#4 Fluke Style Anchor. Boat size: 13′ to 16′. Maintain a firm hold with a modern classic. The SeaSense fluke style anchor is designed to penetrate sand, mud, gravel and grassy bottoms quickly while maintaining a firm hold. Arc welded oversized flukes pivot downward into bottom to set fast, stow flat and provide years of reliable service. Excellent weight-to-holding power ratio compared to cast anchors. Must use anchor chain and shackles for proper holding.