Weed, plastic bags etc being sucked onto the engine water skin fitting

[Leisure 27]

A few years ago I was leaving Dartmouth when the engine overheating siren and light came on. The lifeboat towed me in. the next day the engineer could not find anything wrong with the engine and said it was probably something blocking the engine water skin fitting which had then floated off. Last week the same thing happened surprisingly twice in half an hour. I then motored for 9 hours. AS anyone come up with a way to help stop this.I was thinking of having some kind of stainless steel spiky thing made to stop all water being blocked from the engine and that the weed would float off quicker.

 

[[70521]]

Nope! I keep my tools close at hand to remove the clips, pull the hose and stick a screwdriver down through the skin fitting to clear the obstruction.

It is the first thing I check when the temp alarm goes off.

 

[capnsensible]

I've found most stuff like plastic just drops off when the boat stops. Can be handy though to take the hose off the inlet to the seawater pump and blow back through with your dinghy pump. Proves the line quickly.

 

[Tranona]

If you can use an above the water Vetus type filter and position it immediately above the seacock. Then you can take the top off the filter and rod down or use a dinghy pump. Managed to do this on the last engine installation I did although never had a blockage.

 

[Leisure 27]

Thanks, Sandy, If it does not float off I will try that. I will need to lie on the engine which will be red hot for ages. I will be near upside down. because it is really hard to get at. Why will it not float off when the engine stops? But worth a try. Any other suggestions please. I was hoping for something to stop this from happening.

 

[[70521]]

Thanks, Sandy, If it does not float off I will try that. I will need to lie on the engine which will be red hot for ages. I will be near upside down. because it is really hard to get at. Why will it not float off when the engine stops? But worth a try. Any other suggestions please. I was hoping for something to stop this from happening.

I am so glad the people who designed my boat engineered all those little 'challenges' out.

 

[The Q]

My motorboats water intake. Is a tube that extends from the bottom of the boat to above the waterline. You can unscrew the cap remove the strainer, poke a rod down the hole to clear it. Then reinsert the cleaned filter, and put the cap on.
I've no idea of its origin as the boat is over 50 years old..

 

[Tranona]

I was hoping for something to stop this from happening.

No simple solution except to only motor where there is no debris! Many people go for years and never pick anything up - just luck. Inevitably as the engine is sucking water through the intake it tends to suck up anything that happens to be close to the hull at that point. in the past grilles over the intake were popular but they really did not solve the problem and often made it worse so rarely fitted now. My suggestion on post#4 is effective and often seen in boats that are used regularly in weedy water like the French canals. However not always easy to arrange. In fact the boat I am refitting and installing a new engine now has the water intake a long way from the strainer and accessed through a hatch in the cockpit floor, plus it turns 90 degrees after the seacock. Hoping I will be able to move it into the engine bay immediately above the filter.

 

[westhinder]

I had the problem twice last year, twice weed sucked into the inlet and blocking it completely. Rodding through is no option as there is a 90° elbow on the through hull. Using the dinghy pump to blow the weed out did not help. Finally solved it using a garden hose at full pressure pressed hard into the inlet hose on the inside.
That’s fine in the marina of course, it won’t work at sea, I realise.

 

[iantomlinson]

Not had that problem in dartmouth yet. Been there 8 years but before we go anywhere we clear the filter from the top. Not seen much rubbish in the dart. Best of luck.

 

[awol]

A few years ago I was leaving Dartmouth when the engine overheating siren and light came on. The lifeboat towed me in.

I wasn't there. I don't know the weather, the area or any other conditions. But my first reaction was less than generous at the juxtaposition of alarm and lifeboat. I've cleared weed, plastic bags, worst was probably a Lions Mane jellyfish - I've even anchored in a narrow dredged shipping channel while replacing an impeller (but I did inform Port Control). So far I have not needed a lifeboat (or an engineer) to rescue me.

 

[Neeves]

You would usually catch such debris when motoring - moving ahead. Ignore the alarm for a few seconds and run the vessel in hard astern. Not only are you moving in the opposite direction during which you caught the debris but the prop is 'washing' the hull.

The other option is to accept the realities of life and have two separate hull fittings with a 'Y' valve. If the engine over heats switch to the other inlet. If the alarm continues you have a real problem - other wise continue on your passage and clear the blockage as Tranona has suggested.

We have a cat and I am able to blow down the water intake hose (no dinghy pump needed) - but this would not work if a bag has been sucked into the water intake, as opposed to simply sitting on the hull.

There was a similar thread on this very topic a couple of weeks ago - but I forget the title.

Jonathan

 

[DJE]

You would usually catch such debris when motoring - moving ahead. Ignore the alarm for a few seconds and run the vessel in hard astern. Not only are you moving in the opposite direction during which you caught the debris but the prop is 'washing' the hull.

The other option is to accept the realities of life and have two separate hull fittings with a 'Y' valve. If the engine over heats switch to the other inlet. If the alarm continues you have a real problem - other wise continue on your passage and clear the blockage as Tranona has suggested.

We have a cat and I am able to blow down the water intake hose (no dinghy pump needed) - but this would not work if a bag has been sucked into the water intake, as opposed to simply sitting on the hull.

There was a similar thread on this very topic a couple of weeks ago - but I forget the title.

Jonathan

We have a saildrive leg and find that a good blast of astern is effective in clearing weed or other debris from the cooling water inlets.

 

[PetiteFleur]

We also had this issue last week - water temperature alarm went off - turned engine off for a few minutes, restarted the engine and it was fine.

 

[ChromeDome]

An earlier thread about the same:
Seawater intake blockage

 

[johnalison]

We have a saildrive leg and find that a good blast of astern is effective in clearing weed or other debris from the cooling water inlets.

I think that a saildrive, being deeper, is a little less likely to pick up weed, though in my experience not immune. I have picked up weed from time to time on the prop, and usually cleared it with reverse as you describe, but we did suck up weed once, in Salcombe, and no amount of reverse dinghy-pumping had any effect. Fortunately, someone nearby was equipped and willing to dive to clear it. I could reach the prop with a boathook from a dinghy on our shaft-driven Sadler 29, but the saildrive is way too far away.

 

[Kwik Decision]

Thanks, Sandy, If it does not float off I will try that. I will need to lie on the engine which will be red hot for ages. I will be near upside down. because it is really hard to get at. Why will it not float off when the engine stops? But worth a try. Any other suggestions please. I was hoping for something to stop this from happening.

I strongly recommend fitting one of these, so you will get a much faster indication of the loss of cooling water, and avoid the engine overheating. I fitted one after a friend picked up a load of weed, and lost cooling water. By the time the engine overheat alarm had gone off, they had melted a hole in the silencer box, resulting in the bilge alarm going off shortly after sorting out the weed problem...

SM010

 

[seumask]

I second the silicon Marine exhaust alarm, fitted one recently and IMHO it was not too difficult.

 

[alahol2]

Or fit one of these... Thermostat
with a piezo sounder.

 

[richarddaltry]

We blocked our sail drive with a big mat of weed last year coming out of Newtown Creek. Managed to clear it with our paddle board pump fitted into the strainer inlet with some insulating tape. Now keep that to hand. I think the paddle board pump is probably superior to usual foot pump as suspect it moves a bit more volume. Took a lot of pumping to clear it though.