On my 510 I have removed the keel bolts and discovered that double washers were used on 3 of the 6 bolts forward of the bilge sump, the keel has never been removed. The original bolts used were 30 X 90 mm on measuring the thickness of the hull and the two 7mm thick washers I determined that there was a total of 31mm of thread penetration into the keel, way below the required 1 1/2 times the dia of the bolt (45mm). I had ordered new Keel bolts prior to removing and beneteau sent me 30 x 120 mm I tried the bolts in the hole and discovered that the 120mm bolts went all the way down in the holes with prior single washers
on but found that the bolts became tight when they hardly entered the holes which had had two washers on, the reason being that the holes had not been taped with a bottom tap and thus the bolts were binding on the tapered thread, I called beneteau and discussed the problem upon which they asked me what they could do for me, I responded by asking them to send me a 30 mm bottom tap so I could re-tap the 3 affected holes,
in response to that they sent me a Link to a web site that had a 30 mm bottom tap for sale, :cussing:
I ordered the tap at a cost of around $76 total and was able re-tap the holes so the would take the 30 x 120 mm bolts this has given me "peace of mind" on the keel to hull connection
But I was also amazed at the 2 holes just forward of the sump, when I removed them I found a huge amount of sealant under the two washers the reason being that the top of the hole was not flat, when the new bolt and washer are screwed in the washer touches one side but where the fiberglass slopes down to the sump I found a 14 mm gap ( Looking sideway at it I could see the treads of the bolt ) less than half the washer was in contact with the hull, the only thing to do is to build up this area with fiberglass and resin till it becomes a flat area for the washers to sit flat on, the total result of this has given me a lot of questions as to the quality control of the building of the boat on such a important connection point why was this not seen before it left the factory NO quality conrol ?????
"why use double washer" only 1 reason, the bolt would not go into the hole far enough and the angle of the hull at the 2 holes forward of the keel astound me
any one else have double washers ?? its worth checking
on but found that the bolts became tight when they hardly entered the holes which had had two washers on, the reason being that the holes had not been taped with a bottom tap and thus the bolts were binding on the tapered thread, I called beneteau and discussed the problem upon which they asked me what they could do for me, I responded by asking them to send me a 30 mm bottom tap so I could re-tap the 3 affected holes,
in response to that they sent me a Link to a web site that had a 30 mm bottom tap for sale, :cussing:
I ordered the tap at a cost of around $76 total and was able re-tap the holes so the would take the 30 x 120 mm bolts this has given me "peace of mind" on the keel to hull connection
But I was also amazed at the 2 holes just forward of the sump, when I removed them I found a huge amount of sealant under the two washers the reason being that the top of the hole was not flat, when the new bolt and washer are screwed in the washer touches one side but where the fiberglass slopes down to the sump I found a 14 mm gap ( Looking sideway at it I could see the treads of the bolt ) less than half the washer was in contact with the hull, the only thing to do is to build up this area with fiberglass and resin till it becomes a flat area for the washers to sit flat on, the total result of this has given me a lot of questions as to the quality control of the building of the boat on such a important connection point why was this not seen before it left the factory NO quality conrol ?????
"why use double washer" only 1 reason, the bolt would not go into the hole far enough and the angle of the hull at the 2 holes forward of the keel astound me
any one else have double washers ?? its worth checking