scuppers and trunks

codprawn · 02 January 2005, 17:36

Yes I know it has been covered quite a few times in the past but wouldn't mind an update - the time has come for me to decide what are the best transom drains!!!

On a deep V hull I suppose the lower the drain the better - I was thinking about a trunk type backed up with 2 ball type valves - anyone know the best make and place to buy these valves from???

I know elephants trunks work but are there any preffered setups? Some commercial rescue boats seem to have moulded rubber ones that look a lot more purposefull than the normal bit of tubing.

Obviously the ultimate would be no transom at all but can't afford an Ocean Dynamics boat yet and I don't think my outboard would last very long if I started cutting out chunks with a chainsaw!!!

Pete7 · 02 January 2005, 21:24

The beauty of the elephant trunks is they are so simple, whilst the ball thingys don't seem to do to well if you spill petrol on the deck. Since your building a new boat worth thinking about having two fitted (bit like girls with shoes, you can never have enough

) as the cost is minimal during the build stage.

Pete

tue · 03 January 2005, 10:06

I have 2 of the ball things. I got them from international Marine Supplies. They seem to work for me, but are situated at deck level and above the water line. I have fitted a ball type to another RIB at work which is below the water line and at rest there were no leaks coming in. Don't know what it'll be like after 6 months underwater though when it gets a little fouled.

Andy · 03 January 2005, 10:31

This sounds obvious BUT: Make sure the trunk is long enough that when in the up position in a loaded boat its above the water line. A humber our dive club owned used to sit on the dive site taking on water as the trunk did not clear the water as i should have! Even slight waves would lap over the top.

codprawn · 03 January 2005, 12:39

Quote:

Originally Posted by tue

I have 2 of the ball things. I got them from international Marine Supplies. They seem to work for me, but are situated at deck level and above the water line. I have fitted a ball type to another RIB at work which is below the water line and at rest there were no leaks coming in. Don't know what it'll be like after 6 months underwater though when it gets a little fouled.

Some of the ones I have seen are easily removed for cleaning - just a quick twist of the cover.

Have you got a link to the people you bought them from???

Thanks!!!

Alan · 03 January 2005, 13:39

on the ping pong ball scuppers. As Pete7 says they don't survive any petrol spilt on the deck. What happens is that the gaskets in them harden when in contact with petrol and no longer form a tight seal around the ball and let water in at rest. I had them on my DS21 and they were a pain in the ring - the boat actually damn near sank in Dunstaffnage Marina once!

My preference would be for the tried and tested elephant trunk - pref two of them with a reasonable bore. Plus at least one, poss two decent sized electric bilge pumps. And a bucket. (The fastest method of clearing water from a flooded boat - a frightened man and a bucket!

)

Alan

codprawn · 03 January 2005, 14:12

As my boat is petrol then maybe I will avoid the ping pong ones - elephants trunks are pretty foolproof if they are long enough!!!

Boat will have 2 bilge pumps as it is being built to mca specs.

tue · 03 January 2005, 14:24

Quote:

Originally Posted by codprawn

Some of the ones I have seen are easily removed for cleaning - just a quick twist of the cover.

Have you got a link to the people you bought them from???

Thanks!!!

http://www.internationalmarinesupplies.co.uk/

codprawn · 03 January 2005, 14:53

Thanks - very useful site but can't find any of the drains!!! Prob stopped doing them.

Tim M · 08 January 2005, 19:44

I'm curious about this length business......

I've seen trunks which seem to be pretty standard and are probably what are all thinking of, whereby, there's a bit of hypalon glued into a tube shape which has to be kept up to avoid water entering the boat.

My trunks are flat (two pieces of pvc heat welded together), and are quite short (300mm ish). When the boat is at rest, they sit under water, but, because they are flat, water does not enter. However, when the boat is going on, they are not in the water, and so any water on deck drains out of them. This works really well, so why don’t' more people use them?!

codprawn · 09 January 2005, 11:56

Quote:

Originally Posted by Tim M

I'm curious about this length business......

I've seen trunks which seem to be pretty standard and are probably what are all thinking of, whereby, there's a bit of hypalon glued into a tube shape which has to be kept up to avoid water entering the boat.

My trunks are flat (two pieces of pvc heat welded together), and are quite short (300mm ish). When the boat is at rest, they sit under water, but, because they are flat, water does not enter. However, when the boat is going on, they are not in the water, and so any water on deck drains out of them. This works really well, so why don’t' more people use them?!

Know the type you mean - seen them on rescue boats although usually made of rubber - wondered how they worked!!! Look like the ideal setup - any chance of a piccy???

Tim M · 09 January 2005, 13:00

Pic:

Rogue Wave · 09 January 2005, 13:58

Quote:

Originally Posted by tue

I have fitted a ball type to another RIB at work which is below the water line and at rest there were no leaks coming in. Don't know what it'll be like after 6 months underwater though when it gets a little fouled.

I have found they do foul, we have em on the Gemini and it's a pain having to lean over the transom and immerse your arm in water to push the balls up to make the seal.

I have boat with trunks which I find ok and also our Scorpion has two rubber bung in the transom which is my favourite
Any chance of a Pic of your flat trunks Tim

Rogue Wave · 09 January 2005, 14:03

looks like aour posts crossed.

Do they have a device in them that keeps em closed or is it just the flat shape and if so will it keep it's tension over the years d'ya think

Tim M · 09 January 2005, 15:49

They just naturally keep their flat shape. Of course, when the boat's out of the water (which it is most of the time) gravity keeps them dangling down which helps to keep the shape. When the boat's in the water they tend to point upwards; again keeping a nice flat shape. Who knows how they'll be in a few years, but then they are very easy to change.

codprawn · 09 January 2005, 17:01

They do look like the same type as on the rescue boats - when I get a chance I will post the pics of the ones attached to a rescue boat on the Pride of Bilbao ferry.

ribraff · 09 January 2005, 17:39

If you are still wanting to go down the scupper route, speak to steve the boat, he does them through Nautequipe.

CJL · 09 January 2005, 20:16

A lot of the water companies use the flat trunks as shown in the picture, in the strom overflows. They rarely get blocked and can be a lot shorter as the rubber is thicker, (10mm) but they do have a lot more pressure behind them! Depending on the type and quality of the rubber these can last for ages with minimal maintenance.

I've seen some boats with a combination ball and trunk system in the commercial world. But this was on a boat with a very low transom and the trunk did fill when waves were at the right angle. It was a good compromise and did not seem to clog. That said they did have a huge trolley on railway lines to launch and recover so fixing a clog was a lot easier.

Chris