Stepped Hulls, Trim Tabs

brucehawsker · 18 April 2006, 23:52

OK, you experts.

Why are some of the hulls stepped - ie have major discontinuities as you progress from bow to stern. Is this something only for bigger ribs?

Also why do they have metal plates on the back - I gether they are called trim tabs.

Do I conclude that for a sub 7m rib these are inappropriate?

fast fred · 19 April 2006, 00:57

steps are more for speed, thay pull air in, and or brake the clinging of the water on the surface of the hull, rule number one on go fast on the water is
" you must get your hull out of the water" steps help

trim tabs, ya you really don't need them under 7m, thay make auto ones kinda nice for smaller hulls with heaver outboards, keeps the nose down.
used to level off big hulls, a lot depends on the hull,
this hull is 7.1m she got 235hp on it when you lite it hole shot she comes up and she will start to lean left cuz of torque, would be nice to have tabs to to balance her out,

Brambles · 19 April 2006, 18:36

Quote:

Originally Posted by brucehawsker

OK, you experts.

Why are some of the hulls stepped - ie have major discontinuities as you progress from bow to stern. Is this something only for bigger ribs?

Also why do they have metal plates on the back - I gether they are called trim tabs.

Do I conclude that for a sub 7m rib these are inappropriate?

Trim tabs can help all boats in certain sea conditions - eg when you still want to press on & need to keep the bow down. On a larger boat they also help to level her out, as some have a tendancy to lean into the wind.

Ian