Rudder stocks


Design:

As every rudder stock is different, we always produce them to the specific customer requirements. In general the designer of the yacht specifies the material and dimensions. We can be of assistance if a calculation for a different material is required or if the design has to be modified for a more economic production. In a lot of cases designers draw a rudder shaft with a maximum diameter rounded off to a full figure (i.e. Ø 70, Ø 80, Ø 90,etc mm). It could be that the calculated diameter is 2 mm less. This is a very costly round off that is completely unnecessary: To achieve a high tolerance surface of Ø 90 mm we would need to use a 100 mm solid bar profile. If the diameter of the rudder stock would be 88 mm, we could use a 90 mm solid bar profile. As the price of bar material goes up exponentially with the diameter, one can save a lot of money by acquiring the exact calculated diameter from the designer.
It is also important to avoid big steps in diameter of the shaft. A good rule to use is: To decrease the shaft diameter with for example 10 mm, one needs 30 mm of height.
One should also avoid having the same diameter of the shaft in the bottom bearing area and the area where the tiller arm or quadrant will be fitted. While mounting the shaft, a roller could get stuck in the keyway and drop in. Just above the bottom bearing, one should trim down the diameter with a couple of mm. This will also simplify the mounting of the rudderstock.
In situations where the two bearings are far apart, some calculation methods come up with a very small top diameter. This should be avoided, as these calculations are based on static loading. As a rudderstock is dynamically loaded (the worst is while motoring), the shaft may start to vibrate.
Attention should also be paid to electrically disconnect the rudder shaft from the rest of the ship. This is independent of the shaft material used. Connection to other materials will lead to a galvanic reaction and potential loss of material of the shaft. Please read our electrolysis section carefully.


Materials:

We can produce your rudder stock in the following five materials. Background information about these materials can be read on our materials page.

    • Aluminium EN 6082 (AlMgSi1)
    • Aluminium EN 7075 (AlZnMgCu1,5)
    • Stainless steel aisi 316 ( 1.4401 )
    • Stainless steel aisi 329 ( 1.4462 or 1.4460)
    • Stainless steel aisi 630 ( 1.4418 )


Spokes:

The spokes on a rudder shaft transmit the steering torque to the rudder blade. A stiff construction is therefore essential for a strong rudder blade. Mostly the spokes are welded to the rudder shaft. Some people think the welding process is weakening the rudder shaft significantly. This is only true when too much heat is driven into the material. This heat could distort the original metal mixture. So it is essential to use MIG welding, a modern welding process that only heats the material very locally without disturbing the original shaft material. Various test done in the past and over 10.000 welded rudder stocks in use all over the world prove that the welding process, if done correctly, the weakening of the shaft can be neglected. It is also important to put the top spoke not too close to the critical point of the shaft. The critical point of a rudder shaft is just below the bottom bearing as the bending torque and side force is the highest on this point.
The spoke design depends on the material of the rudder blade and the way the rudder blade will be made.

Some examples:

Type 1

This spoke arrangement is the most popular. The construction is very simple, cheap to produce, and also extremely stiff. The standard profile of the tang strips is 40 x 10 mm, 60 x 10 mm and 100 x 10 mm in aluminium, 40 x 4 mm and 50 x 5 mm in stainless steel.
This spoke design is ideal when the rudder blade is made in a mould.

Type 2

This spoke arrangement is preferable when the rudder blade is made out of solid wood and, after shaping, covered with glass fiber or epoxy as there will be no air pockets in the blade. The arrangement is also very stiff but more complex to produce and therefore more costly. The standard plate thickness used is 10 mm in aluminium and 5 mm in stainless steel.

Type 3

This spoke arrangement is ideal when the rudder blade is foam filled and made on one-off bases. The rudder profile is adapted in the spoke profile. Normally the thickness of the epoxy layers is subtracted from the rudder profile so all spokes together makes profiling the foam very easy.
This spoke arrangement is also ideal for (hollow) aluminium rudder blades. On this way the shaping of the aluminium plate is much easier. The plate thickness should be subtracted from the rudder profile.
To produce these profiles we would need a 1:1 template, or a CAD drawing.This arrangement is also stiff but complex to produce and therefore more costly. The standard plate thickness used is 10 mm in aluminium and 5 mm in stainless steel.

Type 4

This spoke arrangement is rarely used. Only when a specific classification bureau forbids welding on the shaft this type should be used. The round spokes are pressed into the shaft. Enough bars should be used to allow the rudder torque to be transmitted to the rudder blade. This arrangement is not very stiff as the bars will bend under load.


