2 ENGINES AND PROPULSION


Over the last decade or so there has been a rush of development. Modern stern glands need no adjustment and shouldn’t leak at all. The most popular types fall into two categories – ‘lip seals’ and ‘face seals’, both offered by various manufacturers.


Lip seals:


These work in a similar way to the oil seals in your engine. A thin rubber lip (or lips, there could be more than one) presses against the shaft in such a manner that the water pressure holds the two close together. Because the contact area is small, there’s hardly any friction. Lip seals are essentially water lubricated but some types need an


occasional squirt of grease to help them along. Face seals:


These employ an entirely different principle. The seal is made in two parts. One part is a polished stainless steel ring that’s clamped to the shaft and rotates with it. The second comprises another ring – this time of graphite – which is held pressed against the first ring by a rubber bellows clamped to the protruding end of the stern tube. This, of course, remains static. The faces of the two rings slide one against the other with very little friction. Face seals are always water lubricated.


Carbon ring


Water feed


Face plate rotates with shaft


Lip seals


Prop shaft


Lip seal type stern gland


Prop shaft


With either type of seal it’s important to acquaint yourself with what maintenance they need to keep them healthy. Because they don’t demand much attention it’s all too easy to neglect them. They will last for years if treated properly.


16


RYA Seamanship for Sea Anglers


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