In regards to the Gulf Explorer 16 plans, it includes:

• 15 sheets in total (9 x A1 sheet size and 6 x A0 sheet size - full size bulkhead patterns)
• Full size patterns for bulkheads/ stem frame and transom
• Builders manual
• Bill of materials
• Over 150 build photo's for you to preview and assist with your build (A picture tells a thousand words" as the saying goes)
• Tip's and Tricks" e-book for building your boat
• Actual Performance results with various outboards/ props showing speed/ fuel consumption and more
• Plus a lot more

Below is an example of the type of plans you receive

Yes.
We use the ABYC standard (https://abycinc.org/). (We do not use the AS 1799 standard, as we feel that this standard is full of "holes). Using the ABYC standard, all boats under 20ft MUST meet LEVEL flotation. It also means that the boat must meet certain stability criteria in regards to traverse stability, wind heeling criteria and max Hp allowed.
The Gulf Explorer 16, as designed exceeds the requirements for LEVEL flotation compliance.  This covers the boat itself/ outboard/ people and cargo.
This standard is accepted worldwide. (Australia/ USA/ Canada and the EU)

We do not design our boats to meet BASIC flotation. To me, "Basic" flotation is dangerous.
Hope this helps

So… what is Ply/ composite construction?

The term “composite means that if you use 2 or more materials in your construction layup, you must take into account for the mechanical properties of each material used. i.e. with Plywood and glass used we have to take into account for the materials Tensile strength/ Bending strength/ compression strength/ Shear strength and Modulus of Elasticity) in your engineering calculations. When you do this, its now  "composite" construction.
Once it passes Tensile strength and bending strength for a particular area, we move to the next section. This method of engineering is applied throughout the whole boat.

Now… simply building a plywood boat and wetting out some glass on it is not composite construction. Its just a plywood boat with glass laid on.

All our Plywood and Strip plank designs are engineered as composites and in this regard, we engineer out boats to “Class” rules. In other words, we use Commercial ship standards. Here we use ABS or the "American Bureau of Shipping (https://ww2.eagle.org/en.html)

Here’s just one small area within one of our designs (as an example) of the calcs we do with all our designs.

I hope this helps

Mark Bowdidge (MRINA)

No.
By doing so, your:

1/ Making the boat too light. This means the boat will float higher in the water, exposing the chines which in turn results in the moment of inertia of the waterplane being reduced which results in an unstable boat.

2/ Taking the weight out of the bottom of the boat also raises the overall centre of gravity which further adds to an unstable rolly boat. Why? Plywood has a density of approx. 600 kgm^3, whereas foam has a density between 80-240 kg/m^3 (pending foam core used). So in effect,  you've taken out between 60% to 87% of the weight that's down low. Whoops. Now you have a serious problem with stability.

3/ The boat will become too "flighty" when on the plane.

BUILD THE BOAT AS PER THE PLANS and you won't have an issue.

No.

See above topic "Can I replace the internal structure with foam core" except now its even worse.

BUILD AS PER THE PLANS

No.
Aluminium construction requires a different method of construction and scantlings. Also, being that aluminium is far heavier compared to Ply/composite construction, everything changes. Weight/ power/ stability/ seakeeping/ safety standards and more. It all changes. This means that the boat as a whole will need to be re-designed/ re-engineered/ re-drawn and throughout all this, making sure it meets the required stability and safety standards and flotation standards in the event of swamping. (Our boats meet LEVEL flotation requirements, not BASIC flotation.)

No I do not.
So please don't ask, as refusal may offend