Laminated pipes instead of self drain seacocks

Dear forum
I am rebuilding the cockpit sole in my 29 ft sailboat and have come to the installation of new self draining. The entire sole is new, and in this state of things its just a flat panel/floor, through which I will drill the self draining holes.
Now, the obvious thing would be two holes with self draining nipples and hose that lead to two seacocks, perhaps crossed. This however has some disadvantages: the seacocks take up a lot of space, and they would end up in extreme angles, due to the shape of the hull.
A fellow clubmember suggested another solution, which he has built. He is a seasoned blue water sailor and I listen carefully to his advice. He suggests I should do away with hose and seacocks altogether and instead laminate two generous grp-pipes from the cockpit sole and vertically down through the hull. This would have the clear advantage of not having to worry about the seacocks and their sealant to the hull etc. I would also have a clean shot down through the pipes to the water, making it dead easy to clear the drains of any growth or other.
I am tempted to do this, and believe that I have in me, or at close hand, the knowledge to build it strong and safe.
One very important element is, naturally, to build the pipes next to, and laminated to, a strong wall that connects the cockpit sole to the hull, in order to avoid flexing that might cause cracks.
Another aspect worth knowing is that the pipes would live entirely in their own private compartment, with strong walls on three sides and a sturdy, watertight hatch on the fourth. There will be no risk of heavy objects come flying at them, and should they mysteriously crack then the small compartment would be filled up and nothing else.
So my questions are:
Firstly: Is this a sound and safe solution?
Secondly: Lets say it is, will I run in to legal problems in any way? In my country, Sweden, we sail around in pretty much any old contraption of a vessel and there is no such thing as inspections or legal demands, as long as you dont race or sell boats commercially.
But could I get in to trouble applying for cruising permits in, say, the USA?

Just to be clear on the legal side of things: I understand there are norms and regulations for boatbuilding and they serve as good guidelines for us who build privately, for ourselves. My concern is whether I might end up not being allowed into a country due to not fullfilling regulations concerning seacocks.
Note also that my first concern and what I want to establish is whether it is a good idea to buid this or not.

Advice much appreciated.

Per Runhammar/Stockholm

 

Can you post a photo or two showing the aft end of your sailboat please?

I am wondering if it would be feasible to run your cockpit drains out from the aft end of the cockpit to through hull fittings in the hull above the waterline?
This is what I did with our 35' sailing boat 25 years ago, as I did not like having 1.5" diameter seacocks in the depths of the cockpit lockers that had to remain open all the time so that rainwater could drain.
Although one disadvantage of this arrangement is that if you are well heeled over, water comes up through the leeward drain and you get some water in the cockpit.
But to me this minor inconvenience is worth having.

 

Thank you for our suggestion, Bajansailor. However, leading drains out over the waterline is not doable in my boat. If I lead them aft they would block valuable access to the lazarette, which I need. Leadingt them out to the sides would ruin space in the quarter birth.
The main advantages of the ”pipe”-solution for me would be:
1 Clean shot down through the pipe into the water for cleaning and remove blockage.
2 Space requiered much less than two bulky seacocks.
3 No issues with leaking sealant etc around seacocks.
So the advantages are clear to me, but I am asking for input on the safety of the solution, compared with hose and seacocks.

 

It is not ideal. However, if you do, make sure the pipe is not straight. It should have either an "s" shape or a couple of bends. Otherwise, you will have a concentrated stress which may cause structural issues and sink the boat.

 

Gonzo, Will I get that even if the pipe is laminated to a bulkhead (or rather a small wall underneith the cockpit sole) all along its length, like I describe in the text? I would assume the pipe becomes like an integral part of the partition (wall) and would not make an impact separately on the hull laminate.

 

I visualize it as a column connecting the bottom of the cockpit to the hull.

 

Aha, no, its more thought to be a column laminated along a wall under the cockpit, connecting the cockpit to the hull. I do understand that a single pipe leading down from one flat surface to the hull would cause stress and cracks.

 

I cannot draw to save my life, but perhaps this will clarify. Seen from above, a cut through of the intended installation. The two ”eyes” are the two pipes and the thick line is the wall that separates the intended flood chamber from the rest of the space underneith the cockpit.

 

If that is a structural bulkhead, there will probably be no issues with a stress concentration.

 

That is my thinking. Now the remaining issue is whether I have any other safety concerns installing open pipes rather than seacocks that can be closed. And the legal aspect.

 

How are you making the connection to the hull. You can't just glass it in. You still need proper preformed flanges that get bogged to the hull and the sole and project through the panels and insert into the pipe and hose. These should each be as strong as the hull. Then you can bond to these and tab to the bulkhead and fillet the outside of the pipe. But it is a total waste of time and effort in my opinion. I had a Cal 28 that had been modded. The original cockpit drain exits had been abandoned and the hoses routed to the abandoned z drive water supplies. What I found after a couple of years ownership and 4 major Florida hurricanes was that the old 2" transom exits were glassed over with a 3" x 3" piece of 10oz cloth (and bottom paint), and that the drain hoses had no clamps on them at all. They were just pushed onto the barbs. That sold me on hoses.

 

A fillet around the pipe end and generous tabbing should work fine. There are many installations like that. For example, propeller shaft tube , rudder shaft tubes and exhaust pipes.

 

Well, yes, I planned on just glassing the pipes to the hull. Why is that not enough? Im thinking a generous fillet on the inside with high density filler and plenty of 450 grams biaxial both to bond the pipes to the hull and to the structural bulkhead. Tunnels for bow thrusters are made like this and they seem safe. Admittedly, they lead from ”ocean to ocean” but still. If their fillets were prone to fail that would have been known.
Directly below where the holes will be in the cockpit, the hull slopes inward at a pretty steep angle, one from each side obviously. I think you get the picture. This means that two seacocks installed there would point at 45 degrees inwards and the connected hoses would have to be like two crossed swords, leading to one self draining flange each. Its doable, but I kind of warmed to the idea of straight holes and no seacocks.
It should also be said that the pipe-solution would allow me to place the adjacent bulkhead three inches further aft, which enlarges the space for the diesel tank and, by the standard tanks I am choosing between, means the difference between a 45 litre tank and a 70 litre tank. Sorry about the metrics.

 

Why is the proposed arrangement not common?

 

Exactly! Why? Or maybe it will be from now on. Maybe people will talk about ”before and after” Runhammars post about the pipe-arrangement.