How to make a working boat in new Roblox water terrain???

Use a VehicleSeat with your boat model and it should work.

Try a VechicleSeat with your boat (like incapaz said) and then you have an option for welding:

a. You can use a welding script from the toolbox.

b. You can use weld constraints.

c. Simply put welds on the part itself.

Hope this helps!

EDIT:

So, the VehicleSeat is not working. This is probably the problem: The VehicleSeat should be referenced by a script.Here are the steps:

1. Weld all the parts together.
2. Create a BodyVelocity on one of the parts.
3. Set the MaxForce to a high number.
4. Add a VehicleSeat to the boat that is also welded.
5. Add the script with the code below to the VehicleSeat:

local seat = script.Parent
local velocity = seat.Parent.BodyVelocity

seat.Changed:connect(function(property)
    if property == "Throttle" then -- You are trying to go forward.
        velocity.Velocity = Vector3.new(10, 0, velocity.Velocity.Z) -- You might want to change this depending on how your boat is rotated.
    elseif property == "Steer" then -- You are trying to turn.
        velocity.Velocity = Vector3.new(velocity.Velocity.X, 0, 10) -- You might want to change this depending on how your boat is rotated. 
    end
end)

Hope this helps!

treat it as actual water, the density of all parts of the boat will decide rather if the boat sinks of floats, i usually use bodythrust to move boats in water, and i definitely recommend using a body gyro so that it wont capsize

Ok so, all you have to do is add a VehicleSeat and add inside of it a, BodyGyro, BodyPosition, and a BodyVolocity then add a script inside the VehicleSeat and Paste/Type this in:

script.Parent.MaxSpeed = 500 
script.Parent.BodyPosition.position = script.Parent.Position
script.Parent.BodyGyro.cframe = script.Parent.CFrame
value1 = 0
while true do
wait()
if script.Parent.Throttle== 1 then
if value1 < 41 then value1 = value1+1 end
script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*value1
end
if script.Parent.Throttle == 0 then
value1 = 0
script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*value1
end
if script.Parent.Throttle== -1 then
if value1<31 then value1 = value1+1 end
script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*-value1
end
if script.Parent.Steer == 1 then
script.Parent.BodyGyro.cframe = script.Parent.BodyGyro.cframe * CFrame.fromEulerAnglesXYZ(0,-.1,0)
end
if script.Parent.Steer == -1 then
script.Parent.BodyGyro.cframe = script.Parent.BodyGyro.cframe * CFrame.fromEulerAnglesXYZ(0,.1,0)
end
end
----the plate boat script is by Starmarine5405 on scriptinghelpers.org

or take this model: https://web.roblox.com/catalog/03540884212/redirect

Here, I made an updated version of StarMarine5405's script. The slowing down and reversing is smoother now.

I also changed some speed variables to fit my design, but those do not need to be changed.

script.Parent.MaxSpeed = 20
script.Parent.BodyPosition.position = script.Parent.Position
script.Parent.BodyGyro.cframe = script.Parent.CFrame
value1 = 0

while true do
    wait()
    if script.Parent.Throttle== 1 then
        if value1 < 18 then value1 = value1+0.5 end -- The 18 should be around the MaxSpeed
        script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*value1
    end
    if script.Parent.Throttle == 0 then
        if value1 >= 0.25 then
            value1 = value1 - 0.25
        elseif value1 <= -0.25 then
            value1 = value1 + 0.25
        end
        script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*value1
    end
    if script.Parent.Throttle== -1 then
        if value1>=-10 then value1 = value1-0.5 end -- The 10 is the maximum reverse speed
        script.Parent.BodyVelocity.velocity = script.Parent.CFrame.lookVector*value1
        wait()
    end
    if script.Parent.Steer == 1 then
        script.Parent.BodyGyro.cframe = script.Parent.BodyGyro.cframe * CFrame.fromEulerAnglesXYZ(0,-.02,0) -- Change -.02 to your turn speed value (negative)
    end
    if script.Parent.Steer == -1 then
        script.Parent.BodyGyro.cframe = script.Parent.BodyGyro.cframe * CFrame.fromEulerAnglesXYZ(0,.02,0) -- Change .02 to your turn speed value
    end
end
----the plate boat script is by Starmarine5405 and modified by BetaTrivus on scriptinghelpers.org