+3 MAST BASE CASTING H18 60641031 $68.99 In stock Quantity: 1 Add to Bag Product Details UPC: 792176555247 Brand: Hobie Part #: 60641031 Hobie 18 Mastbase Casting Hobie factory replacement black mast base casting for the Hobie 18. Use four #5032 rivets for installation. Save this product for later Favorite