stern tube glassed in at almost max angle

vyv_cox said:
Maybe 30boat is a lot more capable than I am!
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Not at all.I cut and shaped a piece of marine plywood and then sheathed it with
epoxy/glass and sanded it flat.It was then attached to the Aquadrive which had been fitted to the shaft and gearbox.Wedges were used to support the shaft.With everything nicely lined up I lightly glassed the whole thing to the hull.This ensured alignment in one go.Once the epoxy cured I reinforced the glassing and that was it.
 
Your putting a £4000 new engine into a £4000 boat, dont bodge it cut out the tube and get it right you will sleep better at night knowing the job is 100%.

Are you sure the bearers are strong enough? I would make a ply wood frame and glass it in then bolt angle iron to it and sit the engine on these. The 1GM moves around a lot when not on load.
A cutlass bearing needs to have a water flow through it to remain cool and lubricated, fitting one at the top of the tube is not a good idea as it may overheat.
 
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I went to give David a hand this morning to 'try out' the engine on the beds as they are, and took a few photos which are attached below.

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I am wondering if perhaps the stern tube shifted sideways slightly as well when it was being glassed in, as the starboard mounts are off the beds when the engine is roughly in line (longitudinally) with the shaft (just sighting by eye).
Current plan is to extend the fibreglass angle section forward beds by another 2" further forward, and to sit the forward mounts on a couple of rectangular steel plates (a bit larger than the mount bases) before through-bolting them to the GRP angle.

The starboard aft bed will have to be made wider on the inboard side, as the mount is half off it already at the moment. David will make up a pair of improvised Bighead type fastener plates (ie a plate already pre-drilled with two holes to suit M10 bolts which will be inserted from underneath and welded to the plate) and these will be bedded in securely on the aft beds and over-laminated once the final alignment has been established.

It is possible to cut a couple of inches off the stern tube, although the Volvo shaft seal will then be quite a tight fit.
This, combined with moving the engine forward by 2", should allow enough room (and a bit extra hopefully!) for installing an Aquadrive (as shown in the rough 2-D cardboard cut-out hanging on the prop shaft).
The seacock and through-hull fitting for the cooling water intake will be fitted on the side of the keel sump forward of the engine.

The exhaust muffler is shown sitting on the stern tube - there does not appear to be anywhere else where it can be fitted, and this is the lowest place it can be. The 'drop' from the exhaust elbow seems to be reasonable, although the elbow is pretty much at or just below the static waterline, hence it will definitely need to have an anti-syphon valve fitted.
 
You really could do with a shaft and coupling in place to align the engine and beds, even a few thou gap between the faces will need the engine front end shifting a remarkable amount. As others suggest, get the drive train in place, then align the engine, then make the beds up to it. The other way is to bring a string up through the tube centre and through the engine bay, use two ply templates which are the profile of the engine feet and holes for the shaft centre line looking from 'end on'. The installation paperwork should have this drawing.

If you don't change the tube, and the angle is really at the limit, it may be possible to remove the sump and slightly modify the oil pickup to be where the oil is deepest. Mind you, new engine with guarantee............
 
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Bajansailor said:
I am wondering if perhaps the stern tube shifted sideways slightly as well when it was being glassed in, as the starboard mounts are off the beds when the engine is roughly in line (longitudinally) with the shaft (just sighting by eye).
Current plan is to extend the fibreglass angle section forward beds by another 2" further forward, and to sit the forward mounts on a couple of rectangular steel plates (a bit larger than the mount bases) before through-bolting them to the GRP angle.

The starboard aft bed will have to be made wider on the inboard side, as the mount is half off it already at the moment. David will make up a pair of improvised Bighead type fastener plates (ie a plate already pre-drilled with two holes to suit M10 bolts which will be inserted from underneath and welded to the plate) and these will be bedded in securely on the aft beds and over-laminated once the final alignment has been established.

It is possible to cut a couple of inches off the stern tube, although the Volvo shaft seal will then be quite a tight fit.
This, combined with moving the engine forward by 2", should allow enough room (and a bit extra hopefully!) for installing an Aquadrive (as shown in the rough 2-D cardboard cut-out hanging on the prop shaft).
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Sorry to say it but it is beginning to look like another bodge to correct the original one. If the stern tube was positioned correctly the engine would presumably sit on the intended beds, although these look rather flimsy to me, the seal would fit fine and we wouldn't even be talking about an Aquadrive. Raising the engine and sitting it on those spindly, flexible mounts can't be good for long term reliability. Cut the tube out, set the engine as low as possible on wooden or metal beds with the shaft and coupling in line and you have some hope of success, without resorting to expensive means of overcoming the initial fault.
 
I am inclined to agree with Vyv, sounds like the errors are multiplying. While cutting out the shaft will be messy, I would be much happier with the end result. Cheaper too.
A
 
vyv_cox said:
Sorry to say it but it is beginning to look like another bodge to correct the original one....
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I'm sorry, but I have to agree with Vyv. At the risk of labouring the point - cut out the tube and start again. I bet you could get it out intact in a couple of hours.

