One Point could sink boat

Arminius

Arminius

Well-Known Member
Oct 30, 2019
1,061
Seattle
Boat Info
Bowrider 200 Select, 2003
Engines
5.0L MPI, 260 hp w/Alpha 1 Drive
I opened the blue One-Point valve on my raw water cooled Alpha One 5.0 in the water at the marina and was eventually surprised to hear the automatic bilge pump. The boat was sinking. I raised the outdrive but the water flow out of the one point valve in the bilge at bow end did not stop. Apparently, I had created a siphon and removal of the highest blue plug did not defeat it. My childhood neighbors had a fish bowl with a high waterfilled handle that goldfish could swim through and I guess that's what I had. I better shut the blue handle after 5 minutes but this leaves the seawater tube from the outdrive, around the top of the engine and down through the fuel cooler, full of water in any freeze. The check valve is not helping but also removing the lowest blue plug could. I guess I'll investigate further although trailering the boat seems like the best option.
 
I'm not sure I follow .....

Are you leaving the boat in the water but trying to drain all water from the engine/hoses/etc?

I'm less familiar with the Alpha but on the Bravo you could disconnect the line from the drive to the inlet on the sea pump and plug it, but you'd still have water in that hose that could freeze.

In your case the line from the drive is even longer?

I guess to do this properly, you'd need to do away with the outdrive water line and do a seacock so you could close it easily.
 
Arminius said:
I opened the blue One-Point valve on my raw water cooled Alpha One 5.0 in the water at the marina and was eventually surprised to hear the automatic bilge pump. The boat was sinking. I raised the outdrive but the water flow out of the one point valve in the bilge at bow end did not stop. Apparently, I had created a siphon and removal of the highest blue plug did not defeat it. My childhood neighbors had a fish bowl with a high waterfilled handle that goldfish could swim through and I guess that's what I had. I better shut the blue handle after 5 minutes but this leaves the seawater tube from the outdrive, around the top of the engine and down through the fuel cooler, full of water in any freeze. The check valve is not helping but also removing the lowest blue plug could. I guess I'll investigate further although trailering the boat seems like the best option.
Click to expand...
Check your impeller on the raw water pump. I bet you are missing vanes or it’s severely worn. A properly fitted impeller should block nearly all water flow when it’s not spinning.
 
If you first remove the blue plug from the t-stat housing and THEN open the drain, it may break the siphon. Try it that way and see what happens.

You could also take the inlet hose off the t-stat housing and suspend that high.
 
Lazy Daze said:
If you first remove the blue plug from the t-stat housing and THEN open the drain, it may break the siphon. Try it that way and see what happens.

You could also take the inlet hose off the t-stat housing and suspend that high.
Click to expand...
Thank you. It is unexpected. There are warnings in the book and even on the one point valve decal that failure to close the valve could result in sinking. Seems like getting the death penalty for blowing a stop sign though. As the weather gets miserable, I realize I better trailer the boat and probably put an impeller kit on my to-do list.
 
Blueone said:
I want to see a pic of the water filled handle that gold fish can swim thru :)
Click to expand...
I could not find the fish bowl although I was distracted by memories of the enormous breasts of my childhood friend's mom. There was a back window where we hoped to see her showering. We knew it was wrong but there was a rumor she was aware of us. Maybe these bowls were found to be harmful to fish or just too hard to clean. Here is an elevated portion of a bowl with fish in it:
 
Arminius said:
I could not find the fish bowl although I was distracted by memories of the enormous breasts of my childhood friend's mom. There was a back window where we hoped to see her showering. We knew it was wrong but there was a rumor she was aware of us. Maybe these bowls were found to be harmful to fish or just too hard to clean. Here is an elevated portion of a bowl with fish in it:
Click to expand...

Was your childhood friends name Stacy by any chance?
 
What size socket would I need to turn the crank on this 5.0 L to right to see if other sectors of impeller might stop flow? As to my friend's Mom, this was a little farm town and it was possible she got a kick out of showing the boys more than the fishbowl.
 
