Noun:

Outrigger,

outriggers's Usage Examples:

These boats are either plain dug-outs, with or without outriggers, or regularly built by planks tightly laced and well caulked to an excavated keel.

I managed to find some sill sections on ebay, and I bought some new front chassis outriggers from a specialist over the phone.

Except for the trireme none of these galleys had outriggers they were all worked over the gunwale.

long, in the hope that when the speed reached a certain point it would leave the rails, but it was prevented from rising more than an inch or so by four arms, or outriggers, furnished with wheels, which projected from its sides and ran under an inverted wooden upper or safety track outside the railway track proper.

They were a form of whiff, with roughly the same dimensions, fitted with sliding seats and full outriggers.