Emergency tiller connection:

The top of the rudder shaft normally has a connection for the emergency tiller arm. This will be used when the normal steering system fails. We can produce any required connection, but we would prefer some proven solutions.

Some examples:

This emergency tiller connection is the most popular. The construction is very simple,  cheap to produce, and extremely strong. When the top bearing is mounted on the deck the big advantage of this solution over all other solutions is the fact that it doesn’t stick out above deck level. As the inner part of the shaft is used for the emergency tiller arm, the outside surface is still usable for the top bearing. See more on the emergency tiller arm section.

This emergency tiller connection is used when the rudder shaft sticks out above the deck level or ends in a locker. The construction is very simple,  cheap to produce, and extremely strong. Sometimes it is used under deck. This is only possible when the top bearing is not located on deck level, but is situated on a lower level. One would still prefer the solution from type 1, but when the top diameter of the shaft is less than 50 mm type 2 is preferred.


Price table over AlMgSi1 (6082) rudderstocks

Aluminium 6082 is the most popular material, and following table will give a price indication for that material. Rudder stocks in other lengths and materials can be quoted after receipt of the appropriate drawing. Please note that the purpose of this table is to provide a start point to work from. All parameters are changeable and all prices are in € ex. VAT. and ex. transport and subject to change. More info on the special material features of aluminium 6082 can be read on our materials page.

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
50 to 53 mm 1200 mm 2 pcs no no 550
1500 mm 689
54 to 58 mm 1350 mm 2 pcs no no 597
1650 mm 728
59 to 63 mm 1500 mm 2 pcs no no 642
      1800 mm 766
64 to 68 mm 1600 mm 3 pcs yes yes 755
2000 mm 941
69 to 73 mm 1700 mm 3 pcs yes yes 846
2100 mm 1039
74 to 78 mm 1800 mm 3 pcs yes yes 929
2200 mm 1129
79 to 88 mm 1900 mm 3 pcs yes yes 1150
2400 mm 1454
89 to 98 mm 2000 mm 4 pcs yes yes 1630
2600 mm 2056
99 to 108 mm 2100 mm 4 pcs yes yes 2104
2800 mm 2788
109 to 118 mm 2200 mm 4 pcs yes yes 2494
3000 mm 3410
119 to 127 mm 2200 mm 4 pcs yes yes 2831
3000 mm 3871
128 to 137 mm 2200 mm 5 pcs yes yes 3120
3000 mm 4222
138 to 147 mm 2200 mm 5 pcs yes yes 3293
3000 mm 5118
148 to 157mm 2400 mm 5 pcs yes yes 4156
3000 mm 5688

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
50 to 53 mm 1200 mm 2 pcs no no 550
1500 mm 689
54 to 58 mm 1350 mm 2 pcs no no 597
1650 mm 728
59 to 63 mm 1500 mm 2 pcs no no 642
      1800 mm 766
64 to 68 mm 1600 mm 3 pcs yes yes 755
2000 mm 941
69 to 73 mm 1700 mm 3 pcs yes yes 846
2100 mm 1039
74 to 78 mm 1800 mm 3 pcs yes yes 929
2200 mm 1129
79 to 88 mm 1900 mm 3 pcs yes yes 1150
2400 mm 1454
89 to 98 mm 2000 mm 4 pcs yes yes 1630
2600 mm 2056
99 to 108 mm 2100 mm 4 pcs yes yes 2104
2800 mm 2788
109 to 118 mm 2200 mm 4 pcs yes yes 2494
3000 mm 3410
119 to 127 mm 2200 mm 4 pcs yes yes 2831
3000 mm 3871
128 to 137 mm 2200 mm 5 pcs yes yes 3120
3000 mm 4222
138 to 147 mm 2200 mm 5 pcs yes yes 3293
3000 mm 5118
148 to 157mm 2400 mm 5 pcs yes yes 4156
3000 mm 5688

Price table over stainless AISI 630 (1.4542) (17-4PH) rudderstocks

Stainless steel AISI 630 (1.4542) is the most popular stainless steel material for rudderstocks, and following table will give a price indication for that material. Rudder stocks in other lengths and materials can be quoted after receipt of the appropriate drawing. Please note that the purpose of this table is to provide a start point to work from. All parameters are changeable and all prices are in € ex. VAT. and ex. transport and subject to change. More info on the special material features of stainless 630 can be read on our materials page.

