Good Day All. I am new to this forum, own a 2004 Hunter 326, and have always wondered about re-torqueing keel bolts. Have any of you done this? is it recommended? If done, where did you find info on the torque values? Thanks in advance.
Re-Torqueing keel bolts.
- Thread starter AndrewM
- Start date
I doubt that you would have to re-torque but if you want to check I have attached a standard torque reference chart. How long have you had the 326? Did you get it from Port Credit? I had a buddy with an 04 326. Have not seen many, just wondering if it was the same one.
Hey, thanks for the quick response, I was only asking as I grounded last year and am worried about impact maybe having loosened the bolts/nuts slightly and if a retorque was a good idea. I have owned the boat since last June, bought and picked up in T.O.
Welcome to the SBO forum by the way. Hard to tell on the other end of the internet but if it were me I would probably check the torque. I would be concerned if they were found loose as it would indicate a possible over stress. I assume that the boat is out of the water. Is there any signs of trauma at the keel joint? You may want to consider getting a professional to look at it. It will depend on the severity of the grounding. I do know that Hunter crashes the first built model of each boat into the beach at full speed to test the structure of the keel hull joint. Its a sand surface but it is a dramatic sudden stop.
Lake Ontario is a deep lake, except where it's not.
Where do you sail out of?
Lake Ontario is a deep lake, except where it's not.
Where do you sail out of?Hey, thanks for the welcome. There were no signs of trauma when I checked after the boat was lifted; no cracks or signs of loss of integrity of the joint, in fact there was little-to-no gouges or scrapes in the keel itself, all told I think I came through relatively unscathed, but still have a few lingering doubts. I sail out of Brighton on Presqu'ile Bay, the grounding happened in the Bay of Quinte.
If you decide to retorque - consider that most torque charts are for clean and lubricated threads. So the conservative method would be to remove the bolt, clean and lube the threads and then re-install. As to damage from a grounding - there are three areas of potential damage:
Damage to the female threads in the keel, damage under the blot head in the keel support structures, and lastly (most unlikely) damage to the bolt itself. Damage under the bolt head from the impact should be evident if its there. Damage to the female keel threads would not likely be directly viewable but clues such as partial thread material stuck to the bolt threads as you remove the bolt might provide some clues- again , in this case you would expect to see space under the bolt head/washer.
Good luck
Damage to the female threads in the keel, damage under the blot head in the keel support structures, and lastly (most unlikely) damage to the bolt itself. Damage under the bolt head from the impact should be evident if its there. Damage to the female keel threads would not likely be directly viewable but clues such as partial thread material stuck to the bolt threads as you remove the bolt might provide some clues- again , in this case you would expect to see space under the bolt head/washer.
Good luck
Thank you for that insight. I did look closely around and under the bolt heads/washers; no cracks, no signs of shift/increased space under the bolt heads/washers, no water intrusion, certainly looks like I got off lucky.
Clean threads, yes. Lubricated threads, no. Standard torque charts are for clean and dry threads. Lubrication lowers the friction coefficient between the threads and will increase the resulting torque.
Was it a soft grounding or hard, i.e. mud or rock, and was it full stop or slow motion. The keel to hull joint is fairly strong and unlikely the keel bolts would be affected. I would be concerned about damage to the hull fore and aft of the keel. It will flex in a hard grounding and separate the layers. It might be a good idea to have a surveyor have a look at the hull itself and the keel joint.
RoyS highlights the difference in torque charts lubed vs dry- just take the time to understand the chart basis
Dry bolt torque is approximately 30% higher - or 628 lbf ft. If the bolt is lubricated with SAE 30 oil - the torque compared to a dry bolt is reduced with approximately 40%. Note that if torque specified for a dry or slightly oiled bolt torque is applied to a lubricated bolt - the bolt may overload and break.
Dry bolt torque is approximately 30% higher - or 628 lbf ft. If the bolt is lubricated with SAE 30 oil - the torque compared to a dry bolt is reduced with approximately 40%. Note that if torque specified for a dry or slightly oiled bolt torque is applied to a lubricated bolt - the bolt may overload and break.
Do you have a source for this information ?
Hunter keels are lead, and all keel bolts for lead keels (really studs) have the lead cast around the bolts. The bottom of the SS keel bolts are either bent in the shape of a large "J" or bent at 90 deg. Lead does not take kindly to threads of any kind.
I think you'll find as many theories about re-torqueing keel bolts as there are different keels.
I was forced into having a 20 year survey in 2019 by my insurance company. I contacted one of their recommended surveyors and wound up with a very experienced and well certified individual. One of the things he required was checking the torque of all of the keel bolts. I could be responsible for supplying the torque wrench and heads or he could supply a subcontractor who would do it for time and materials ($$$$) but it was required. He only wanted to see a torque of at least the torques shown on his sheet to order to pass. His sheet was within a few LB-FT of the numbers supplied by by Hunter. If I over-torqued it, that was my problem. An interesting learning experience so I supplied the wrench and welded up the required heads:
Other surveyors will have different approaches.