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What are typical bow up angles for 58ft narrow boats?

Most boats have bow up angles. I have a 58ft trad, reverse set-up (galley at back), narrowboat. What should be the normal bow up angle range be.

Asked by: David Jones  | 4.01pm, Thursday 25 March


WW says:

I don--t think that there are any hard and fast rules on this - it is more about practicalities and personal preference. It also varies depending on how much water is in the tank at the front and how much diesel is in the tank at the back.
The main requirement is that the uxter plate - the plate that forms the underside of the counter - is just under the water line when the boat is at rest. When the boat moves forward, the propeller thrust makes the stern '€˜dig in-- by an inch or two but it should not be too far into the water or the boat will not swim so well. Conversely, when the boat reverses, the underside of the counter should still be under water otherwise the propeller will draw in air which makes it less efficient. This is known as ventilation and not cavitation which is something quite different. It is therefore a matter of trimming the boat so that the uxter plate is at the right level in most circumstances.
To help you do this, many boatbuilders design the stern so that it is sitting at the right level when the hole in the rudder plate is half submerged. You will also find that the uxter plate of many boats rises slightly towards the rear of the boat so that, when the boat is sitting slightly nose-up, it is level with the surface of the water.
Trimming the boat should also take account of the position of drain holes in the hull in relation to the water level to ensure that they are not too close. Provided all these requirements are met, you can then decide whether you like the boat cruising along with its nose in the air or, like me, you prefer it almost level which gives it a more purposeful look.

Graham Booth  | 12.01PM, Friday 26 March

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