Just flip the kill switch and bump the engine. But the Alpha pumps don't block flow anywhere near as well as the Bravo pumps.
 
The crank bolt has a 5/8" head but I just bumped as you suggested. The flow continued. For reference, this impeller was replaced 2 years ago and never generates a temp or pressure warning. Warm-up produced 170 F on this 2003 5.0 L MPI. Water pump pressure measured at the power steering cooler at 2000 rpm was 5 psi. This may not be book but is typical.

I think this means the line from the outdrive, the water pump cooler, and the fuel pump cooler could be subject to freeze damage. The siphon from the outdrive should be closed off with the closing of the blue handle and could not refill above the level of the outdrive anyway.

Meanwhile, I'll pull the tube off the back of that water pump pressure gauge and see if that breaks the siphon. It should.
 
Did you try pulling the hose off at the thermostat as was suggested?

If you choose not to do that, cut a piece of tubing, stick it in the hole after removing the blue plug on the T-stat housing, then blow into it as hard as you can. Be careful not to pass out. You just need enough air to displace the water.

You could also build a plywood shelter around the cockpit and wire up some 100 watt incandescent lightbulbs to heat the area to above freezing temperatures. Make sure to mount the switch outside the plywood cover so as not to risk a spark that may ignite any possible fuel vapor.

If the boat is in the water it will take colder temperatures to freeze then when it is on land. Keep a water bottle sitting outside nearby and you will know how frozen the water is in your motor.
 
I mentioned pulling the inlet hose off at the t-stat - wrong info. With the 3-point drain system, the inlet hose is down at the water manifold. But one of the exhaust hoses at the T may work - or the certainly the power steering cooler.
 
In addition to One Point Draining and closing the valve, I think you would want to pour some antifreeze in if your Alpha One was laid up in the water where it gets really cold. Looking at the diagrams in the back of SM# 31, it is apparent that the One Point valve is 2 way, upon closing it opens the seawater inlet from the submerged outdrive pump to the circulation pump intake and the lines to the exhaust manifolds. Probably not critical areas but the block is not drained if the impeller is seeping. Water in the block rises to seawater level. The Bravo does have a seacock and a drain on the belt driven pump although I don't know if Bravos even have One Points. In real life, my covered slip came with a 110 outlet and my Select 200 has a closed engine box. A 100 Watt bulb would probably be more than enough.
 
Lazy Daze said:
I mentioned pulling the inlet hose off at the t-stat - wrong info. With the 3-point drain system, the inlet hose is down at the water manifold. But one of the exhaust hoses at the T may work - or the certainly the power steering cooler.
Click to expand...
I had "Y"ed a water pressure gauge to the power steering cooler electrical sensor fitting long ago but never found need to look at it. This gauge is mounted by the shift lever and the back is accessible so I can pull the tube off for the same outcome you suggest. I was just curious about this aspect of winterization given the expressions on the faces of the Marina operators when I told them I would use One Point.
 
If it's laid up in the water, and after draining the engine, there is no benefit to pouring AF into the outdrive. It will just wash away. The Alpha drive will drain itself - down to the water level, of course. If the water around the drive doesn't freeze, neither will the drive. Obviously this is not what would happen in real life, though, since the boat would be taken out if the water is going to freeze.
 
Arminius said:
I had "Y"ed a water pressure gauge to the power steering cooler electrical sensor fitting long ago but never found need to look at it. This gauge is mounted by the shift lever and the back is accessible so I can pull the tube off for the same outcome you suggest.
Click to expand...
That'll work.
 
In summary, the One Point system may fail to adequately drain an Alpha drive boat that is in the water. The owner may properly drain the engine for 5 minutes and then close the One Point. Unfortunately, water may flow back into outdrive, through the impeller, up and back down into the block by the siphon principle. Raising the drive to the trailering position did not defeat the siphon. Placing a "T" in the port under the water pressure sensor at the power steering cooler with a small valve to admit air worked for me. The black 3/16th" hose under the brass hex fitting leads to the valve in the image below.
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