Conversion sail to power

[James Wellington]

Would this make any sense for guys who don't want to sail but can get this boat quite cheap? Gilbert Caroff, Chatham 60, 18 X 5.2meters, 2 X 75 hp Yanmar motors. Fuel..1000 litres.
My friend says cut off everything but the mainmast to about 10 feet or whatever. Leave boom for an emergency get home small sail. Up the fuel storage.
It seems a shame to cut off all that from a perfectly good sail boat, but if one doesn't want to sail anymore.....?
We see that there are powerboats that are about the same, like those LRC 58s.

 

[Milehog]

I have read reports of sailboats with deleted masts having very poor motion. It seems the polar inertia of the mast is important.
The intact mast is valuable assuming it is in good shape. Before I cut it, I'd find a broken mast to try instead.

 

[James Wellington]

Thanks. This boat would still have it's retractable keel, that goes from 1,10 meters to 3.2. Not sure what polar inertia is. But without the tall mast and all that fixed rigging, it should have a lower center of gravity, right?

 

[fastwave]

It makes sense if you are happy with the installed power. Changing engine can be costly.
There many ways to adjust for the motion when the mast is gone if needed.
It’s probably best to sell the mast and find a damaged one somewhere instead. Might recoup some of the cost.

 

[James Wellington]

It makes sense if you are happy with the installed power. Changing engine can be costly.
There many ways to adjust for the motion when the mast is gone if needed.
It’s probably best to sell the mast and find a damaged one somewhere instead. Might recoup some of the cost.

It's 150hp, for a long thin boat. Compare to the Artnautica, which has just 90 HP, and goes 4000 miles at 7 kts.
Yes, maybe the mast could be sold, but irrelevant. Or a short stubby one for emergencies. No standing rigging.
.

 

[rangebowdrie]

I'm shocked, shocked to find that someone would just cut a mast down.
If you don't want it, have it lifted out and keep it and all its rigging and related parts intact.
You'd still want some kind of mast/boom, (maybe two booms, one forward of the mast,) if only for easy hoisting of tenders/heavy gear.
I think you'll find that a sailboat without a mast becomes a horrible rolling nightmare in anything much beyond calm conditions.
The motion can become violent, people aboard literally get thrown around like rag dolls, it ain't a smooth ride.

 

[nemier]

I like the idea, but she'll probably roll like a ******* with the mast cut down. Just sayin'

 

[gonzo]

Sailboats with the mast down are very uncomfortable. They roll very fast (short period), which is a recipe for seasickness. I am not sure why you want to take the mast off, but if you do, a stabilizer system should be added. However, take into consideration that the uncomfortable roll will affect the boat at anchor even more.

 

[fastwave]

Guys, the rolling motion can be adjusted by cutting weight out of the keel if required. This is cheap to do. Also the fact that is a lifting keel it allows another variable to play with in terms of roll as well motor efficiency.

 

[jehardiman]

Guys, the rolling motion can be adjusted by cutting weight out of the keel if required. This is cheap to do. Also the fact that is a lifting keel it allows another variable to play with in terms of roll as well motor efficiency.

No, not really true. Modern sailing hulls are designed quite differently than modern power hulls. Sailing hulls are designed (CG, CB, Iwp, lines, etc) to be sailed heeled and generally perform worse when dead upright due to wetted surface issues. Additionally, they are not optimized for propulsion leading to sometimes significantly lower propulsion efficiency.

Remember; it is a common, but often true, adage that the most expensive boat is a free/cheap one.

 

[TANSL]

........ and generally perform worse when dead upright due to wetted surface issues

I am not at all clear about that, but in any case, it is a good topic for exchanging opinions, since I do not believe that anyone can corroborate their reasoning with facts. My opinion is that, in a hull with such rounded shapes, the wet surface of the heeled boat does not have to be very different from that of the upright boat. Therefore, the frictional resistance will not be very different. On the other hand, the heeled boat will raise many more waves than the upright boat, with the consequent increase in the resistance due to wave formation, which is always greater than the frictional resistance.
Another issue is the variation in the rolling period. The boat without a mast will have a shorter rolling period, not because it does not have a mast but, fundamentally, because it does not have the sails that slow down the rolling. I do not know why the mast cannot be removed. Nor will all the ballast that the boat can carry be needed, so it is very likely that it could all be removed. This would of course require carrying out stability calculations for the new displacement. Only then would the true effect of removing the mast and/or ballast be appreciated.

 

[Milehog]

Oh brother...

 

[gonzo]

Guys, the rolling motion can be adjusted by cutting weight out of the keel if required. This is cheap to do. Also the fact that is a lifting keel it allows another variable to play with in terms of roll as well motor efficiency.

That would make it worse.

 

[TANSL]

That would make it worse.

Why, could you, please, explain that?. Thanks in advance.

 

[gonzo]

It raises the CG