Leaking stuffing box?
Jul 8, 2019 9:37:20 GMT
Post by jy51 on Jul 8, 2019 9:37:20 GMT
Having waited the best part of a month on a marina berth for someone to carry out warranty work I decided to go day sailing this weekend. We slowly motored out of the marina and unfurled the sails, once set we stopped the engine, moved the gear lever into reverse to close our flex-o-fold propellor then back into neutral.
We sailed close hauled on a starboard tack for about 45 minutes before bringing the boat onto the opposite tack. We were making about 6 to 7 knots in a light breeze leaning at no more than 10 to 15 degrees when we heard the keel located bilge pump operating. We were taking in sea water, we found a convenient spot and set the anchor. On closer inspection we found the sump below the engine bed full to the top with sea water which seemed to be coming down from the tray under the stuffing box, we have shaft not sail drive. When healed, the water had over flowed and found a route down to the pump. We emptied about 30 litres of water and inspected all the bilge. No more water was entering the boat. The source of water had to come from around the engine as every other part of the bilge was dry other than the route down to the pump. I examined the raw water intake side of the engine and the water strainer, all was dry.
Once fully dried we started the engine and engaged forward and then reverse, no water entered through the stuffing box and the boat stayed dry. We motored back to the marina changing though different revs to see if a vibration set in that could have caused the box to leak, but nothing, we arrived back at the marina with a dry sump and bilge. So what happened?
Why did the ingress of water just stop when we stopped sailing?
My only explanation although I am not familiar with shaft drives is that the stuffing box has a sea water intake that lubricates the seal. Could an object, plastic bag or something like that have attached itself to the through hull valve and starved the seal of water which then started to leak, until we brought the boat to a stop and the object dropped away. Our marina suffers from very bad fouling could something had been growing in the intake? And lastly would a restriction of lubricating water caused such an influx of water, I believe in about one and a half hours we had taken in a lot more than 50 litres of water.
Any better Ideas, anyone?
We sailed close hauled on a starboard tack for about 45 minutes before bringing the boat onto the opposite tack. We were making about 6 to 7 knots in a light breeze leaning at no more than 10 to 15 degrees when we heard the keel located bilge pump operating. We were taking in sea water, we found a convenient spot and set the anchor. On closer inspection we found the sump below the engine bed full to the top with sea water which seemed to be coming down from the tray under the stuffing box, we have shaft not sail drive. When healed, the water had over flowed and found a route down to the pump. We emptied about 30 litres of water and inspected all the bilge. No more water was entering the boat. The source of water had to come from around the engine as every other part of the bilge was dry other than the route down to the pump. I examined the raw water intake side of the engine and the water strainer, all was dry.
Once fully dried we started the engine and engaged forward and then reverse, no water entered through the stuffing box and the boat stayed dry. We motored back to the marina changing though different revs to see if a vibration set in that could have caused the box to leak, but nothing, we arrived back at the marina with a dry sump and bilge. So what happened?
Why did the ingress of water just stop when we stopped sailing?
My only explanation although I am not familiar with shaft drives is that the stuffing box has a sea water intake that lubricates the seal. Could an object, plastic bag or something like that have attached itself to the through hull valve and starved the seal of water which then started to leak, until we brought the boat to a stop and the object dropped away. Our marina suffers from very bad fouling could something had been growing in the intake? And lastly would a restriction of lubricating water caused such an influx of water, I believe in about one and a half hours we had taken in a lot more than 50 litres of water.
Any better Ideas, anyone?
