Bilgeless boat and shaft seals

In the engine room of the boat I am building, there are no real bilge(s). The lower hull is the engine room floor. The recommended shaft seal is a Halyard style shaft seal which is an oil filled seal. They can be seen about half way down this page with pics and full description on how they work. Stern glands – Cox Engineering


There is no where for the water to go for a standard stern gland shaft seal. The way the rear of the hull is shaped, it's very difficult to access the shaft without pulling the engine and gear box which is cramped against a forward bulkhead. I've looked at various drippless shaft seals but they need 10+ inches between the shaft coupler and the stern tube. I will have at best 6 inches going by the calculations I have done. The other problem is cooling water for the drippless seals. There will be no water coming aboard the boat from outside the hull. The boat will be keel cooled with dry exhaust.


Anyone have any ideas for other shaft sealing arrangements? I looked at the UK barge and narrow boat shaft seals. They use a grease seal with a pressurized grease cup mounted above the seal. It's like a standard type packing gland but filled with silicone grease. These are short and would fit but they are mainly for smaller slow spinning shafts usually around 1 inch or smaller. I'm not sure about rpm limits but my engine is a low rpm engine. My shaft will be 2 inches as spec'd.

I think there's a reason Halyard Marine stopped making these seals. They were superseded by better methods/designs, and manufacturers. I would put a PSS seal in or similar and also make a false bilge under it with a strum box. A home made strum only needs a 1/4" to work. You also need a remote diaphragm pump.

Martin J said:

I think there's a reason Halyard Marine stopped making these seals. They were superseded by better methods/designs, and manufacturers. I would put a PSS seal in or similar and also make a false bilge under it with a strum box. A home made strum only needs a 1/4" to work. You also need a remote diaphragm pump.

Click to expand...

PSS is to long from the one I looked at. I'm planning a call to them next week. The box under the shaft was a thought. I don't know yet if it's workable. The dead wood curves up right below the shaft and the sides roll into the deadwood right beside it. It would come out an awkward shape for sure.

2" shaft? Seems big. How much HP?

Nevermind. I see you are building a barge now. Thought you were stitch and glue plywood still.

Northern Spy said:

2" shaft? Seems big. How much HP?

Nevermind. I see you are building a barge now. Thought you were stitch and glue plywood still.

Click to expand...

Yeah I decided to abandon the idea of a trailer boat. I only see me trailering this boat two maybe three times over my life time. I figure I better go with comfort over mobility seeing as how I'm planning to spend at least 10 years living aboard.


The engine is a Cummins 3.9L 4BT 150hp variant. The shaft is a total of roughly 4.5 feet long and spinning a 22 inch prop. 316SS is spec'd and the large side was spec'd for canals around Europe where the water depths are shallow and the possibility of dragging the hull through mud and debris is high. I could probably go down to 1.25-1.5 and use a newer type shaft material. I would feel a bit more secure with the 2 inch shaft in there.