Question about ships

Dear Julio Gomez:

I'd vote for one of two things:

David A. Smith

Style and the desire to lift the smoke plume a little rather than a lower swirling exit in adverse conditions, I'd say??

Brian W

Dear Brian Whatcott:

I've seen that on earthbound chimneys, under certain conditions. Where a little smoke "hovers" on the leeward side of the chimney. I would think the general "oval" shape of the stack (cross section) would take care of most of this... Good point though.

David A. Smith

Brian Whatcott wrote in news: snipped-for-privacy@4ax.com:

Maybe also using the angle to take advantage of the airflow over the top of the stack to help with draw from the firebox while underway?

I imagine directing the soot and fly-ash off the high class passengers and directing towards the low payers in steerage also had something to do with it.

Ships don't have chimneys. They have funnels.

My guess is that the early funnels (mid 1800s) were slanted aft to match the orientation of the masts, with which they shared stays, or at least stay-space. Even after the masts went away, the funnels still had to be heavily stayed, and the slant remained. By the time funnels became self-supporting structures somewhere in the 20th century, I'm sure style had overtaken any functional considerations. They certainly LOOK much zoomier.

Why are the masts of sailing ships slanted aft? I suppose that it makes the structure below decks, the structure between the mast step and that supporting the backstays, more compact and efficient.

Hth, Fred Klingener

Masts of square sailers were slanted to have the sails slightly overlap and still have room to billow out. On modern sailboats the rake of the mast is an adjustment to the sails. I think, when adjusted properly the boat will have the least helm pressure when sailing to weather (into the wind.)