A watery puzzle

Caliban

Well-Known Member
Joined
7 Jan 2013
Messages
1,195
Location
Doncaster
Visit site
I have a most bewildering puzzle.
During the winter months I have been going down to the boat on my days off and firing up the engine. I have been out a couple of times just a mile or so up the river.

To the puzzle then.
The boat in question a Fairline 23, Volvo 145 going to a 280 o/d. The engine sits atop a couple of stringers as you would expect. My bilge is always dry.

After I run the engine in the marina and just tick over for a while I am getting a very small amount of water gathering either side of these stringers; not under the engine, but between stringer and hull. It is maybe a cupful on each side, it does not appear while the engine is running nor after the engine has been run, nor does it appear several hours later when I leave the boat. The following day when I open the engine compartment there is this water. Try as I might I cannot see where it is coming from, and I have really looked hard and from every concievable angle with the engine running, and switched off.
But the plot thickens. On the occasions when I have gone out for a short run this water does not appear, even though the engine has been running for longer and there has been movement through the water. Nice dry bilges the following day.
A couple of cupfuls of water does not bother me, but nonetheless I would dearly like to know what is going on here.

If anyone has any ideas I would like to hear them.
 
Condensation? As the temperature drops overnight, the moisture in the warm air inside the engine compartment condenses on the cold sides, accumulating by the time you next look at it.

It can only be that, or rain water getting in somewhere if you are convinced it's not coming from anywhere in the engine.
 
Condensation? As the temperature drops overnight, the moisture in the warm air inside the engine compartment condenses on the cold sides, accumulating by the time you next look at it.

It can only be that, or rain water getting in somewhere if you are convinced it's not coming from anywhere in the engine.
This crossed my mind, but the bilge directly under the engine is dry

[EDIT] By that I mean that I would expect water from the inside of the transom to gather under the engine
 
Last edited:
Are there any tell tale track marks to show where the water has flowed from?

You could put a thin line of e.g. talc around the area, and see where it gets washed away to give you some clues as to where it's coming from if not condensation.
 
Are there any tell tale track marks to show where the water has flowed from?

You could put a thin line of e.g. talc around the area, and see where it gets washed away to give you some clues as to where it's coming from if not condensation.
No tracks, but I love te idea of the talc, I'll try that tomorrow. Many thanks for that
 
My bilge/engine bay is also usually dry. (Sealine S23).
But occasionally some water collects. In my case the floor each side of the engine drains to the oil catch area under the engine. I cleaned some water out last week.
In my case I think the recent snow may well have built up in one or possibly both of the air intakes, blocked the drain from the intake - then directed thawed water into the engine bay.
It might be worth checking the air intake vents are draining okay if , like mine, the design has a potential to collect water.



.
 
i had a similar problem a few years ago with a Fairline T34. The problem got worse and drove me nuts trying to track it down. The problem was eventually found to be the gunwhale band which when removed could be seen to have more holes drilled in the hull than were used to fix the gunwhale band. The unused holes were plugged and problem solved. The use of talc or similar around the engine bay sides should show where the water is tracking from.
 
i had a similar problem a few years ago with a Fairline T34. The problem got worse and drove me nuts trying to track it down. The problem was eventually found to be the gunwhale band which when removed could be seen to have more holes drilled in the hull than were used to fix the gunwhale band. The unused holes were plugged and problem solved. The use of talc or similar around the engine bay sides should show where the water is tracking from.

could indeed be rain water leak that runs down to engine stringers after a run out. Talc works well to discover where a leak is coming from, but nothing beats a good poke around IMO, I would suggest giving the decks a good dousing with a hose by a willing crew member while you watch the engine room...
 
I'm almost certain the water is not from weather conditions.
The coincidence of this only occuring on days after the engine has been run, and not everytime it rains, leads me to this conclusion.

But certainly, I will give the decks a good dousing while I am there tomorrow.

No calorifier to check.

Thanks everyone for the ideas to date.
 
I have had water coming in through the side glass seal, down behind the settee seat back, then into the engine bay. Captains Creeping Crack Cure on the seal worked.
 
Condensation? As the temperature drops overnight, the moisture in the warm air inside the engine compartment condenses on the cold sides, accumulating by the time you next look at it.

It can only be that, or rain water getting in somewhere if you are convinced it's not coming from anywhere in the engine.

+1
I'd guess at condensation, with the vibration from the engine running dislodging it from elsewhere, to collect in the bilge.
 
Top