small leak in my tender

With mine, I dropped it off at Ron Hale Marine in Portsmouth, and said "There's a small leak in my tender, please fix it".
£50 and a couple of days later, it's fixed.

The alternative would have been trying to wrestle the tender into the bath?
 
blow up hard and splash water with a bit of w/up liquid in it over small areas at a time.

My first action, though, would be to take out the valves, rinse them and their seats / flaps free of any sand or mud.

Polymarine make good repair kits quite cheaply, but the best thing is scavenge an old inflatable of the same material from a skip. This will give you masses of hypalon or butyl or pvc. You then only need to buy the 2 part adhesive. The job's easy if a bit fiddly.

http://www.polymarine.com/
 
Instead of pumping it full of air, fill it up with water and see where the water escapes. You may have to dismantle the valve and take the no return part out. Good luck....
 
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