Madness or "do able" ? MD2B engine swap whilst afloat

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zambant

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May need to remove my MD2B engine from my Centaur.

Trying to eliminate the cost of cranage out.

I have a PSS stern seal and my mate says we would be mad to do it on the
water as its only the engine that will stop the prop shaft from moving up and losing the seal on the PSS - resulting in the boat sinking.......

I think we can clamp the propshaft to stop it moving befor disconnecting the drive flange

I really could do with not having to spend the £250 to get the boat out
and back in the water.

I may need to swap the engine out as its really poorly.....investigations
still ongoing..

Probably use a quayside hand crane to do the lifting

Anyone done it please?

Any advice / ideas / suggestions most welcome.....

Thanks

John
 
I know someone who replaced their engine and stern gear without craning out- they dried out against a wall for crucial stages of the job.
You might be able to use your boom and mainsheet as a makeshift crane to save a bit more money.

With a Centaur, I would have thought the best option was to find a good beaching spot somewhere and do the job there. Maybe neap the boat to get more working time.
 
I'm not saying it's impossible, but there are a lot of 'what ifs' that may only rear their heads once you commit to the job on the water. By then, it might be too late! It's a big weight to shift and you kind of want the boat steady so you can concentrate on steering the engine out while being in full control of the movement.

Just suppose you go to replace the engine, and you find that the mounts need to be remade and the parts aren't immediate available? You will also be subject to the vagaries of tide and wind, just when your crane guy is available, if the Law of Sod reigns, as it normally does.

I would go for the lift. I know that £250 is an extra, but spread that over the 20-30 years that your replacement engine will last, and it becomes pretty good value.:rolleyes:
 
I took my MD2B out of SR while still afloat.

To be fair it was in a tidal dock where she settled in deep mud at LW, but that could have made the problems worse if the prop had been pulled out by the mud as we "dried" & lifted. IIRC, I simply tied off the shaft so it couldn't drop out - jubille clips? - then the situation is no different to floating normally. I put the engine in the back of my car using a derrick on the "houseboat" coaster I was alongside & took it home. It took 3 days to get hold of an engine hoist to get it out of the back of the car (Citroen Ami6) & another couple of months to complete the rebuild.

SR never took on any undue water & I don't even remember being that stressed about the situation.

Be warned it is a VERY heavy engine & removal of Flywheel & gearbox will help you manhandle it. I left mine intact as I had access to the derrick &, eventually, the engine hoist (which only just coped with the whole lump).

EDIT:
Removal: Lift it forward into the saloon first, supporting with ropes from beam across cockpit & main hatch. You can use the boom provided you use a halliard to support the boom at (or at least near) the point where the engine load is applied.

Once lifted, slip planks underneath & slide into saloon. Then refasten to lift thro main hatch & into cockpit using boom. All you need then is some way of lifting onto quayside & into car. The close quarters manouvering is all done on the boat using lifting gear on the boat, so no problem there. Lifting out of cockpit is relatively snag free so boat movement (within reason) is not an issue. Ideally you need some sort of dockside crane or gantry, but you could lash something up as a derrik if necessary.

While heavy, if you strip off the flywheel & g-box in situ it is probably a reasonable 2 man lift.
 
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Thing to watch with the PSS is not to let the shaft move forward. It won't be a problem when the engine is fully disconnected as the bellows is clamped to the shaft and the weight of the prop and shaft will keep the bellows compressed. When the engine is out might be a good idea to wedge the shaft - leave the coupling on - so there is no chance of the shaft moving forward. Take care when you disconnect the flange that you keep the whole thing straight as you move the engine forwards. Best if possible to remove the bolts completely, but remember there is a register of about 5mm on the flange face.
 
Dad use to change engines afloat, but that was stuart turners so a lot lighter. I have an MD2B in a shed at work and have yet to get it home: too heavy. But do not see any reason why not do the job afloat, especially if a pier crane/derek is available to do the lifting. My only conern with lifting would be to quadrauple check the security of the lift as I would expect it to go straight through the bottom of the boat, literally, if a strop breaks!

