Lost propellor, Volvo saildrive

[inspectr]

Approaching the mooring in strong winds, too much momentum, we overshot the mooring buoy, skipper misses the buoy . Helm, (wife who has done this a 100 times) hits reverse hard.; Nothing, the engine revs up but nothing happens. We emergency drop the anchor narrowly missing our neighbouring boats and consider options. Call the marina and our tender guys race out to help. They tow us onto the mooring and help us secure the boat.
Once I have sent the crew and passengers ashore, I dive over the side to find that the prop is missing! No Volvo cone nut, no retaining screw, just a bare shaft???
The boat had been out of the water in October, 3 months previously and the yard, replacing the rudder bearings advised that the saildrive boot was missing and needed to be replaced. The boat has only been used three times since October. I am not convinced that the yard replaced the prop properly, but no way that that can be proved?
A few days later our divers found the propellor in mud and ooze some 20 metres away from where we expected the prop to land. There was a very minor ding on one of the two blades. Fantastic work by the dive guys BTW
We found no damage to the mooring lines
When we got the prop out of the water we discovered that the rubber bushing was missing? Volvo aluminium 16" prop BTW
The two bladed prop has been on the boat for more than 10 years and seems to be perfect for this boat - Dufour 35 Classic, 18HP Volvo MD 2020, 2800 RPM, 6 - 7 knots when the hull is clean
Prop has been sent off to QLD for rebushing and minor repairs and we have it back ready to reinstall, with a new Volvo cone nut and screw fitting kit, hopefully in the water. Great service from the prop guys BTW
I have some questions
Do we get the divers to use Loktite ( and if so what type) on the cone washer and retaining screw
Some recommend that we use plumbers tape on the cone washer and retaining screw rather than Loktite
Loktite instructions are not that clear about use in under water installations
The other question is whether the 16" two bladed prop would be better than the 12" three blader that we have as a spare
We also have a 16" 3 bladed folding prop as a spare, but that needs to be installed when the boat is out of the water. We took that off when we bought the boat as it occasionally refused to go into reverse, but we discovered that the yard had used the wrong anode on the back which fouled the blades as they reversed

[skipperpete]

Did your propeller get fouled by the mooring line as you overshot the pickup?
If not , it's hard to connect the fact that the propeller just fell off in astern leaving a bare shaft and the fact that the propeller was later recovered.... but without the press fit rubber bushing complete with splined hub. These are two different failure scenarios.
Good work finding the propeller. The aluminium alloy cone nuts often have helicoils inside and loctite might bond to the coils and pull them out next time you remove the propeller so consider that before using loctite.

[inspectr]

We have assumed that the mooring line caught the prop, but you would assume that there would be at least SOME visible damage on the rope.
We could see none?
There was a small chip off one of the blades of the prop, now fixed
Prop repair guys have fitted a metal splined hub rather than the original rubber bushing
What puzzles us is that we had anchored earlier in the day and hit reverse a bit to dig in the anchor. We had then run back to the mooring as normal, wind astern, following seas, no issues!
We lost the securing screw, the Volvo cone washer, and the aluminium two bladed prop. The rubber bushing was not found. There is a stainless steel collar that fits over the shaft, that was found on the shaft by the divers and we have cleaned and saved it.
The securing bolt is lost, and the threaded hole in the saildrive shaft is clean and OK. We have not sheared the securing bolt obviously
The cone washer is gone also
The only logical explanation that I can see is that the bolt was not secure, leading to it winding it's way loose and finally falling off, which allowed the cone washer to also wind its way off, allowing the prop to fly away when
a. restricted by a line caught on the prop?
b. an over aggressive reverse sheared the join between the rubber bush and the prop
Hard to prove and given I have a good relationship with the boatyard, one that I guess I will just have to wear. However I am sure that the "service and saildrive repair" was not done properly, and the prop was left insecure when the boat was dropped back in the water. Interestingly, the boatyard is not returning my calls???
Funnily enough the divers now have problems with THEIR engines and props and cannot return to fit the repaired prop for three weeks
We have effectively lost our summer of sailing

The question remains, should one apply Loktite or something similar to the cone washer and securing screw, or use plumber's tape as some (not on this forum) have recommended

[Boatguy30]

I have used 5200 before underwater like this on same prop and it didn't fall off from Mexico to NZ. I don't think loctite will work at all underwater

[belizesailor]

Per KiwiProps testing LocTite wont set when applied in water. Maybe there is another brand of thread locker that will?

http://www.kiwiprops.co.nz/cms/index...eneral/loctite

[kcj]

Vibra tite vc3 can be installed underwater. Must dry on surface before immersion.. 10 to 30 minute dry time..

