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 page.

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
40 to 49 mm 1100 2 pcs no no 560
1400 628
50 to 54 mm 1200 2 pcs no no 660
1500 744
55 to 59 mm 1300 2 pcs no no 752
1700 888
60 to 64 mm 1500 3 pcs yes yes 1020
1800 1148
65 to 69 mm 1600 3 pcs yes yes 1116
2000 1312
70 to 74 mm 1700 3 pcs yes yes 1272
2100 1460
75 to 79 mm 1800 3 pcs yes yes 1396
2200 1676
80 to 89 mm 1900 4 pcs yes yes 1852
2400 2224
90 to 99 mm 2000 4 pcs yes yes 2260
2600 2756
100 to 109 mm 2100 4 pcs yes yes 2672
2800 3312
110 to 119 mm 2200 4 pcs yes yes 3112
3000 3956
120 to 129 mm 2200 5 pcs yes yes 3624
3000 4576
130 to 139 mm 2200 5 pcs yes yes 4044
3000 5144
140 to 149 mm 2200 5 pcs yes yes 4492
3000 5752
150 to 159 mm 2400 5 pcs yes yes 5312
3000 6392
160 to 164 mm 2400 5 pcs yes yes 5676
3000 6820

Shaft diameter Shaft length Number of typ 1 spokes Keyway Top for emergency tiller type 1 Price in Euro
40 to 49 mm 1100 2 pcs no no 560
1400 628
50 to 54 mm 1200 2 pcs no no 660
1500 744
55 to 59 mm 1300 2 pcs no no 752
1700 888
60 to 64 mm 1500 3 pcs yes yes 1020
1800 1148
65 to 69 mm 1600 3 pcs yes yes 1116
2000 1312
70 to 74 mm 1700 3 pcs yes yes 1272
2100 1460
75 to 79 mm 1800 3 pcs yes yes 1396
2200 1676
80 to 89 mm 1900 4 pcs yes yes 1852
2400 2224
90 to 99 mm 2000 4 pcs yes yes 2260
2600 2756
100 to 109 mm 2100 4 pcs yes yes 2672
2800 3312
110 to 119 mm 2200 4 pcs yes yes 3112
3000 3956
120 to 129 mm 2200 5 pcs yes yes 3624
3000 4576
130 to 139 mm 2200 5 pcs yes yes 4044
3000 5144
140 to 149 mm 2200 5 pcs yes yes 4492
3000 5752
150 to 159 mm 2400 5 pcs yes yes 5312
3000 6392
160 to 164 mm 2400 5 pcs yes yes 5676
3000 6820

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 570
35 mm 1500 mm 2 pcs no no 706
36 to 39 mm 1500 mm 2 pcs no no 973
40 mm 1300 mm 2 pcs no no 735
40 mm 1600 mm 2 pcs no no 897
41 to 44 mm 1600 mm 2 pcs yes yes 1233
45 mm 1300 mm 3 pcs yes yes 961
45 mm 1700 mm 3 pcs yes yes 1199
46 to 49 mm 1700 mm 3 pcs yes yes 1539
50 mm 1300 mm 3 pcs yes yes 1156
50 mm 1700 mm 3 pcs yes yes 1488
51 to 54 mm 1800 mm 3 pcs yes yes 1968
55 mm 1400 mm 3 pcs yes yes 1483
55 mm 1800 mm 4 pcs yes yes 1866
56 to 59 mm 1900 mm 4 pcs yes yes 2338
60 mm 1500 mm 4 pcs yes yes 1777
60 mm 1900 mm 4 pcs yes yes 2210
61 to 64 mm 1900 mm 4 pcs yes yes 2712
65 to 69 mm 2000 mm 4 pcs yes yes 3196
70 to 74 mm 2200 mm 4 pcs yes yes 3919
75 to 79 mm 2400 mm 4 pcs yes yes 4730
80 to 84 mm 2500 mm 5 pcs yes yes 5355
85 to 89 mm 2500 mm 5 pcs yes yes 5920
90 to 94 mm 2500 mm 5 pcs yes yes 6554
95 to 99 mm 2500 mm 5 pcs yes yes 7178
100 to 104 mm 2800 mm 5 pcs yes yes 8657
105 to 109 mm 2800 mm 5 pcs yes yes 9478
110 to 114 mm 2800 mm 5 pcs yes yes 10328
115 to 119 mm 2800 mm 5 pcs yes yes 11314
120 to 124 mm 2800 mm 5 pcs yes yes 12359
125 to 129 mm 2800 mm 5 pcs yes yes 13439

