Swim

[pwl]

I am looking at getting a boat after a long time having boating holidays. The literature indicates that lenght of swim has a significant effect on how the boat behaves but nothing I have read gives any indication on how the lenght of swim relates to the length of boat! I am looking at something about 63-68 feet. What would be a short / medium / long swim for that length of boat and doe it really make a difference?

 

P

[BlueStringPudding]

How's about a swim that tilts towards the front of the bilge not the stern? That means all bilge water collects at the furthest point from the bilge pump and needs to be mopped out by hand.

 

Or is that just a Black Pricne specification...?

[HYBRID]

Can you not move the bilge pump?

[carlt]

Or some heavy stuff (Kev's razzles, maybe) sternwards?

[Liam]

I, too, have a boat that kicks up at the back end so what water there is in there, rests agains the cabin bulkhead against going towards the weedhatch. Moved the pump a couple of feet, and hey presto!

 

The length of swim depends really and varies from builder to builder. There is no set ratio and I would not be put off a boat I liked because the swim was a foot shorter than another one next to it in the brokers yard.

[Supermalc]

'Topic' - I always thought it was to stop you drowning

[Keeping Up]

On Keeping Up, the swim itself is 9 feet from its point to where it meets the hull-sides. But of course it doesn't start right at the stern, there has to be room for the prop and the front half of the rudder so it starts 18 inches forward of the stern. Which means that the swim extends to a distance of 10 ft 6 in from the stern.

 

If you want to see an unusual design of swim see how the Tuesday Night Club designed their boat "Earnest" (scroll down about half way to see the pictures). Instead of the swim widening out to the hull sides, it stays narrow and instead the uxter plate slopes down to the baseplate rather like a slipper stern. Apparently it was extremely effective, in particular it allowed the boat to make porogress even when the water was so shallow that the propeller was half out of the water.

[Supermalc]

And you would do well to copy the design of Keeping Up. Without doubt the best handling NB I have been on.

[John Orentas]

Yes nine feet is usually considered an optimum swim length these days, for bow and stern.. There always a price to be paid however, there is a considerable loss of buoyancy which may need to be taken into account, no real problem for a cruising boat but I calculated that I was loosing over a ton of flotation.. You may notice a very significant lowering of the stern when underway.

[Yoda]

On Keeping Up, the swim itself is 9 feet from its point to where it meets the hull-sides. But of course it doesn't start right at the stern, there has to be room for the prop and the front half of the rudder so it starts 18 inches forward of the stern. Which means that the swim extends to a distance of 10 ft 6 in from the stern.

 

If you want to see an unusual design of swim see how the Tuesday Night Club designed their boat "Earnest" (scroll down about half way to see the pictures). Instead of the swim widening out to the hull sides, it stays narrow and instead the uxter plate slopes down to the baseplate rather like a slipper stern. Apparently it was extremely effective, in particular it allowed the boat to make porogress even when the water was so shallow that the propeller was half out of the water.

 

Has anyone got better pictures of the swim of this boat. The articles pictures are not that good. Please help!

[Liam]

[David Schweizer]

The swims on my boat are 15ft both ends which does compromise internal space a little, but it makes the boat look less like a floating box, and handling in reverse is much better than boats with less swim.

[pwl]

The swims on my boat are 15ft both ends which does compromise internal space a little, but it makes the boat look less like a floating box, and handling in reverse is much better than boats with less swim.

 

thanks to all. Our target boat has (at buest guess) only 6-8 foot 'swims' fore and aft. Sounds like she will be a bit of a pig

[Maverick]

I, too, have a boat that kicks up at the back end so what water there is in there, rests agains the cabin bulkhead against going towards the weedhatch. Moved the pump a couple of feet, and hey presto!

 

The length of swim depends really and varies from builder to builder. There is no set ratio and I would not be put off a boat I liked because the swim was a foot shorter than another one next to it in the brokers yard.

 

As you know Liam I have the same boat as you. Although I have my bilge pump at the front of the engine it never empties every drop out and the remains mixed with the old oil etc does not make for pleasent smells.

 

Getting to it is difficult due to lack of space but a few weeks ago I used the disposable nappy trick and soaked it all up. Looks and smells much better now. Had to manouver the pads in place with a brush stale and then remove them with a length of welding wire bent at the end to form a hook.

[Yoda]

 

Thanks Liam. Do you have a photo taken from the side as well as this one?

[Supermalc]

What constitutes a 'good' swim

 

Dover to calais .........

[magnetman]

One where when you get out of the water you don't feel like you've been bleached. Give me infusoria over chlorine any day.One where when you get out of the water you don't feel like you've been bleached. Give me infusoria over chlorine any day.

[Liam]

As you know Liam I have the same boat as you. Although I have my bilge pump at the front of the engine it never empties every drop out and the remains mixed with the old oil etc does not make for pleasent smells. Getting to it is difficult due to lack of space but a few weeks ago I used the disposable nappy trick and soaked it all up. Looks and smells much better now. Had to manouver the pads in place with a brush stale and then remove them with a length of welding wire bent at the end to form a hook.

Yes but as you should know, leaving some water in the bilges, and having a leaky gland is a good thing, ask John Orentas for confirmation <g>

 

Yoda, erm, how about this one? not a very good one but...

 

[Yoda]

Thanks, I've got more to study now. Just what I wanted.

[DHutch]

Emilyannes swim is around 10ft long, which works well for us.

- She is 58ft long, the std 6ft10 wide, and weighs in at around 22ton, giving a draught of around 2ft8 with a 26inch prop.

 

Pic at launch (click to enlarge)

 

And a pic at drydock this easter gone.

 

 

Daniel

[pwl]

Thanks to all. Having seen the prospect out of the water the swim is about 6-8 feet at the stern on 64 feet. Figures as she was built as a 10 berth. Now to await the survey results

 

P