Interlux - Seam Compound - Brown 30, White 31 Interlux - Seam Compound - Brown 30: Is specifically designed to fill seams of wooden boat bottoms and used to fill keel joints that flex. Seam Compound Brown 30 is a tried and proven performer which remains durable and flexible after immersion, to absorb expansion and contraction of planks. Seam Compound Brown 30 exhibits excellent adhesive qualities when applied over properly primed surfaces. Interlux - Seam Compound - White 31: Is not for use below the waterline.