My boat falls apart when I un-anchor it?

I know this isn't scripting related, but my boat falls apart when I un-anchor it. I can't use a script to fix this, and I welded every side of every piece. What am I doing wrong?

Have you tried the terrain water? Or universal blocks and welds?

local model=Workspace:FindFirstChild("Boat") --or whatever it is
local middle_part=model:FindFirstChild("Center") --or whatever it is

if not model or not middle_part then
error("Model or middle part is missing");
end

function WeldModel(the_model)
for i,v in next,the_model:GetChildren() do
v.Anchored=false
w=Instance.new("Weld",middle_part)
w.Part0=v
w.Part1=middle_part
WeldModel(v)
end
end

WeldModel(model);

This will weld your boat together so that you can unanchor it

Samuel's method is a good solid method. Another way is: Workspace.Boat:MakeJoints ()

That might not always work, however.

You need to figure out a welding script that will weld all the parts together and attempt to make it buoyant ( If you don't know what buoyant means it means float/ ( Drive and or swim ) in the water ) If it succeeds at making it buoyant than you will be able to than either make a GUI or a tool regarding to tell you tools.

You didn't weld.