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
35 mm 1200 mm 2 pcs no no 408
35 mm 1500 mm 2 pcs no no 502
36 to 39 mm 1500 mm 2 pcs no no 710
40 mm 1300 mm 2 pcs no no 506
40 mm 1600 mm 2 pcs no no 616
41 to 44 mm 1600 mm 2 pcs yes yes 876
45 mm 1300 mm 3 pcs yes yes 676
45 mm 1700 mm 3 pcs yes yes 825
46 to 49 mm 1700 mm 3 pcs yes yes 1075
50 mm 1300 mm 3 pcs yes yes 799
50 mm 1700 mm 3 pcs yes yes 1024
51 to 54 mm 1800 mm 3 pcs yes yes 1369
55 mm 1400 mm 3 pcs yes yes 1020
55 mm 1800 mm 4 pcs yes yes 1305
56 to 59 mm 1900 mm 4 pcs yes yes 1590
60 mm 1500 mm 4 pcs yes yes 1186
60 mm 1900 mm 4 pcs yes yes 1462
61 to 64 mm 1900 mm 4 pcs yes yes 1832
65 to 69 mm 2000 mm 4 pcs yes yes 2121
70 to 74 mm 2200 mm 4 pcs yes yes 2559
75 to 79 mm 2400 mm 4 pcs yes yes 3047
80 to 84 mm 2500 mm 5 pcs yes yes 3375
85 to 89 mm 2500 mm 5 pcs yes yes 3702
90 to 94 mm 2500 mm 5 pcs yes yes 4080
95 to 99 mm 2500 mm 5 pcs yes yes 4437
100 to 104 mm 2800 mm 5 pcs yes yes 5270
105 to 109 mm 2800 mm 5 pcs yes yes 5759

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
35 mm 1200 mm 2 pcs no no 408
35 mm 1500 mm 2 pcs no no 502
36 to 39 mm 1500 mm 2 pcs no no 710
40 mm 1300 mm 2 pcs no no 506
40 mm 1600 mm 2 pcs no no 616
41 to 44 mm 1600 mm 2 pcs yes yes 876
45 mm 1300 mm 3 pcs yes yes 676
45 mm 1700 mm 3 pcs yes yes 825
46 to 49 mm 1700 mm 3 pcs yes yes 1075
50 mm 1300 mm 3 pcs yes yes 799
50 mm 1700 mm 3 pcs yes yes 1024
51 to 54 mm 1800 mm 3 pcs yes yes 1369
55 mm 1400 mm 3 pcs yes yes 1020
55 mm 1800 mm 4 pcs yes yes 1305
56 to 59 mm 1900 mm 4 pcs yes yes 1590
60 mm 1500 mm 4 pcs yes yes 1186
60 mm 1900 mm 4 pcs yes yes 1462
61 to 64 mm 1900 mm 4 pcs yes yes 1832
65 to 69 mm 2000 mm 4 pcs yes yes 2121
70 to 74 mm 2200 mm 4 pcs yes yes 2559
75 to 79 mm 2400 mm 4 pcs yes yes 3047
80 to 84 mm 2500 mm 5 pcs yes yes 3375
85 to 89 mm 2500 mm 5 pcs yes yes 3702
90 to 94 mm 2500 mm 5 pcs yes yes 4080
95 to 99 mm 2500 mm 5 pcs yes yes 4437
100 to 104 mm 2800 mm 5 pcs yes yes 5270
105 to 109 mm 2800 mm 5 pcs yes yes 5759

Price table over stainless AISI 329 (1.4460) rudderstocks

The following table will give a price indication for that material. Rudder stocks in other lengths and materials can be quoted after receipt of the appropriate drawing. Please note that the purpose of this table is to provide a start point to work from. All parameters are changeable and all prices are in € ex. VAT. and ex. transport and subject to change. More info on the special material features of stainless 329 can be read on our materials page.

