Small gaps with concentric external fill pattern

[siva]

Selecting "External Fill Pattern" as Concentric gives good prints except I am seeing small gaps. I was OK with the octopus head having a small hole but not the base of a boat . Is this an inherent problem with concentric fill or do I have to tweak other parameters? It seems with rectilinear pattern there is a criss-cross that also makes it strong (I think) but doesn't seem to be the case with concentric (understandably for circles, I am not sure if something else can be done for other shapes).

[habloIngles]

Try increasing first layer width see if that fills in the holes

[siva]

That's really not an option because the base of the boat is actually a little above printed with support. See http://www.thingiverse.com/thing:200953