The advantage of building and testing a prototype is that issues with the design and specifications can be discovered and resolved before the boat goes into production. The downside is that prototyping is very costly and that is why testing a full size boat before production is seldom, if ever, done.

*Please note: The Offshore 42 has not been priced yet. The cost figures are purely to provide estimates for explanation purposes and will be adjusted once the Offshore 42 has been priced by a yard.

Option 1: Building a prototype:

  • $800,000 for prototype.
  • After 6 months of testing, the prototype is sold off as an improved, used boat for $160,000.
  • The money for the prototype needs to be financed and paid back with interest.

This scenario gives the following breakdown:

  • The 6 months of testing will cost $24,000 in interest payments.
  • At start of production we owe the investor $664,000 ($824,000 minus the $160,000 the prototype is sold for).
  • $29,000 per boat is added to the sales price to cover what is owed to the investor, (assuming 25 boats over three years).

Option 2: 5 prototypes

Another option is that 5 boats are built at production cost. Four of them are pre-sold at a discounted price and the fifth remains the testing boat for 6 months.

  • Selling off four right away untested for $160,000 a piece, with full disclosure agreement in place. Risk of fixing mistakes is owners risk and the designer will share improvement drawings with these owners if any improvements are made to the prototype.
  • After 6 months the prototype can be sold off as a used and improved boat for $160,000
  • We can sell 21 additional boats adding up to a total of 25. It will take 2.5 years to build the remaining 21.

This scenario gives the following breakdown:

  • 5 boats will be commissioned from the yard.
  • 4 boats will be sold right away at discounted price.
  • The remaining boat will be tested and improved over a period of 6 months.
  • The 6 months of testing will cost $10,800 in interest payments.
  • Prototype will be sold off for $160,000.
  • At start of production we owe the investor $210,800.
  • $10,800 per boat is added to the sales price to cover what is owed to the investor (assuming 21 boats over 2.5 years).

Option 3: Mocking up

Instead of building a full size prototype that can actually sail, it is also possible to build parts of the boat with low cost material. This has the advantage that you can sit in it, walk through it and pretend that you are turning a winch.


  • Cost of mocking up the cockpit and dodger: $10,000.
  • Cost of partial mock-up of interior: $15,000.

The break down would look like the following:

  • Mockup is first phase, total cost $25,000.
  • Building and ‘testing’ the mock-up will take 2 months.
  • Interest paid on investment during building and testing is $250.
  • At start of production we owe $25,250 to the investor.
  • $1,100 per boat is added to the sales price to cover what is owned to the investor (assuming 25 boats over three years).

Option 4: No Prototype 

The advantage is that production can start right away and that there is no increase on the final price of the boat.

As we all know, an untested boat could lead to unexpected cost to fix problems that have not been caught during the design or building process. The kind of mistakes that have occurred with other boat builders include:

  1.                 Poor sailing performance.
  2.                 Poor stability.
  3.                 Construction that is too flexible.
  4.                 Keel that is not attached properly.
  5.                 Unbalanced rudder.
  6.                 Unbalanced rig.
  7.                 Pounding on the waves upwind.
  8.                 Excessive vibration in the engine and drive train setup.
  9.                 Wrongly placed deck hardware or handgrips.
  10.                 Ergonomic errors in cockpit seats and interior.

What is the likelihood of this happening, and what are the cost to fix it if required?

1         Poor sailing performance. The Offshore 42 concept of hull, rig, keel and rudder is by no means deviating from the majority of boats that are already out there. Therefore there is a lot of data available to predict the performance of the boat that can be directly applied to the Offshore 42. As long as the right ratios for sail area vs weight, center of gravity vs boat width, righting moment vs displacement, length vs weigh etc. are chosen, the chances that the sailing performance is poor is slim to none.

2         Poor stability. Stability is not guess work, it can be calculated in great detail and there is no risk involved when calculations are performed correctly.

3         Construction too flexible. This means that the hull flexes when sailing up wind or in waves. This could result in doors or lockers not opening. When safety margins for structural stress are closely approached, these things can happen. They result in decreased upwind performance and annoyance while sailing. Flexing will eventually result in a boat that starts leaking on various joints. At Offshore Sailboats we consider this unacceptable. The chances of this happening however, are negligible when proper hull scantlings with decent safety factors are used.

The law requires that certain sets of regulations are followed when designing constructions. These regulations determine what assumptions need to be made for water pressure, point loading, safety factors and maximum allowable stress for the materials that are being used. These requirements are however minimum requirements that you have to comply with, and the rules are fine-tuned based on accidents that happen. Since most recreational boats are not going offshore a lot, their influence on the regulations are small but especially for ocean going yachts, structural integrity is important. Therefore we have deviated from the ‘standard’ safety factors and have applied higher factors that we see as fitting for serious oceanic use. We are confident that there are no structural risks.

4         Keel that is not attached properly. Over the last couple of decades, various keel failures have occurred and many reports have been written about them. In many of those cases, grounding calculations had not been performed. At Offshore Sailboats we are of the opinion that the mandatory safety factors used in the yacht building industry are not sufficient, therefore we have designed the keel structure with the safety factors we see fit for offshore use. Calculations with larger safety margins than usual are used for the Offshore 42 as well as grounding calculations with speeds well in excess of the hull speed. This is based on the Offshore 42 sailing a lot of miles where maintenance and inspection intervals are far between. Chances of issues arising in keel structure are therefore close to nonexistent.