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 570
35 mm 1500 mm 2 pcs no no 706
36 to 39 mm 1500 mm 2 pcs no no 973
40 mm 1300 mm 2 pcs no no 735
40 mm 1600 mm 2 pcs no no 897
41 to 44 mm 1600 mm 2 pcs yes yes 1233
45 mm 1300 mm 3 pcs yes yes 961
45 mm 1700 mm 3 pcs yes yes 1199
46 to 49 mm 1700 mm 3 pcs yes yes 1539
50 mm 1300 mm 3 pcs yes yes 1156
50 mm 1700 mm 3 pcs yes yes 1488
51 to 54 mm 1800 mm 3 pcs yes yes 1968
55 mm 1400 mm 3 pcs yes yes 1483
55 mm 1800 mm 4 pcs yes yes 1866
56 to 59 mm 1900 mm 4 pcs yes yes 2338
60 mm 1500 mm 4 pcs yes yes 1777
60 mm 1900 mm 4 pcs yes yes 2210
61 to 64 mm 1900 mm 4 pcs yes yes 2712
65 to 69 mm 2000 mm 4 pcs yes yes 3196
70 to 74 mm 2200 mm 4 pcs yes yes 3919
75 to 79 mm 2400 mm 4 pcs yes yes 4730
80 to 84 mm 2500 mm 5 pcs yes yes 5355
85 to 89 mm 2500 mm 5 pcs yes yes 5920
90 to 94 mm 2500 mm 5 pcs yes yes 6554
95 to 99 mm 2500 mm 5 pcs yes yes 7178
100 to 104 mm 2800 mm 5 pcs yes yes 8657
105 to 109 mm 2800 mm 5 pcs yes yes 9478
110 to 114 mm 2800 mm 5 pcs yes yes 10328
115 to 119 mm 2800 mm 5 pcs yes yes 11314
120 to 124 mm 2800 mm 5 pcs yes yes 12359
125 to 129 mm 2800 mm 5 pcs yes yes 13439

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 646
35 mm 1500 mm 2 pcs no no 795
36 to 39 mm 1500 mm 2 pcs no no 1097
40 to 44 mm 1600 mm 2 pcs yes yes 1475
45 to 49 mm 1700 mm 3 pcs yes yes 1845
50 to 54 mm 1800 mm 3 pcs yes yes 2418
55 to 59 mm 1900 mm 4 pcs yes yes 2788
60 to 64 mm 1900 mm 4 pcs yes yes 3200
65 to 69 mm 2000 mm 4 pcs yes yes 3749
70 to 74 mm 2200 mm 4 pcs yes yes 4509
75 to 79 mm 2400 mm 4 pcs yes yes 5406
80 to 84 mm 2500 mm 5 pcs yes yes 6248
85 to 89 mm 2500 mm 5 pcs yes yes 6957
90 to 94 mm 2500 mm 5 pcs yes yes 7799
95 to 99 mm 2500 mm 5 pcs yes yes 8577
100 to 104 mm 2800 mm 5 pcs yes yes 10391
105 to 109 mm 2800 mm 5 pcs yes yes 11318
110 to 114 mm 2800 mm 5 pcs yes yes 12283
115 to 119 mm 2800 mm 5 pcs yes yes 13511
120 to 124 mm 2800 mm 5 pcs yes yes 14935
125 to 129 mm 2800 mm 5 pcs yes yes 16137

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 646
35 mm 1500 mm 2 pcs no no 795
36 to 39 mm 1500 mm 2 pcs no no 1097
40 mm 1300 mm 2 pcs no no 859
40 mm 1600 mm 2 pcs no no 1037
41 to 44 mm 1600 mm 2 pcs yes yes 1475
45 mm 1300 mm 3 pcs yes yes 1135
45 mm 1700 mm 3 pcs yes yes 1398
46 to 49 mm 1700 mm 3 pcs yes yes 1845
50 mm 1300 mm 3 pcs yes yes 1347
50 mm 1700 mm 3 pcs yes yes 1743
51 to 54 mm 1800 mm 3 pcs yes yes 2418
55 mm 1400 mm 3 pcs yes yes 1789
55 mm 1800 mm 4 pcs yes yes 2210
56 to 59 mm 1900 mm 4 pcs yes yes 2788
60 mm 1500 mm 4 pcs yes yes 2095
60 mm 1900 mm 4 pcs yes yes 2580
61 to 64 mm 1900 mm 4 pcs yes yes 3200
65 to 69 mm 2000 mm 4 pcs yes yes 3749
70 to 74 mm 2200 mm 4 pcs yes yes 4509
75 to 79 mm 2400 mm 4 pcs yes yes 5406
80 to 84 mm 2500 mm 5 pcs yes yes 6248
85 to 89 mm 2500 mm 5 pcs yes yes 6957
90 to 94 mm 2500 mm 5 pcs yes yes 7799
95 to 99 mm 2500 mm 5 pcs yes yes 8577
100 to 104 mm 2800 mm 5 pcs yes yes 10391
105 to 109 mm 2800 mm 5 pcs yes yes 11318
110 to 114 mm 2800 mm 5 pcs yes yes 12283
115 to 119 mm 2800 mm 5 pcs yes yes 13511
120 to 124 mm 2800 mm 5 pcs yes yes 14935
125 to 129 mm 2800 mm 5 pcs yes yes 16137

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