Check valve for transom thru hull on Catalina 30

[Project_Mayhem]

I have a Catalina 30 MKIII with the walk through transom. In medium waves, and especially when there's three or more people in the cockpit, water likes to come in. This means that water is likely entering the through hull for the steering components and dunking those components. The compartment needs a way to drain and a pump is an impractical failure point. A high "loop" would prevent draining. What are your thoughts on adding a check valve?

 

[Hayden Watson]

I have seen that type of water ingress on C30's often caused by rotten scupper hoses. Mine was one of those. New hoses helped a lot.

 

[Project_Mayhem]

The walk through transom doesn't have scuppers since the transom is open. There's a hose that goes from the transom to a compartment that houses the steering components. If the waterline is above that compartment, it stands to reason that water is flowing into it. Aside from occasional debris in the valve, can anyone think of any other reasons not to use a check valve or know of a better device/technique?

I currently have two bullet style non-marine valves on the sink through hulls. They work great but I would like something more robust. Has anyone seen any non-flapper style, marine grade check valves? I feel that the bullet style is lower maintenance and less prone to clogs

"Bullet" style check valve

 

[jssailem]

I always try to keep water from getting into the boat. Looking at your transom I am trying to understand where the water is coming from. If the boat is on her lines it seems the stern sits high and proud of the water surface.

I know when racing in small boats, that we put crew on the rail as the wind picked up, limiting cockpit crew to the helm and one sail trimmer.

 

[Project_Mayhem]

Water will reach the cockpit sole

 

[jssailem]

I am trying to understand the context of the problem.

Generally is it preferred not to put any device that could inhibit the flow of water in cockpit drain lines.

Is the issue an every time you go out on the lake issue, or is it a one off experience? There is a lot of free board between those drain holes and the water line. Perhaps if you had a pair of the 300lb plus linemen from the Chicago Bears sitting on the pulpit seats with you at the helm the boat would be dragging her butt low enough to induce water to backflow up the drain lines. Or if you were sailing in very heavy (5ft breaking) following seas I can see it occurring. But in normal sailing it seems unlikely. You might be better off installing larger drain lines.

I had a problem with my old prop. It had such a large bit into the water that it caused the stern of my boat to set 16” low in the water. When that happened the boat was pronounced out of balance being bow high. No water came up the drains but a black line of diesel exhaust was seen transom. I fixed that by getting a better prop which now drives the boat forward on her lines.

Your boat hull should be trimmed to cruise on her lines. When racing this usually means the crew serves as rail meat. It also means we move gear forward to balance fore & aft.

 

[Tally Ho]

If water can get into the compartment from the cockpit sole, and the hose just drains it out, what good does preventing “backflow“?

The steering components will still get wet (but at least you are in fresh water).

or have I misread the issue?

Greg

PS :-Getting itchy to get your boat in the water?

 

[Foswick]

I am also confused about the nature of the problem. As John points out, there is a quite a bit of freeboard. I would not expect water to come over the sole except maybe with breaking waves and following seas or perhaps when excessively heeled. Even if water is coming in through the through-hull, it won't prefer to travel upward from there. That is, it gets into the cockpit only because it starts somewhere above the cockpit floor and flows down ... or it is pressurized.

Now, I can see how a wave hitting that through-hull could briefly pressurize the contents of the tubing and cause water to spurt upward somewhere else. Is that what you are suspecting?

Even if so, we must be talking about just a little bit of water and it would drain right back out your open transom.

Or, am I not getting it?

 

[Project_Mayhem]

This boat has no scuppers as it's a semi open transom. The line I'm considering adding a backflow preventer connects the through hull to a separate compartment that houses the steering components. I'd like to keep those components dry if reasonably possible.

 

[Richard19068]

A high "loop" would prevent draining. What are your thoughts on adding a check valve?

My first thought is what's the worst that can happen with the check valve? If it gets stuck or fouled, water might get in but not back out?

How else does /can water get into that compartment?

 

[Davidasailor26]

How else does /can water get into that compartment?

I think that’s the part many of us aren’t understanding. It looks like the outlet on the transom is factory, so the boat is actually built to let water into that area somehow, and have it drain out a hose?

 

[Project_Mayhem]

There's a few ways water can enter the compartment. The first is if there access panel or screws on the access panel (part of the cockpit sole) is not sealed properly. The second, and one that's more concerning one, is through the through hole and hose that's meant for drainage. Lastly, If the rudder shaft seal is in poor condition, it could enter through there

 

[Foswick]

I understand water getting into the compartment. What I don't understand is how it goes uphill a pretty fair bit into the cockpit, from there. Maybe a really strong and highly localized tidal effect that follows you around? (I have something similar, only mine is just a grey cloud.)

 

[Davidasailor26]

There's a few ways water can enter the compartment. The first is if there access panel or screws on the access panel (part of the cockpit sole) is not sealed properly. The second, and one that's more concerning one, is through the through hole and hose that's meant for drainage. Lastly, If the rudder shaft seal is in poor condition, it could enter through there

Leaking screws or rudder shaft seal should be pretty unusual events. If water is backing up the hose on a pretty regular basis when underway I’d be tempted to put a shutoff valve in the hose. I’d close the valve whenever I opened the engine seacock, and open it when leaving the boat. That way water can’t back up when underway, but could still drain out if something catastrophic leaked and threatened to fill the compartment.

 

[Project_Mayhem]

Leaking screws or rudder shaft seal should be pretty unusual events. If water is backing up the hose on a pretty regular basis when underway I’d be tempted to put a shutoff valve in the hose. I’d close the valve whenever I opened the engine seacock, and open it when leaving the boat. That way water can’t back up when underway, but could still drain out if something catastrophic leaked and threatened to fill the compartment.

I've had several screws leak due to silicone being used as a sealant