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Knocked my stern tube loose -- how screwed am I?
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Ahoy, I was installing a new cutlass bearing with a home made puller (all-thread, washers, nuts), and my wrench was not long enough to give me enough torque to get the cutlass bearing in all the way. So I decided to tighten it as much as possible and then hit the end of the rod with a hammer.? Then I could tightening another 1/2 turn or so. The idea is that because of the tension from the rod, I wouldn't have to hammer as hard. That worked fine until I dislodged the stern tube. I guess I should have just waited and got some longer wrenches? Or maybe it should not have been that hard in the first place?? So the question is -- what now? From what I can tell there is a fiberglass tube that has a 3' or so long bronze tube in it, and the cutlass goes into aft end of the bronze tube. The bronze tube is now displaced about 1/4". Though it is still in there pretty tight. I've attached photos of the current situation. So, what now? I am guessing that even if I tapped the bronze tube back into place it would leak or perhaps shift around later. On option would be to hammer it back into place, and then add some fiberglass and epoxy on the inside. But that sound sketchy. Maybe the whole thing needs to be completely removed, cleaned up, and then reinstalled with?Sikaflex 291 or 292 or something? Or maybe it only needs a little bit of sealant on the last inch of the tube? I'm trying to get an idea of the scope of the project and then decide if I should do it or get the boatyard to do it.? From what I can tell, stern tubes do have to be replaced now and then and are (often) not permanently affixed to the boat. And, perhaps if mine came loose 'this easily' it was time to reseal it anyway? I'd like to pretend that I accidentally discovered some maintenance that needed to be done anyway, though I suspect that is not the case. Worst case, I guess I'll just have to glass over the hole, take out the engine, and get a big sculling oar like the guy on How To Sail Oceans.? Thanks! - jeremy |
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For some reason the attachments didn't make it through, here is a link instead, - jeremy ---In T27Owners@..., <jeremy@...> wrote : Ahoy, I was installing a new cutlass bearing with a home made puller (all-thread, washers, nuts), and my wrench was not long enough to give me enough torque to get the cutlass bearing in all the way. So I decided to tighten it as much as possible and then hit the end of the rod with a hammer.? Then I could tightening another 1/2 turn or so. The idea is that because of the tension from the rod, I wouldn't have to hammer as hard. That worked fine until I dislodged the stern tube. I guess I should have just waited and got some longer wrenches? Or maybe it should not have been that hard in the first place?? So the question is -- what now? From what I can tell there is a fiberglass tube that has a 3' or so long bronze tube in it, and the cutlass goes into aft end of the bronze tube. The bronze tube is now displaced about 1/4". Though it is still in there pretty tight. I've attached photos of the current situation. So, what now? I am guessing that even if I tapped the bronze tube back into place it would leak or perhaps shift around later. On option would be to hammer it back into place, and then add some fiberglass and epoxy on the inside. But that sound sketchy. Maybe the whole thing needs to be completely removed, cleaned up, and then reinstalled with?Sikaflex 291 or 292 or something? Or maybe it only needs a little bit of sealant on the last inch of the tube? I'm trying to get an idea of the scope of the project and then decide if I should do it or get the boatyard to do it.? From what I can tell, stern tubes do have to be replaced now and then and are (often) not permanently affixed to the boat. And, perhaps if mine came loose 'this easily' it was time to reseal it anyway? I'd like to pretend that I accidentally discovered some maintenance that needed to be done anyway, though I suspect that is not the case. Worst case, I guess I'll just have to glass over the hole, take out the engine, and get a big sculling oar like the guy on How To Sail Oceans.? Thanks! - jeremy |
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I just want to clarify and add one more thing. In the title I said I knocked the bronze tube loose. But that is an overstatement. It definitely move 1/4" or so -- but if I grab it and try to move it, it does not wiggle or move in or out at all. So it is still in there pretty darn tight. I also added a photo to the album of the tube inside the boat. The fiberglass around the tube there used to actually be laminated to the tube, but has delaminated. Perhaps friction is primarily what holds the tube in place and the little bit of fiberglass on the inside prevents water that makes it around the outside of the tube from leaking into the bilge? Updated album:? - jeremy On Sat, Aug 24, 2019 at 6:17 PM Jeremy Shaw <jeremy@...> wrote:
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Hello Jeremy,
Since it came loose I have to think it was a problem waiting in the wings. I would be inclined to push it out a little further, clean the surfaces,? coat with epoxy, and push it the other way, clean and epoxy, then push it back.so you can get to the set screws that? the cutlass in place. I did mine in a similar fashion, but was fortunate enough not to need a hammer. The threaded rod I used had a very fine thread for maximum force. Good luck! Fred Eagle #662 |
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If using a hammer and a block of wood you can move the tube back into position, I would clean and glass the inside with west. If the movment is very easy then sliding past and adding epoxy is ok. I would caulk the outer end with 5200. If there is, or you can create a v groove between the bronze and fiberglass that will greatly help to keep the water out.