[skipperpete]

Thanks for the clarification, I’m still puzzled by the bushing being lost.
Is the thread that the cone nut screws onto still intact or did it possibly shear off. If the mooring line wrapped tightly enough in the small gap between the prop and the leg a huge amount of pressure could be exerted there and the prop would be squeezed off...... or maybe the pressure could have pushed off the whole thing.... prop and spline bushing by breaking off the cone thread. This is the thread in the photo

[RobinScurr]

We can sympathize ... we've lost our prop on our Volvo-Penta 110S saildrive TWICE in a 5 week time period!! Everything seems fine, then lookout! Nothing when shifting, forward or reverse! Also happened when anchoring. I believe if the bolt is not properly thread locked or tight, when shifting into reverse at too high an RPM, the momentum of the bolt/cone can cause everything to loosen up. The original cone was aluminum, the replacement is a bronze center with a plastic cone attached. This may allow less momentum to loosen itself up.



We has a bao yard rplace the prop, etc the first time. It took quite a while to figure out just what parts were needed. The cone it, plastic washer and prop were easy. There is also a "ring" spacer that looks like a line cutter (but isn't) and the first time it fell off too! I believe the installer did not thread-lock or tighten everything properly (underwater) the first time. (Still haggling with them about what they should do to "make right")



I bought spare parts after the first lost prop, so had them available and dove on the prop myself the 2nd time. The diver have me a tiny bottle of "Locking Glue for Gori Propeller" I put it on both the bolt and cone threads the day before installing it. It dried overnight, but I'm not happy that I couldn't really feel the thread locker working as I installed everything. I really like the idea of caulking (like 5200, thought I think I would use 4000/4200) as a thread locker. It would be very tacky, holding even a loosened bolt in place.


Check the tightness of the cone and bolt periodically.


Lessons learned:


Check the cone and bolt periodically.
When replacing the anode, renew the thread locker.
Know the size and pitch of your propeller!
Have spare parts on board!!



For the benefit of Google searchers, here are the parts I needed on my 1981 S2 11.0a, with a Volvo Penta Saildrive 110s with a MD17C engine.


<div>850396Cone Kit, includes bolt
850888Plastic Washer832965Ring (Spacer)8506723 Blade 15 x 13 LH

[Sea Angel1]

My 3 Blade prop on a Saildrive S 130 built onto a D2-55 has now Approx. 1000 HRS. This Autominuten I took the vessel oout of the water and noticed That the prop incl Bolt and secure nut had a clearance of about 1/2“ axial. So I had luck That the prop did Not Fall off. The securing ring between securing nut and prop nut was Not properly Bent over. Also I ‚m pretty sure That the french Yard did Not put on properly loctite or Liqui Moly. Also i ‚m sure they did Not apply the correct screw Torque. (20 and 75 Nm) on the 2 different nuts. BTW Can you torque up correctly under water??

[joelhemington]

Sounds to me like you should schedule a quick haul and hang (cheaper than the total block job) once you decide exactly which direction to proceed. I doubt if this would take more than an hour to get sorted properly out of the water. I think I'd lean toward the 3M 4200 product as it can be later removed (if you have to), the 5200 product is extremely difficult to get loose.

[Akapeterc]

My mate started his cat and went to leave the marina when after a bit of noise both his propellers had fallen off. The bolts had all corroded away. The cat a lapari 41 hadn’t left the marina for at least 9 months. Electrolysis seems to be the problem

[KimSails]

I installed a FlexoFold last year. They sent the prop "pre-applied with underwater proof thread locker and can be used installed out of or under the water". I don't think they specify what it is. It may be the same or similar material kcj mentioned above. FlexoFold does say not to try to use regular loctite underwater. So, at the very least, there does seem to be a thread locker you can apply out of the water and then install the part underwater, but you need to be sure of the material usage.