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Help - Stuffing Box Plate - broken bolt
Posted: Sat Jun 19, 2010 8:16 am
by mpulsev10
So i launched boat yesterday, but have a leak around where the prop shaft goes through the hull. There is the Stuffing Box then a Triangle shaped plate with three bolts that go through the hull. The bottom 2 bolts where completely loose but tightened up just fine. the upper bolt is broken off and water is trickling through. It is currently in the water and i dont want to take it back out unless i have too. I swam under the boat and felt around a bit. From what i could tell it seems to have a triangle plate on the outside as well that has threaded holes and i can feel the bolts sticking out. If that is the case, my plan is to drill from the inside of the boat. I was going to bore the Hole and threaded plate completely out, then swim under the boat and put a 2" stainless 5/16"s bolt back through from the outside in with some boat life caulk (water cures) and a lock washer and nut on the inside. I was just curious if this is my best choice or if there are other options ? Any help would be greatly appreciated.
Boat is a 79 F36 convertible with twin 454s.
Also the same prop shaft was not tight and came loose from the front couple that mounts to the transmission coupler. I think the vibration is what may have caused my problem. I was able to put the coupler back on, it had a Key that was 3" long and way to big, i cut down to 1" and cleaned it all up and it went back together fine.
thanks,
Charlie
Posted: Sat Jun 19, 2010 10:59 am
by captainmaniac
If the coupler let go and you have stuffing box damage, I would be wondering what other damage you have that you can't see... You may have an underlying problem (out of balance prop, bent shat, loose strut, alignment issues) that caused all this, and if you just patch things back together again you could easily end up back where you started once you have gone for a run or two - or worse, something bad happens while you are out on your next run.
I am never a fan of drilling below the waterline while the boat is floating. I would pull it to do this repair (and have everything else checked out at the same time).
If you insist on doing it in the water, it needs to be a 2 person job, and you will want scuba tanks (or air supply) because you will be under there for a few minutes putting the bolt in and getting it tightened. If / when you drill the hole out, have a bung ready - a tapered wood dowel that will fit the hole. If things get out of hand, you realize the bolt won't fit, or you drop it..... you can shove or pound the bung into the hole to plug the leak (hopefully long enough) for you to get the boat hauled... Maybe you drill the hole and put the bung in, have your helper watch the bung while you go below, helper pulls bung and you pop bolt in, then you work together to tighten.
But again, if it was me, the boat would be out of the water for this.
Posted: Sat Jun 19, 2010 5:38 pm
by prowlersfish
The bolts come thru from the out side (you tightened up nuts on the other 2 bolts ) ? If I am correct on this you should be able to take a punch and knock it out , It should be a carriage bolt . A bronze bolt would be the best bet.
This should be done out of the water It will be hell trying put and hold the bolt in place under water .( and it will need sealer )
Posted: Sat Jun 19, 2010 6:48 pm
by k9th
I agree with Paul - I would not attempt any repairs of that nature while in the water - very risky and too much can go wrong with very dire consequences.
Posted: Sat Jun 19, 2010 7:48 pm
by Big D
Not what you want to hear, but personally, I'd be pulling her out of the water like the others suggested. Things seldomly go as expected and rarely end up being the five minute job you planned for.
You also mentioned that the two bottom bolts were loose as well. At this point, I'd question the integrity of the seal around the whole thing.
So this is what I would do:
While in the water, I'd separate the coupler, and check that the alignment is not out more than .003. If it is, take note of how much.
Haul the boat out. With the coupler up against the tranny flange, check the alignment of the shaft as it goes throught the strut bearing. If it looks good and the bearing is in good shape, and you noted the alignment was off earlier, then it shouldn't be too difficult to correct on the engine side. If it's way off at the strut, it's a bigger issue that you will need to address.
Next I'd remove the two bolts you tightened and if it is a separate stern tube plate, then remove it as well and rebed it again. Then caulk and install the three bolts, get bronze as mentioned.
May sound like over-kill but you shouldn't have to revisit the issue again if done right the first time.
Posted: Sun Jun 20, 2010 7:12 am
by Danny Bailey
Do not put a stainless steel bolt in a bronze stuffing box. Electrolysis will eat the head off of it. Use a marine (not hardware store) bronze bolt. Replace all three...the other two are most likely close to failure. In water no problem but you need a tank to be able to stay down long enough for someone inside to put on washer and nut and snug it up. Do not remove more than one bolt at a time. If you remove all three stuffing box will slide forward on shaft and boat will sink real fast!!! Like Prowler said the bolt will pop right out with a tap from a hammer and pin punch. Carriage bolt will hold itself for tightening after snug. Check other side also. If bolts have a copper color, replace them also. After replacing bolts check shaft / coupling alignment.
Posted: Sun Jun 20, 2010 8:59 pm
by mpulsev10
Dang, thanks for all the help, man i wish i would have seen your post before tonight danny. I fixed it saturday afternoon/evening. Wonderfull "5 minute job" heh. Seriously, we started drilling and the bolt fell right out, i put some marine sealant on my bolt, took about 4 times going under to get it in (without air tank) But got it, put nut on, it was snugged up easily from inside without a wrench on outside. Done deal.
Unfortunately - I used a stainless steel bolt, so with the electrolisys issue i guess i will be going for another swim in the near future

But all in all, it sealed right up. Took it for a one hour cruise. Then spent all day on it today. It runs great, no crazy vibrations and the bolts are still tight. Boat is running great !!
thanks guys.
Posted: Sun Jun 20, 2010 11:37 pm
by alexander38
now that you got your feet wet

you really need to replace that s/s bolt asap..

Posted: Mon Jun 21, 2010 7:36 am
by Danny Bailey
Chances are that SS bolt will last until next haulout unless you have a really messed up electrical / bonding system. Worst case scenario you wind up with a 5/16 diameter hole in the bottom. Maybe monitor it until next haulout??
Posted: Mon Jun 21, 2010 7:58 am
by prowlersfish
Don't panic I bet it will last years , you put a bronze props on your stainless shafts ? they make bronze rudders with stainless shafts right ? But I would still replace all 3 bolts with marine bronze next haul out
went through this out of the water myself
Posted: Mon Jun 21, 2010 8:17 am
by BobCT
3 of the 6 bolts were broken and the studs came out the same way, when I started to drill them out. The shaft log inside the boat looked terrible but cleaned up just fine.
You want Silicon bronze bolts, I know Jamestown Distr has them. The shaft log and stuffing box are probably made by Buck Algonquin at least they made them for Trojan in '88 along with the rudder/tiller and connecting arm.
I agree, I wouldn't worry about the SS bolt until you get hauled.... it'll be fine but your bonding system does need to be 100%.
Bob