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
35 mm 1200 mm 2 pcs no no 489
35 mm 1500 mm 2 pcs no no 599
36 to 39 mm 1500 mm 2 pcs no no 791
40 mm 1300 mm 2 pcs no no 638
40 mm 1600 mm 2 pcs no no 765
41 to 44 mm 1600 mm 2 pcs yes yes 1063
45 mm 1300 mm 3 pcs yes yes 854
45 mm 1700 mm 3 pcs yes yes 1033
46 to 49 mm 1700 mm 3 pcs yes yes 1305
50 mm 1300 mm 3 pcs yes yes 1003
50 mm 1700 mm 3 pcs yes yes 1292
51 to 54 mm 1800 mm 3 pcs yes yes 1721
55 mm 1400 mm 3 pcs yes yes 1339
55 mm 1800 mm 4 pcs yes yes 1632
56 to 59 mm 1900 mm 4 pcs yes yes 1917
60 mm 1500 mm 4 pcs yes yes 1522
60 mm 1900 mm 4 pcs yes yes 1857
61 to 64 mm 1900 mm 4 pcs yes yes 2180
65 to 69 mm 2000 mm 4 pcs yes yes 2499
70 to 74 mm 2200 mm 4 pcs yes yes 2933
75 to 79 mm 2400 mm 4 pcs yes yes 3447
80 to 84 mm 2500 mm 5 pcs yes yes 3948
85 to 89 mm 2500 mm 5 pcs yes yes 4378
90 to 94 mm 2500 mm 5 pcs yes yes 4926
95 to 99 mm 2500 mm 5 pcs yes yes 5389
100 to 104 mm 2800 mm 5 pcs yes yes 6456
105 to 109 mm 2800 mm 5 pcs yes yes 7000

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
35 mm 1200 mm 2 pcs no no 489
35 mm 1500 mm 2 pcs no no 599
36 to 39 mm 1500 mm 2 pcs no no 791
40 mm 1300 mm 2 pcs no no 638
40 mm 1600 mm 2 pcs no no 765
41 to 44 mm 1600 mm 2 pcs yes yes 1063
45 mm 1300 mm 3 pcs yes yes 854
45 mm 1700 mm 3 pcs yes yes 1033
46 to 49 mm 1700 mm 3 pcs yes yes 1305
50 mm 1300 mm 3 pcs yes yes 1003
50 mm 1700 mm 3 pcs yes yes 1292
51 to 54 mm 1800 mm 3 pcs yes yes 1721
55 mm 1400 mm 3 pcs yes yes 1339
55 mm 1800 mm 4 pcs yes yes 1632
56 to 59 mm 1900 mm 4 pcs yes yes 1917
60 mm 1500 mm 4 pcs yes yes 1522
60 mm 1900 mm 4 pcs yes yes 1857
61 to 64 mm 1900 mm 4 pcs yes yes 2180
65 to 69 mm 2000 mm 4 pcs yes yes 2499
70 to 74 mm 2200 mm 4 pcs yes yes 2933
75 to 79 mm 2400 mm 4 pcs yes yes 3447
80 to 84 mm 2500 mm 5 pcs yes yes 3948
85 to 89 mm 2500 mm 5 pcs yes yes 4378
90 to 94 mm 2500 mm 5 pcs yes yes 4926
95 to 99 mm 2500 mm 5 pcs yes yes 5389
100 to 104 mm 2800 mm 5 pcs yes yes 6456
105 to 109 mm 2800 mm 5 pcs yes yes 7000

Options:

Options Price in Euro
Keyway (if not standard) or extra keyway. On stocks under diameter 89 mm : 29€ 
On stocks over diameter 89 mm : 103€
Top for emergency tiller (if not standard) type 2 23
Surcharge for top for emergency tiller type 1 On stocks under diameter 89 mm : 35€ 
On stocks over diameter 89 mm : 78€
Surcharge for top for emergency tiller type 3 On stocks under diameter 89 mm : 130€ 
On stocks over diameter 89 mm : 324€
Surcharge for extra spoke type 1 52
Surcharge per spoke type 2 (instead of type 1) 35
Surcharge per spoke type 3 (instead of type 1) 124
Surcharge per spoke type 4 (instead of type 1) 29


Emergency tillers:

Emergency tillers are made of seawater resistant aluminium 6082 (AlMgSI1). They can be produced for rudder shaft top type 1 and 2 . The picture, drawings and table show the standard emergency tillers. Special shapes and type’s can be made on customers request.

EM42050Z

Part No. Description
EM42035Z Emergency tiller for 25mm hole in top of stock (type 1)
EM42050Z Emergency tiller for 35mm hole in top of stock (type 1)
EM42060Z Emergency tiller for 40mm hole in top of stock (type 1)
EM42080Z Emergency tiller for 50mm hole in top of stock (type 1)
EM50500 Emergency tiller for 50mm top of stock (type 2)
EM50600 Emergency tiller for 60mm top of stock (type 2)