Engine Installation; advice required!

[RichP]

Hi,
I'm currently putting an engine in my old Eygthene 24 quarter tonner, i have a Yanmar 1gm10 thats going to go in, as well as an aquadrive flexible coupling that i have come into possesion of, which i will be installing if at all possible to reduce vibration from the engine and stress on the transmission etc.

I have a rough idea formed in my head of how i'm going to do it, but i would like to see other peoples angles on how they would attack the problem, as i don't want to influence anyones answers, i'll state what i was going to do after a few posts have been made. (And any changes i will be making in because of the replies!)

The parts i am looking for advice with are engine positioning, hole location for the stern tube, p bracket location etc, basically the best way to get everything properly lined up or as close to it as possible to minimise wear (obviously the aquadrive will help in this).
As the boat had an engine in the distant past the engine bearers are already in place, and i have measured them as the correct witdth for the engine (pics attached), so really just tips on getting every lined up and in the right place.

Sorry it was so long winded, help greatly appreciated, thanks!

Rich

[tommays]

While the engine beds are there it does not sound like there is any shaft hole in the hull


I have spent a bit of time on Tartan 10s with the 1 cyl diesel and the output of the alternator is nice but it is really rough compared to the outboard i see on your blog

[Faster]

The angle on your engine beds seems quite steep - and looking at your hull form and the location of that heavy skeg means you'll need a steep shaft angle to drop the prop shaft through the hull before the skeg starts. Does Yanmar specify a maximum installed angle for the engine? I seem to remember they did and it may be something to check...

While I fully sympathize with the idea of getting the outboard off the transom, in this case I have to wonder if the money/effort involved in putting an engine in wouldn't be better spent on other projects. However I'm guessing that you have a problem with keeping the prop in the water as it is now.

I also wonder if using that obviously used coupling is a good idea.. Since you're doing the install from step one it seems you could build it so that that coupling is not really required - but then again one-lung diesels are always quite lumpy....

Is there an inboard-powered sistership that you can get measurements from? That's where I'd start, esp for location of the shaft log.

But honestly if you're not having problems with propulsion now, I'd think about selling the motor and getting some new sails/gear etc.....

All of which boils down to not helping you out very much.. sorry......

[GBurton]

Typically there are some people answering who do not answer the question but give dumb advice.

The way we did it was to drill the hole in the hull for the propellor shaft first.
The hole should be the same OD as your shaft log.
Next attach the shaft to the engine coupling without the flex coupling after putting the shaft through the hole....you are going to use the shaft as a "pointer"

At this point you have the engine suspended by a come along or chain block and the shaft is attached to the transmission sticking out the hole.
When the shaft is centered in the hole and the engine is at an acceptable angle, take measurements and build your "bearers" or spacers to fit to the existing bearers.

After you have the motor bolted down to your newly built bearers or bed you will insert the cutlass bearing in the stern tube or log and slide it up the end of the shaft (from the outside)
There will probably be an angle mismatch between the flange of the shaft log and the outside of the hull. Mix up some epoxy with an appropriate filler to make the mix stiff enough to hold itself up. Apply this to the area around the hole and slide the shaft log back up to press a "face" into the epoxy mix. Use some plastic on the shaft log flange so the epoxy does not stick to it.
After the epoxy dries you now have a matching face.
Drill your mounting holes for the flange of the log (through the face you just made and through the hull.

Thats essentially it.
Feel free to PM for more details

Originally Posted by RichP

Hi,
I'm currently putting an engine in my old Eygthene 24 quarter tonner, i have a Yanmar 1gm10 thats going to go in, as well as an aquadrive flexible coupling that i have come into possesion of, which i will be installing if at all possible to reduce vibration from the engine and stress on the transmission etc.

I have a rough idea formed in my head of how i'm going to do it, but i would like to see other peoples angles on how they would attack the problem, as i don't want to influence anyones answers, i'll state what i was going to do after a few posts have been made. (And any changes i will be making in because of the replies!)

The parts i am looking for advice with are engine positioning, hole location for the stern tube, p bracket location etc, basically the best way to get everything properly lined up or as close to it as possible to minimise wear (obviously the aquadrive will help in this).
As the boat had an engine in the distant past the engine bearers are already in place, and i have measured them as the correct witdth for the engine (pics attached), so really just tips on getting every lined up and in the right place.

Sorry it was so long winded, help greatly appreciated, thanks!

Rich

[Maine Sail]

The best way to start is with a laser sight. You can use ones made for rifles in a pinch but you'll need to machine a slug for it to fit in that then gets inserted into the strut. The laser is inserted in the strut and shot at the hull. It is very important that the laser fits perfectly in the strut and machining of the slug will be required. This will be your dead center mark for where the hole for the stern tube needs to be drilled in the hull. It's fairly critical that the shaft line up dead center in the stern tube when you're done as shaft whip, combined with an off center tube, can cause some nasty cyclical vibrations/harmonics and potentially wear through the stern tube..

From there on out it is fairly straight forward. I would make a jig or replica of your engines mounting points with the transmission output flange to exact scale. This will make it a lot easier to re-build the engine beds and get everything aligned before actually bringing the engine into the boat..

[sailingdog]

Part of the problem you may run into is the boat's hull may change shape slightly when it is lowered into the water... so take that into consideration when doing measurements and such.

[GBurton]

Yes - you will have to check alignment when the boat goes in the water. It should be really close, but do not rely on the flex coupling to correct misalignment. You should get it to within 1,2 or 3 thousandths of an inch without the flex coupling

Originally Posted by sailingdog

Part of the problem you may run into is the boat's hull may change shape slightly when it is lowered into the water... so take that into consideration when doing measurements and such.

[GBurton]

Just realised you don't have a flex coupling. I think the alignment is still critical though. You will have a lot of vibration even with the aquadrive if its off I believe.
Those are very nice those aquadrives

[RichP]

An alignment of up to around 4 degrees is apparantly acceptable with aquadrive, some people use it to mount the engine flat.

There is another boat with a 1gm using the standard mounts, but his installation imo has the p-bracket a bit to far aft to use a folding prop. (His is 3 bladed)

The outboard is not acceptable for the boat, the prop regularly cavitates with even a moderate swell, and its a pig to get up and down!

[RichP]

Originally Posted by Faster

The angle on your engine beds seems quite steep - and looking at your hull form and the location of that heavy skeg means you'll need a steep shaft angle to drop the prop shaft through the hull before the skeg starts. Does Yanmar specify a maximum installed angle for the engine? I seem to remember they did and it may be something to check...

Sorry for the double post, just spotted this, on all the others i have seen, the propshaft passes through the skeg. The bearers are not that steep at all when you see them.