Mystery leak

Paul Macloy

Yacht is finally back on the new mooring and has an accompanying water leak. 
It's not there all the time and was between 2 - 20 lt a day. 
Long story short... It's the lines that raise and lower the center board. The water line is higher than I remember and it almost at the top of the center board casing. The lower line is just on water line and if I put a little more weight on starboard side it's doesn't leak at all. 
So does anyone else have this problem and how to seal them? Tomorrow I'll try running them thru Rubber seals (bath plugs 😂) and hopefully that stops most of it. 


What model of TT do you have?

Paul Macloy

TT720. It's been over built to 28"
Not sure if the center board case is standard height and my yacht sits a little lower in the water? 

David Romero

Hello Paul,

How are the control lines led back to the cockpit? On the plans they are led through a channel from where the lines exit the c'board case up to the fwd cockpit on a 45 degree angle. This channel is made of plywood and epoxied on each end to the c'board case and cabin bulkhead so that it's completely waterproof. I modified mine so that the channel runs horizontally to the forward/interior of the cabin bulkhead, then turns upward through another plywood channel to a turning block mounted through the cabin bulkhead. This modification allows better access to the area under the counter and also provides footing for entry and exit of the cabin. I can't envision any other arrangement that would provide complete prevention of water intrusion. 


Try Flying

First suspect is always the c/b pivot as it below waterline and thus under pressure.
Couple things:

  • Your waterline is definitely higher up the case than mine and I did have a leak at this junction of the case and channel when I rebuilt it however I only had a leak when sailing at speed which creates a pressure point and raises the w/l inside the case.
    • I have a hard diverter mounted below the ropes to slow this gush of water ... will dig up pics but will not stop a leak
    • I eventually found the place I have missed when gluing in my case.. lots of glue mix fairing and tape
  • 20L seems more likely to be a pivot leak.. that is a lot however even a slow weep will give you a few liters over 24Hr so in some ways this might help you find it easier
    • draw some chalk lines or some other water soluble marker around suspect areas on both sides of the case to see if the leak washes one or the other off... might narrow down your search
Is the leak just will moored... this is pretty serious as it will get much works when under sail due to the increased pressure. You might need to spend the day on the boat with some chalk a flashlight and a beer to sus it out

Good luck

Try Flying

Had a closer look at your pic..... our setup is a much larger box section that slopes up to the cockpit. This box section where it met the case is where I had my issue and thus was able to run tape up into this to create a seal. In the rear of the case is a 25mm ss rod that is a snug fit and has threads into it each side. In this way it can be squeezed by bolts each side of the case and seal itself. The control lines run under this to redirect up the sloping box channel. I mention this as it too can be a leak spot.
When we are scooting along you can get water pushed all the way up into the cockpit with some force so its kinda important for a full seal from the case up to the cockpit. 

Paul Macloy

Tightened center board bolt 1/4 turn and tested with few sheet of toilet paper, stayed dry. 

Took It out for a test sail on the weekend. All hell broke lose! Running down wind on starboard lean, ok. Run upwind on Port lean, bulge pump ran full time and only just kept up!  😂😂
Found a bolt hole was unplugged at water line in center board case and the seal along the top of the center board case top just pored the water in, buckets of it 😆
I've resealed the case top and brought the lines straight up and then across. 

My lines are in the galley, they don't lead to the cockpit. (I don't have a rear cabin) 

I've done a temporary fix but will replace the timber later with a plastic block