Fit New Engine, In ot Out of the Water?

[Old Bumbulum]

Prompted by a thread below about glassing in stringers I wonder if I should fit my new engine with the boat in the water. As the alignment required is to two or three thou it is not going to take much flex in the hull on land to change that. The boat is a heavyweight long-keeler but I recall how much my allegedly solid and rigid Sadler 32 flexed when set down on her keel.
How do professional engine fitters prefer to do it?

 

[pvb]

Professionals would almost always do it out of the water, as it's easier to do the heavy hoisting on land. It also makes it easier to do any adjustments to the prop shaft. It makes no difference anyway, because you'll need to align the engine finally with the boat in the water.

 

[Stemar]

No professional, but we aligned my engine in the water and rig tuned. Jerry the Rigger's a firm believer in tight rigging; when he's finished, the bolt on the heads door doesn't line up...

Worth thinking about a flexible coupling? IIRC, mine claims to accept 2-3 degrees of misalignment, which make life a lot easier, but probably need to shorten the shaft and I wouldn't want to do that between tides on a muddy grid.

 

[DownWest]

Fitted a 1GM10 and a 2GM20 recently. First was a swop for a GM and required new mountings. Second was a refit, so no alignment probs. Both times did them on the pontoon, hoisting with a ratchet winch on the boom, then swinging out to the finger. Both engines had flexable mounts and shaft seals on rubber hoses. Weights were 70 & 100kg nominal, but reduced by removing ancilaries. Tied the main halyard to the boom, close to the winch, which was secured with seat belt webbing.
Removing the bigger one was a two hour job from opening the cover to heaving into the van.

 

[bluerm166]

Without knowing the engines involved ,it may be worth checking the required water intake and exhaust i.d. against the new requirement.
I.e. When we changed out a 2GM20 both the matching new Yanmar (now indirect) and the matching new Beta called for an increased intake of 19mm i.d. and increased exhaust of 50mm.