Al. boat owners, trailer question....

[OUTLAW]

I have an 18' x 62" flatbottom and I"m replacing my trailer. I have to replace bunk boards so I have a question. The old trailer has 2 2x4-6' long in the back and one 2x4 across the front. I was thinking of adding more than just 2 boards under it thinking it would be better for support but from what I'm seeing it might be overkill. For those with big al. boats, how many boards are they supported by and in what areas.

thanks

[Thin Water Tracker]

Well I have a 20ft alweld that 96 inches across the bottom and it has four 2X6 that it set on. Boat and motor weigh right at 1300lbs.