Best of luck, whatever :)

Andy
 
I believe the Aquadrive will easily take that angle,that's one of the things they're meant for.I would only resort to cutting the tube out if the Aquadrive couldn't correct things.Why not contact Halyard marine and discuss this with them? The pics are self explanatory.
 
TNX for all of your opinions posted above in response to the last set of photos I posted - the consensus is pretty obvious!
I shall phone David and suggest that he log on and have a look, and see what he says.
Vyv, re the engine mounts, they are very (too?) flexible - do you think they should be stiffer or more substantial?
 
My opinion is that you are now in danger of continuously looking for cures to arising problems which are all caused by the same thing – the stern tube. That’s not to say it is impossible to make a good job of fitting the engine, just that is likely to be hard work and time consuming.

As for the engine mountings, again it’s only my opinion but I suspect that if the front ones are not beefed up with additional support they will over time delaminate due to movement and vibration.

The issue with glassing in stern tubes is that the GRP shrinks as it cures and the hotter the mix the more the shrinkage. The fact that most of the glass is placed above the tube means that it will lift as it cures. I would suggest that if you do remove and refit the stern tube that it is lightly glassed in place, left for 24 hours and then checked before finishing the job.

I have to agree with the other posters who suggest fitting everything in place first and then sorting out what needs doing / manufacturing.

Whatever you decide to do I hope it goes well.
 
Bajansailor said:
TNX for all of your opinions posted above in response to the last set of photos I posted - the consensus is pretty obvious!
I shall phone David and suggest that he log on and have a look, and see what he says.
Vyv, re the engine mounts, they are very (too?) flexible - do you think they should be stiffer or more substantial?
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Those are the standard Yanmar mounts, in use in 000s of installations. They are quite flexible, deliberately so, in order to reduce transmission of engine movement to the hull. As a single-cylinder engine with a light flywheel it does move about quite a lot esp on tickover. I have an engine exactly like that in an old wooden boat and there is little or no movement at the shaft; the mounts seem to absorb energy and ensure that any movement of the engine is pretty much around the shaft axis, so not much stress on shaft, couplings and shaft seals as a result.
 
KenMcCulloch said:
Those are the standard Yanmar mounts, in use in 000s of installations. They are quite flexible, deliberately so, in order to reduce transmission of engine movement to the hull. As a single-cylinder engine with a light flywheel it does move about quite a lot esp on tickover. I have an engine exactly like that in an old wooden boat and there is little or no movement at the shaft; the mounts seem to absorb energy and ensure that any movement of the engine is pretty much around the shaft axis, so not much stress on shaft, couplings and shaft seals as a result.
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I think we are at cross purposes. I am not referring to the rubber mountings on the engine but the grp boxes shown in the photos. My engine is mounted on steel blocks that run the whole length of the engine bay, they are about 1 x 3 x 30 inches, bolted firmly to structural members of the hull.

At the very least I suggest that some fairly substantial timber beds should be shaped, bolted and epoxied to the hull of the boat, although a fabricated tubular steel arrangement would be good also. Don't forget that the engine is a very heavy lump subjected to large accelerations in a seaway. It needs to be well attached to something solid or it could break away.
 
Sorry but having seen the photos and read the posts I dont think that there is any part of the existing work that is satisfactory. Leaving the tube in place will inevitably put the engine in the wrong place. I doubt you can get the glass tube out intact once glassed in. The only answer is to rip the lot out. Build substantial beds in the right place. Dry fit the engine, shaft and tube getting the alignment correct. Then glass in the new tube slowly so it does not get pulled as the resin sets. Unless the shaft is too long for its diameter there is no need for a cutless bearing on the inboard end. If you have to do this it must have its own forced water feed, which can be achieved by using some of the face type seals. It is best avoided.
 
vyv_cox said:
I think we are at cross purposes. I am not referring to the rubber mountings on the engine but the grp boxes shown in the photos.
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Yes I agree, the beds look a bit flimsy. I was taken in by the use of the word 'mounts', and thought you were referring to the err... engine mounts I think they are usually called. Not like you, Vyv ;)
 
Thank you everybody for all of your very useful contributions and opinions and advice posted above.
I shall report back later on (not too sure when!) with an update once David has decided which plan he is going to follow.
 
There is a way to avoid all that GRP round the tube. Make a small bulkhead with a hole for the tube at the inboard end, GRP overall, GRP the outboard end outside. Now fill the space round the tube behind the bulkhead with sand, put a thin ply lid on it and GRP over. Now the tube is held by the sand, but you can get the tube out if you want, in case of damage, which can happen in extreme circumstances.
 
stern tube

err...just a thought but if is a new engine and not been fitted yet why not contact the dealer and inquire about swapping the gear box for a down angle one ? might not be as expensive as you think especially if its an exchange.
regards rachel
 
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