CHAPTER 4 Stuffing-box stern gland Grease feed tube


Packing material


Compressor ring To engine


Flexible hose mount


Adjustable bolts


The traditional stuffing box


Here, the seal is supplied by specially made waxed rope packing. This is cut into lengths equal to the shaft’s circumference, wrapped around it in the form of rings, slipped into the tube and bedded down by a compression nut which encompasses the whole shaft. This is secured by an equally large locking nut. Instead of a single packing nut, larger craft may have an oval flange tightened down by a pair of smaller nuts onto a similar flange fixed on the stuffing-box body. In either case, the packing is often greased by means of a remotely mounted grease gun. Such an arrangement will, if properly adjusted, drip occasionally while in use. If the dripping becomes too persistent, the first action is to pump a shot or two of grease into the packing. If this fails, the next stage is to slacken away the lock nut and carefully tighten the packing nut. Too much enthusiasm here can leave the shaft tight, overheated and ultimately suffering damage. Tighten it down gently, ideally feeling to see if the shaft can still be turned by hand with the gears in neutral. If tightening the packing does not stop the leak, cut a couple of fresh packing rings from the ship’s supply.


Each turn must be a separate ring. Now back off the nut and slip in the extra packing. Tighten down the nut again and give it some grease. Unless the original packing has totally disintegrated this can be achieved without fear of an inundation, but it makes sense to cut the rings first. Should the stuffing box fail altogether, you must try to caulk the gap as best you may. This can generally be managed within the capacity of a well-found boat’s pumps until harbour is reached and the vessel hauled.


It should be clear from the above that every skipper must be familiar with the stern tube arrangements on his or her boat. If the stern gland is of the stuffing box variety, spare packing must be carried, and it is essential that any tools required are readily to hand. This is especially true in the case of the stuffing-box nut, because these are often by far the biggest on board. A hefty adjustable spanner may well be the answer or, in an emergency, a ‘stilson’ or pipe wrench, but bear in mind that the nut must be held while the lock nut is tightened, so some means of achieving this must also be contrived. Finally, make sure there is room for your spanner between the nut and the ship’s side before you have to find out the hard way.


MANUAL OF SEAMANSHIP | 35


Power units


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172