$V_{wood} = (0.305^2)(3)$
$V_{wood} = 0.279\,075 \, \text{m}^3$
$W = \gamma_{wood} V_{wood} = 6288.46(0.279\,075)$
$W = 1754.95 \, \text{N}$
$BF = \gamma_{water} V_{wood} = 9810(0.279\,075)$
$BF = 2737.72 \, \text{N}$
$\Sigma F_v = 0$
$F + W = BF$
$F + 1754.95 = 2737.72$
$F = 982.77 \, \text{N}$ answer