5         Unbalanced rudder. This would result in heavy steering which is tiring and annoying for the crew but also increases power consumption for the autopilot. The Offshore 42 is a very moderate boat when it comes to hull shape and rig design. There are many boats available that are very similar. The balance of the boat and rudder can therefore be quite accurately calculated. The chances of anything going wrong here are minimal. Though if it does happen, a new rudder blade with an adjusted design would cost a maximum of $1,000-$1,500 per boat.

6      Unbalanced rig. This is a similar story to the rudder, the chances of anything being wrong with it are very minimal as it is a very standard rig on a very moderate hull shape. If something is wrong, in most cases it can be corrected by mast and sail trim at no cost.

7         Pounding on the waves upwind. This has mainly to do with the hull shape in relation to the weight distribution over the boat. The more concentrated the weight is in the middle of the boat, the smaller the chance of the bow section pounding in waves. Any sailboat will slam on a wave once in a while, the question is how often and how hard will this boat do it. There is very small risk of anything being wrong here.

8         Excessive vibration in the engine and drive train setup. The engine is a sensitive combination of engine foundation, propeller shaft, bearings, strut, engine, gearbox, engine mounts, exhaust etc. This will all be designed and delivered by the same company that has 20+ years of experience with these kind of small engine setups. Therefore the chances of anything being wrong here are negligible, in case something is wrong it can be fixed for a couple of thousands of dollars or less.

9         Wrongly placed deck hardware or handgrips. It all depends on the human body and physical strength as well as the range of motion from the person involved. What works for somebody that is 6’4 and 250lbs, will most likely not work for a 5’4 and 120lb sized person. The locations of all items are therefore different for any person and can only be located approximately as there is no right spot. The cost of moving deck hardware around is not great. The optimum location that will work for the largest spectrum of people can be found with help of a mock-up, no prototype required.

10     Ergonomic errors in cockpit seats and interior. Very similar story as described above regarding the location of the deck hardware. The ergonomy of the interior can be determined with the help of mock-ups and does not require a prototype to be built.

The reality is, the added cost of a single prototype (option 1) is more expensive than fixing the cost of any mistake that can be made on such a boat as the Offshore 42. Option 2 costs less than half of option 1, but still represents more money than all the possible mistakes added up would cost. A mock up on the other hand is almost negligible in cost if looked at it on a per boat ratio. But a mock-up can prevent some annoying errors from happening, the cost of having to fix those errors are greater than the cost of the mock-ups.

Conclusion: From an economical and practical standpoint, building mock-ups rather than testing a prototype is way more sensible and much less time consuming. The mock-up option will eliminate potential errors and give the greatest benefit without reducing quality or disproportionately impacting cost.


6 thoughts on “Prototyping

  1. Andrew Gregory says:

    This all seams to make a lot of sense. However I think option 2 would possibly be the best option. However you need 4 people who would be happy to take the first 4 yachts. Unfortunately at this very movement in my life and lack of recent sailing skills I would not be able to be one of these 4. Also I would be interested to see like on the other Blog Adventure 40 it would be good to see every bodies feed back and comments etc. Keep up the good work. I’m still very interested.


    • offshoresailboats says:


      Glad you are interested. Once the Offshore 42 has been quoted, we will disclose the price and ask for everyone that is interested in purchasing an Offshore 42 to come forward. For option 2 to work, we would need 4 boats to be ordered as well as an investor who could fund the 5th for testing. We are also interested in seeing more people getting involved in the comments. Thank you for your input.



  2. Timo Giling says:

    For the interior I think it’s much more sensible to make a digital 3D or even better a VR model, rather than a physical mock-up. The initial cost of the model may not be that much lower, but there is a lot to be gained in flexibility and being able to ‘transport’ it to the customer. Also, no storedge needed.


  3. Offshore Sailboats says:

    Hi Timo,

    Thank you for your input. Our main concern is the ‘feel’ that people have when sitting down in the cockpit, is that winch in the right place? Does it sit nicely under 20 degrees heel? Does it fit a person that is 2m (6’4″) tall and skinny as well as a 1.5m (5′) person that has a few extra pounds. Or any other combination of common body type. Similar questions for the galley, can you reach that one cabinet that is on the far side, how close do you need to hang over the stove to reach that cupboard? How is the grip in the galley when under 20 degrees heel?

    Even though you can learn a lot from a 3D model or a Virtual Reality simulation, I’m afraid that it does not provide the detailed answers we are looking for. I have made several 3D models before for this reason, but I must admit never to have worked with VR models.

    Best regards,


  4. Bill Attwood says:

    You had better amend your home page:
    “All of our models are tested extensively offshore during the prototyping phase.”


    • offshoresailboats says:


      Although we are only planning on creating the mock-up as a first stage prototype, there will be a good testing portion for the first hull before it is delivered to the customer. This is to make sure that all of the systems are functional and that there are no irregularities. This would likely happen during the delivery of the boat, as it is unlikely our first customers will be in the same place that the hulls are built.


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