0,1
		0,3	23	15	13		25	22		30	26
		0,6	5	3	3	8	5	5	10	6	6	13	8	7
DoZurr5000 mit DoMulti500 oder Do2Step	500 daN	0,1
		0,3	20	13	11		21	19		26	22			30
		0,6	4	3	2	7	5	4	8	6	5	11	7	6
DoZurr5000 oder DoPremium5000 jeweils mit DoMulti600	600 daN	0,1
		0,3	16	11	10	27	18	16		21	19		28	25
		0,6	4	3	2	6	4	4	7	5	4	9	6	5
DoZurr4000 mit DoMulti	680 daN	0,1
		0,3	14	10	9	24	16	14	28	19	17		25	22
		0,6	3	2	2	5	4	3	6	4	4	8	5	5