Water trapped between the bronze and glass should not be a big issue. Bronze is awsome. If you still have concerns you could drill and tap the glass for set screws dimpled into the bronze. Alternatively you could drill small holes parallel to the bronze from the outer end in the"crack" between the glass and bronze and inject a penetrateting epoxy into the space. There is most likely a bit af salt residue in that gap already. Pre flushing with fresh water and alcohol would be advised. The full on repair would be to completely remove the tube clean surfaces and reinstall with west with structural filler. Then reglass interior end and caulk outer. The bronze was most likely set in resin originally. And for reference. It should not take quite that much force to install the cutlass bearing. Boat yards often put the cutlass in the freezer overnight and then in a cooler of dry ice prior to installing. The slight shrinkage helps install. They count on set screws to keep the bearing in place not friction. I have seen them wax a cutlass and then set in epoxy if the fit is too loose. The wax it for the next guy pulling the cutlass out. I don't think your screwed at all. Assess the fit and make a plan to the secure the tube and make water tight. There is relatively modest force on the stern tube with theese low horse power installations. With Good alignment the drag is minimal. Thrust is on the engine. Your largest concern is water geting into the bilge. |
I was told that the T27 does not have a set screw for the cutlass. I also did not notice any when i had the old cutlass out. Though, if there is one, that might explain why it is hard to get the new one in. I did freeze the cutlass, but I only have access to an ice. And it was 90¡ãF outside, so it warmed up pretty quick. In retrospect I should have perhaps done more wet sanding on the interior of the bronze tube before trying to install the cutlass, but I didn't want to remove too much material and have the cutlass too loose if there is no set screw. It is very difficult to move the stern tube pack into position, so I guess I will just do that and glass it from the inside. Alternatively, I could leave it where it is. That leaves a nice little groove around the outside of the cutlass bearing where I could install some sort of sealant. Probably not 5200 since the cutlass has to come out again at some point. - jeremy? |
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Fred, Does your boat have set screws for the cutlass? I did not encounter any that I noticed on mine and was told there aren't anyway. Though I also have an early model (#154) and you have a much later variant. So that could have changed... As for epoxying it in place -- it is still very difficult to move -- light hammering did not budge it. So even if I got it out far enough to get some epoxy on it, I am not sure I could get it back into place before the epoxy set. And it is such a tight fit, it seems like the epoxy would all get scraped off. So I am thinking that I might just hammer it back into place, and then clean up and reglass it on the inside so that if water does manage to make it all the way up the outside of the tube, it won't leak into the bilge. - jeremy
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Another update! I attached another photo and updated the albums, I am trying to figure out what sort of material is surrounding the bronze stern tube. Looking at it more closely, it seems to be thinner at the top and bottom and wider at the sides. The end that was exposed is somewhat irregular and bumpy. Using a small knife I was able to slice away some of the material and get a little shaving. The freshly exposed material underneath is gray with a hint of sparkles. On the photo, the part I cut away is around the 8 o'clock area. I am thinking that while the stern tube is inset, I should try to remove the exposed section of that material. Then I can (hopefully) move the stern tube back to its original position. There would now be a gap around the end of the stern tube that I could fill with some sikaflex 291. That would hopefully prevent water from leaking along the outside of the stern tube. I would still also treat the inside end of the stern tube with fiberglass to help hold it in place and contain any leaks that did make it that far. The stern tube is 13" long and is in there pretty tight, so I am not sure that water could leak that far. And it seems unlikely to move, even with the prop shaft spinning. But since I am already on the hard with the prop shaft out, I might as well do all the things. I'd hate to be wrong 50 miles out to sea. Any idea what the gray sparkly stuff would be ? My guess is some sort of adhesive/sealant. - jeremy On Sat, Aug 24, 2019 at 6:17 PM Jeremy Shaw <jeremy@...> wrote:
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Jeremy,
T27 hulls were laid up with polyester resin and sometimes a slurry of material that includes various cloths and may or may not include asbestos .
It looks to me that your stern tube came loose as you were press fitting a new cutlass bearing.? The good news is that the stern tube still has it's original aligment even if it moved what looks like 1/4" inside the hull.?
As for repairing this I'd suggest using Epoxy as it has the highest coeffficient of adhesion, higher than polyester resin.? I would suggest that unthickened epoxy could be persuaded to sink in a little bit from the inside of the engine compartment and that some thickened epoxy resin be used on the outside.? I'd also try to tap the stern tube back into it's original position.? One could also use a thinned epoxy resin in hopes that it would penetrate further along the stern tube.? Above all you want the stern tube to remain stationary while the shaft is spinning in it.
My best,
Caleb D
T27 #328
917 453 6846
-----Original Message-----
From: Jeremy Shaw jeremy@... [T27Owners] To: T27Owners Sent: Sun, Aug 25, 2019 12:35 pm Subject: [T27Owners] Re: Knocked my stern tube loose -- how screwed am I? Another update!
I attached another photo and updated the albums,
I am trying to figure out what sort of material is surrounding the bronze stern tube. Looking at it more closely, it seems to be thinner at the top and bottom and wider at the sides. The end that was exposed is somewhat irregular and bumpy. Using a small knife I was able to slice away some of the material and get a little shaving. The freshly exposed material underneath is gray with a hint of sparkles. On the photo, the part I cut away is around the 8 o'clock area.
I am thinking that while the stern tube is inset, I should try to remove the exposed section of that material. Then I can (hopefully) move the stern tube back to its original position. There would now be a gap around the end of the stern tube that I could fill with some sikaflex 291. That would hopefully prevent water from leaking along the outside of the stern tube.
I would still also treat the inside end of the stern tube with fiberglass to help hold it in place and contain any leaks that did make it that far. The stern tube is 13" long and is in there pretty tight, so I am not sure that water could leak that far. And it seems unlikely to move, even with the prop shaft spinning. But since I am already on the hard with the prop shaft out, I might as well do all the things. I'd hate to be wrong 50 miles out to sea.
Any idea what the gray sparkly stuff would be ? My guess is some sort of adhesive/sealant.
- jeremy
On Sat, Aug 24, 2019 at 6:17 PM Jeremy Shaw <jeremy@...> wrote:
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