Added weight aloft

brak · #1 (**permalink**) 04-20-2009

I just had spreader bases replaced on the mast and, as part of it rigger chose to use new spreaders (the old ones required somewhat involved fitting to use with new bases and he felt that this would not be worth my expense).

The thing is - new spreaders are about 10 lbs heavier than old ones (each), so I am easily adding 20lbs aloft. (Edited: or may be it is 10 lbs added for both? I weighted them a while ago and can't really remember now. Still, not trivial amount) My boat is not a racing boat for sure, and the mast is relatively short (spreaders are about 15' above deck).

Still, would I expect to see any difference in handling? Would the boat be perceptibly more "tippy"?

Should I insist on using lighter spreaders anyway (and pay for it) or try the new ones and see if things are as bad as I my worst expectations are, first?

Generally, whats the "rule of thumb" of making things heavier up above (except "don't do it"

)?

svHyLyte · #2 (**permalink**) 04-20-2009

The added weight, which is pretty minimal considering your yacht (HR35) will have little adverse effect and may tend to make the boat marginally more stable in a seaway, rather than less, due to the increase in the roll moment of inertia of the rig. In the "olden days", once ships discharged their deck cargos, which lowered the center of gravity of the ship and made their rolls "snappy", ship masters would have sacks of coal hoisted into the rigging to slow a ship's roll in a seaway. Whether they realized the physics or not, what they were actually doing was incresing the ship's moment of inertia (the flywheel effect).

FWIW...

s/v HyLyte

brak · #3 (**permalink**) 04-20-2009

Very interesting info! I didn't think of it in terms of inertia but now that you mention it - it makes sense.

Well, thanks for the information - I guess I'll stick with the new way and find out (or, more likely, won't notice

).

sailingdog · #4 (**permalink**) 04-20-2009

If you were on a lighter boat, it might be a problem....but your boat isn't a lightweight.

HyLyte's point about the roll inertia is also why sailboats are so uncomfortable after they get dismasted... and far more likely to get rolled...

brak · #5 (**permalink**) 04-20-2009

cool. I learn something every day (this applies not just to sailing, but I really enjoy new information in this field in particular).