Good luck with it.
 
I disconnected a propellor shaft coupling from a gear box to free the propellor from a tightly bound rope while afloat. The propellor shaft dropped back with quite some force (the yacht had a skeg which prevented the propellor shaft from fully dropping out). I could haul it back again at the end of the job but it took a bit of effort.

This movement is beneficial but I would not want to rely on it. As others have said clamping the shaft in place is a good idea as it would also prevent the shaft from riding forward, which you don't want!
 
stav said:
Dad use to change engines afloat, but that was stuart turners so a lot lighter. I have an MD2B in a shed at work and have yet to get it home: too heavy. But do not see any reason why not do the job afloat, especially if a pier crane/derek is available to do the lifting. My only conern with lifting would be to quadrauple check the security of the lift as I would expect it to go straight through the bottom of the boat, literally, if a strop breaks!

Good luck with it.
Click to expand...

Split the flywheel, G-box & ancillaries off, you then have a 2 man lift (engine) a heavy 1 man (flywheel) & a heavy box of gerabox & bits. The car will carry it if you can get it between the axles (hatchback, van or pick-up).
 
I removed a md11c (250kg) using the boom and halyards I was scrapping the engine so I stripped all the major parts off including exhaust manifold,altenator,starter etc.(the flywheel is really heavy) doing this considerably reduced the overall weight.I used jubilee clips to secure the prop shaft.The new engine was 80kg lighter.
 
Searush said:
Split the flywheel, G-box & ancillaries off, you then have a 2 man lift (engine) a heavy 1 man (flywheel) & a heavy box of gerabox & bits. The car will carry it if you can get it between the axles (hatchback, van or pick-up).
Click to expand...

Great idea, why have I been looking at the 'lump' in the shed, thinking I must move this....The obvious is so blinding sometimes........Dooooohhhhhh.
 
I had my MD2B out of the boat for a tidy up a couple of years ago. That was winched out with the boat still in the water. I have convention seals, and the part of the coupling attached to the propellor shaft would have stopped it coming right out had it had the inclination to move.
 
I would advise against it, because of the PSS.

Last winter, while ashore, I disconnected the prop shaft and lifted the engine a couple of inches in order to replace two engine feet. Then reconnected and aligned engine to prop shaft, also tensioned the PSS bellows the correct amount.
At lift in, there was quite a leak from between the sealing faces of the PSS. This disappeared only after a couple of minutes of engine running in gear.

So my conclusion would be that you should not "disturbe" the PSS while in the water if you are not able to run the engine pretty soon.
 
If for instance you were moored against the scrubbing piles at Warsash on the Hamble and could arrange for a lorry with a crane attachment to lift it bodily from the boat. One of those trucks say from Elliotts that do the gravel bags could park alongside the boat.
There is a charge made by the Harbourmaster after 48hrs, so a tow across to the visitor pontoons would be needed; (if much longer period needed ask the Harbourmasters office), but if all kit available should do it OK.
When I first lifted my old MD1B from my Tiger I did as Searush described but used a doubled 4 by 2 across the hatchway and a pulley system from Halfords, about 8:1 I think, with a small jammer fitted, later lifted by the club crane(no longer existing) to the trailer for taking home. I removed only the dynastart for access,flywheel left on. There may be two lifting lugs on the top of the engine rather than a sling so that a higher lift can be made.

ianat182
 
zambant said:
Any advice / ideas / suggestions most welcome.....
Click to expand...

Almost anything is possible with careful planning and forethought. If the shaft is the problem than there has to be some way of stopping it moving forward - something to do with jubilee clips and ropes maybe?

Craning the engine out with a shore side crane should be easy enough. I've done it with manual power a few times albeit with lighter engines from Yanmar.

The bit that appalls me is the idea of £250 for a lift out and re-launch. You need to do something about your sailing costs. It should be well less than £100 - its only just that for my 35 footer! Join a club or if necessary, join another club
 
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