Boat stability question

[Whippersnapper]

You wont find any facts to support that because whether a boat is inboard, outboard, sterndrive or IPS has little or no bearing on how it behaves at anchor. First, just because the engine(s) are located aft doesnt mean that the CoG is necessarily located further aft because other weights may well have been pushed further forward in compensation (eg fuel/water/blackwater tanks, batteries, generator etc). Second, the longitudinal position of the CoG has no effect on how the boat rolls which is really the critical factor affecting how comfortable a boat is at anchor and the factors affecting that are the beam and weight of the boat, the hull design and the height of the CoG above the roll centre

True. I remember looking at the details of a boat in another thread that was available with shafts or outboards and the CoG was the same (outboards lighter but further back ending up having the same as heavier engines closer to the middle)

 

[kolyo]

True. I remember looking at the details of a boat in another thread that was available with shafts or outboards and the CoG was the same (outboards lighter but further back ending up having the same as heavier engines closer to the middle)

In this case I wonder what would make someone prefer a shaft (or an I/O) version rather than an OB one???

 

[Bouba]

In this case I wonder what would make someone prefer a shaft (or an I/O) version rather than an OB one???

Lots of reasons. Here in the Mediterranean, we park stern to. And most outboards get in the way and make it hard to get on and off the boat. Also it’s possible to damage the outboards if you hit the dock. Next, in Europe, gasoline is very very expensive, and some marinas in the UK it’s hard to buy. Because, there is a subsidy for diesel fuel. Some people don’t like gasoline because they fear fire. And finally, in France, for example, there is a tax on your engine, the formula for working out how much to pay is complicated, so you have to do this calculation before deciding which engines to use (and even which model of outboards to buy).
Personally, I love outboards

 

[kolyo]

Here in the Mediterranean, we park stern to. And most outboards get in the way and make it hard to get on and off the boat. Also it’s possible to damage the outboards if you hit the dock. Next, in Europe, gasoline is very very expensive, and some marinas in the UK it’s hard to buy. Because, there is a subsidy for diesel fuel. Some people don’t like gasoline because they fear fire. And finally, in France, for example, there is a tax on your engine, the formula for working out how much to pay is complicated, so you have to do this calculation before deciding which engines to use (and even which model of outboards to buy).
Personally, I love outboards

I much prefer outboards too!

BTW, the Mediterranean countries are no less than 27 with the only "true" ones being just Cyprus and Malta. They are IN the Mediterranean sea and not merely touching it with one of their borders like France which is not even a poor third because other countries, Greece including, have much longer Mediterranean shorelines

Anyway, I should consider myself lucky since my mooring in the Greek Mediterranean allows me to park alongside. Also diesel over here is about the same price as petrol and there is no tax difference regarding type or size of engines.

And finally, marine diesel engines being safer than (petrol) outboards has been proven to be a myth.

 

[Bouba]

I much prefer outboards too!

BTW, the Mediterranean countries are no less than 27 with the only "true" ones being just Cyprus and Malta. They are IN the Mediterranean sea and not merely touching it with one of their borders like France which is not even a poor third because other countries, Greece including, have much longer Mediterranean shorelines

Anyway, I should consider myself lucky since my mooring in the Greek Mediterranean allows me to park alongside. Also diesel over here is about the same price as petrol and there is no tax difference regarding type or size of engines.

And finally, marine diesel engines being safer than (petrol) outboards has been proven to be a myth.

One of the other problems used to be that you lose the swim platform with outboards. But that has all changed now, with beautiful side swim platform and other innovative designs. One very good thing about outboards is there is lots of room for a Seakeeper, so the stability is not a problem.
But there are still two problems. The first is where to put the tender. The second is the generator, in America gasoline inboard boat generators are common, not so in Europe

 

[kolyo]

... here are still two problems. The first is where to put the tender. The second is the generator, in America gasoline inboard boat generators are common, not so in Europe

I am planning to get an extremely lightweight 3D tender, weighing only 15 kg, which I can easily lift and stow away inflated on top of the aft cockpit bimini sun shade.

As for the generators they are (allegedly) a much higher fire hazard than either petrol or diesel engines.

 

[gordmac]

Although nominally the same I suspect outboard and inboard boats may have a different underwater hull design.