Making a draining deck for crusier

[OllyO]

My cruiser has a rubbish rear deck that consists of some alluminium plates sat on angle iron. As you can image it doesn't stop a drop of water from entering the bilge. I can't imagine why anybody thought this design was going to work but it is what it is.

 

I intend cut out all the angle and close in the circumference of the deck by approx 10" with some 5mm plate. To the inner circumference of this I intend to weld some channel to act as guttering. From the either side at the rear of this arrangement I'll weld in some rectangular hollow section, possibly 3"x2" or similar. This will then exit the hull on either side (and be welded in place). I'd like to use pretty decent size stock for this as I don't want to be clearing blockages very often. Would 3x2 be suitable?

 

The centre of the deck I was going to cover with that ply with hex grip on it (don't know the name).

 

I know this is a fairly standard method of doing things, can anyone foresee any problems? I really would like a dry bilge, it doesn't sit well with me have any water in there at all.

 

I have a slight leak from stern tube so have welded up a pan that sits beneath with its own aut bilge pump so that should be covered.

 

Do I need to vent the deck? I know condensation can build up a surprising amount of moisture.

 

Lastly, what's the best method of insulating the rear deck to reduce engine noise?

 

Thanks again

[OllyO]

Last question! What size channel do people generally use?

[Mike Jordan]

Hi Olly

Since you have the ability to weld I suggest that you use the method shown in the attached photos. Many cruiser sterns are fitted with self draining decks in this way. The drains can either be pipes as shown or simply run the channels through the back of the boat or sideways if it has an integral fuel tank. Some prefer to use chanel rather than angle but the system is the same.

There is an article with my name on it in the July 2014 edition of waterways World which shows how to keep the noise down at minimal cost, you can download it from the website for a modest cost.

Best of luck with the project.

Mike.

Edited August 25, 2015 by Mike Jordan

[Grebe]

Hex pattern stuff is called Treadmaster. Sheets are 1200mm x 900mm Think in terms of 70 quid for a sheet.

[OllyO]

Thanks to both, much appreciated.

 

Mike; I much prefer your design as it does away with heavy channel section. My boat will already require a lot of ballast at the bow as it doesn't sit well in the water and I was concerned that adding six odd meters of channel would not help things. It's cheaper in terms of steel as well.

 

I'll take a look at your article ie insulation. My original plan was a fairly crude one which was sandwiching some cellotex between ply and the deck itself. When I was bringing my boat down to the Avon after I bought it I had done a quick bodge by gluing some cellotex to the underside of the deck. I was really surprised how much of a difference it made (while it lasted!)

 

Any thoughts of venting the deck? I was thinking of welding up some low profile mushrooms.

This looks to be the stuff;

 

https://www.jastimber.co.uk/18mm-wagonboard-wbp-plywood

[Mike Jordan]

Hi Olly

When you look at the article you will see that most of the sound absorbing materials are expensive for not a lot of effect unless the decks are sealed down tight. The engine needs to breath so ventilation is a must at some point.If the engine can draw air from under the cabin thats great but if you are putting in air vents they need to be as small as possible and ideally be sound trapped to prevent the rattle of the diesel escaping. The cost of sealing the boards with foam strip is very cheap but hinging and providing locks hold the boards down takes time, effort, and a few pounds. If you hinge the boards as suggested the gas struts become a must to keep you safe. Any materials used as sound absorbers need to be fire proof and that tends to put up the price. The sound levels on the boat shown in the article were hugely reduced by just the few strips of self adhesive foam shown.

Mike.

Edited August 25, 2015 by Mike Jordan

[Bullfrog]

My view on the timber is "Hexagrip" by Lathams. Best if you can source locally 'cos carriage will cost you as much as the material. Cheaper stuff like "buffalo Board" turns to Weetabix quite quickly.

 

I "sound-proofed" my hatch cover using Mike Jordans method from the mag. article. It uses vehicle hinges, rugged locks, gas struts and neoprene tape round all the contact points. It has been remarkably successful, and as well as keeping the sound levels down, has also reduced the ingress of water via the channels. Thank you Mike for such a helpful article

 

I've not bothered to vent the deck boards. there are several other points where the engine hole can breathe eg where our electrics pass thru the bulkhead into the cabin, Run all this season without any over-heating probs.

[Mike Jordan]

Hi Bullfrog

I'm delighted to hear that you got a good result. The cost of 70 pounds for the bits looks like a bargain when you look at the cost of the special foam slabs. You seem to have used the same method of getting air for the engine as well - try it and see!

Mike

Edited August 25, 2015 by Mike Jordan

[David Mack]

 

This looks to be the stuff;

 

https://www.jastimber.co.uk/18mm-wagonboard-wbp-plywood

 

I wouldn't use that. The website says: "Our supplier says that this board is not guaranteed for permanent outdoor use" "

[Neil Smith]

Most cruiser sterns seem to have ventilation slots in the hull sides for engine breathing and battery gassing.

 

Neil.

[Grebe]

Grebe has a cruiser stern. The foreward upright for the guard-rail is also the column for the 'morse' control. The main upright is a channel with the edges folded over by 1" each side to offer allow a cover which carries the morse control to be fitted/removed, the bottom of the upright is open to the engine bay. By making/finishing the cover shorter than the channel there is ventialtion via the upright.

[Neil Smith]

Grebe has a cruiser stern. The foreward upright for the guard-rail is also the column for the 'morse' control. The main upright is a channel with the edges folded over by 1" each side to offer allow a cover which carries the morse control to be fitted/removed, the bottom of the upright is open to the engine bay. By making/finishing the cover shorter than the channel there is ventialtion via the upright.

Cant water get in between the cover and deck.

 

Neil