Help! At sea with overheating engine

[Mistroma]

Out of interest, why astern and ahead?

Worth a try in case something is in the hole and being locked in by combination of drag and suction. Could be a weird shape.

I don't think there was a grill on my previous boat's intake. I clearing one blockage by reversing and another by blowing back with the dinghy pump. The filter was just at water level and quite narrow, making a good fit for the Avon dinghy pump.

My previous boat als got a long piece of Visqueen sheeting around the front of the keel and back over the intake. Water flow stopped but drop in speed was easy to spot. Might not have realised if it had been a narrower strip. Reversing, building a little speed and then drifting allowed it to float clear.

 

[Neeves]

Worth a try in case something is in the hole and being locked in by combination of drag and suction. Could be a weird shape.

I don't think there was a grill on my previous boat's intake. I clearing one blockage by reversing and another by blowing back with the dinghy pump. The filter was just at water level and quite narrow, making a good fit for the Avon dinghy pump.

My previous boat als got a long piece of Visqueen sheeting around the front of the keel and back over the intake. Water flow stopped but drop in speed was easy to spot. Might not have realised if it had been a narrower strip. Reversing, building a little speed and then drifting allowed it to float clear.

I've lost the detail in the replies - but do you have a sail drive. Poly bags, and maybe see weed, wrapped round the drive will block water completely or restrict flow. Using reverse and forward could sometimes clear it. It, poly bags, was a common problem in HK (and you have mentioned 'dirty marina water'.

Simply using reverse momentarily is not always enough - you need flow over the intake(s) so the yacht has to move back wards at a decent speed.

Jonathan

 

[lustyd]

Can also try poking dinghy inflation pump into hose and pumping hard down the pipe

Maybe start with this before doing the messy version

 

[Mistroma]

I've lost the detail in the replies - but do you have a sail drive. Poly bags, and maybe see weed, wrapped round the drive will block water completely or restrict flow. Using reverse and forward could sometimes clear it. It, poly bags, was a common problem in HK (and you have mentioned 'dirty marina water'.

Simply using reverse momentarily is not always enough - you need flow over the intake(s) so the yacht has to move back wards at a decent speed.

Jonathan

Not a sail drive. My Southerly was designed for running the engine in very shallow water. Normal hole for skin fitting and then filter/sediment trap. I said "Reversing, building a little speed and then drifting allowed it to float clear" wrt the long thin sheet trailing back from the keel along the hull. A change in direction is simple enough and can sometimes work. I'd build up speed and then turn off the engine in the hope a different angle and lack of suction would help. Sometimes it did but often a quick blast was needed with the dinghy pump. We often manoeuvred in shallow water with the keel up and intake only 6-8" above the seabed. Blockages weren't that common but I did become quite good at clearing them quickly.

 

[ChromeDome]

I've seen double intakes on a single engine mobo (via one strainer as opposed the two below)


Owner was concerned about blockage, apparently the redundant setup worked for him.

 

[Slahm]

Might want to consider jumping in the ocean and cleaning off the intake regardless of whether it is working right now. Overheating accidentally can cost you a ton of money. Oh, and being stranded and all that sucks too.

Always look over the side at your exhaust for a few seconds after starting your engine, get to know what your water flow is supposed to look like at idle, and at speed. It really is worth knowing for when you are wondering why you are overheating.

 

[penfold]

I've seen double intakes on a single engine mobo (via one strainer as opposed the two below)
View attachment 163076

Owner was concerned about blockage, apparently the redundant setup worked for him.

A bit drastic, but if your mooring or marina has chronically rubbish-filled water it may be prudent.

 

[dolabriform]

A bit drastic, but if your mooring or marina has chronically rubbish-filled water it may be prudent.

My previous boat had a sail drive, and I added an extra intake just in case something got wrapped around it and blocked it.

 

[ianat182]

Not mentioned, but could your exhaust hose have delaminated and restricted the outflow of cooling water. I have had this occur and it is not immediately obvious unless you have an idea of water volume being exhausted.
Worst case is a backflow into the engine when fully blocked.
Hope you find the problem.

Ianat182

 

[Bilgediver]

Hi - I have a hot engine within 30 mins of leaving anchorage today. Battery charging and temp lights on. The coolant water is a good level but is warm. Strainer is clear. Impeller is good. Belt tension good. But the freshwater coolant reservoir is hot so there is clearly an overheating issue. Alternator is very hot. Water pump wheel hot. Heat exchanger and exhaust don’t feel over hot. I have had problems with the alternator it - needed to jump start the other day because (I later discovered) I had a loose earth on alternator (now repaired and 3 trouble free engine hours since) so it was not charging and not grounding the ignition circuit. Related or red herring?

Any advice on a) cause and b) get me home solution - about 30 miles from a port. There is of course no wind worth having but could probably get to an anchorage - just rather get to a harbour with mechanics and parts.

You say you only have warm coolant but have a hot drive belt and pulley.. have you tried by touch otheroarts of the engine to see if you can keep your hand on these. If this is possible then maybe there is a is a belt drive problem such as slipping due to incorrect tension but still ciculating coolant but at a reduced flow which could lead to overheating to different degrees depending how much slipping at the pump belt. Does the drive belt seem to be slack?