In the previous article, different part solutions were combined to find three combined solutions. Here they will be compared using weighted criterias.
What is a weighted comparison?
A weighted comparison is done by chosing the characteristics that are being compared and then distributing 100% over them. This is done in relationship on the importance of the specific function for the overall product.
The product itself is judged for each criteria for how much percent it can fulfill the function. A perfect fit would be 100%.
The abilities of the product is multiplied with importance factors and the total shows how well the overall solution can fulfill the criterias of the requirement list.
A short example: The function safety for a helmet is weighted 90% and the weight of the helmet only 10%. A design out of Iron is heavy (10% ability to be light) is also very safe (95%). The design is better then a helmet out of cardboard, that is not very safe (5%) but also very light weight (100%).
What is compared?
By comparing the three ships to ech other, the deciding parameters have to be declared. The requirement list gives the most important characteristics and even sets a comparative value. The different Solutions are then judged according to these characteristics.
In this example the goal is a trading vessel, that may have to travel long distances through unknown and dangerous territory to trade goods. The best spaceship to do this is fast, cheap to buy and maintain regarding repais and fuel, gurantees a safe trip, can carry a lot of cargo and invites others to come and trade.
Thus the following criterias are chosen:
| Criteria | Description | Importance |
|---|---|---|
| Speed | How fast is the spaceship | 20 |
| Cost | Purchase and maintenance costs | 10 |
| Safety | Safety of travel and trade | 20 |
| Capacity | Amount of cargo | 35 |
| Peace | How threatening is the ship | 15 |
| Sum | 100 |
The criterias are valued diffently strong: It is more important for the ship to carry a lot of cargo then being cheap, because carrying more goods can increase the efficiency, even if the ship is expensive. Being peacefull is of little importance. In the requirement list this criteria would be "if possible wish", since it is not necessary but favorable.
The candidates
This short introduction for each spaceship should show what abilities it has. For more information of their components, refer to the previous article.
Spacetruck
Equipped with a hyper drive, antimatter reactor and a point-defense-laser the Spacetruck is very fast, safe and has a very peaceful impression. The price for the hyper drive, antimatter generator and the animatter itself is very high and the cargo capacity is limited to enable the high speed. The laser canons distributed over the vessel have only short range and a clear defensive character.
Nuke Express
This spaceship is using the orion drive to reach high speed, which is still lower than its competitors. The nuclear fusion reactor delivers enough power for relatively low costs. The safety is very low due to the slow speed and the danger of the propulsion system, generating constant nuclear explosions behind the ship. The cargo capacity is therefore small and the ship itself is extremly threatening to other traders. Even thougth it is missing actual weaponry.
Hard Freight
Using a quantum-crystalline armor the spaceship can plow through every resistance that may stand in its way. Powered by a naquadah reactor, it is not very fast but can take shortcuts through the warp, the paralell dimension of horror and chaos. This combination makes this variant as expensive as it is safe. It is able to carry a lot of cargo, because the ship does not have to accelerate its mass to high speeds to cover a far distance. The extremly defensive strategy makes it a very unthreatening ship.
Comparison
The spaceships are now compared by rating their seperate abilities on a percent scale, weighting them with the earlier declared factor and then adding the resulting products to get the overall ability of the ship.
| Model | Speed | Cost | Safety | Capacity | Peace | Sum |
|---|---|---|---|---|---|---|
| Factor | 0.2 | 0.1 | 0.2 | 0.35 | 0.15 | 1 |
| Spacetruck | 90 | 20 | 60 | 50 | 70 | 60 |
| Nuke Express | 50 | 100 | 20 | 30 | 10 | 36 |
| Hard Feight | 70 | 50 | 70 | 100 | 60 | 77 |
This table gives a good overview over the necessary criterias, their importance and how good the different solutions (here spaceships) are at solving these problems. The sum then serves as a good comparison.
Result
The Nukeexpress is not able to convince with its low price, because it lacks in the importanc categories: speed, safety and cargo capacity. It is a close win for the Hard Freight over the Spacetruck, mainly because of the best safety and capacity, the most important factors in this comparison.
This will be enough for spaceships so far. The product process is almost done and the only thing missing now is the detailed coinstruction of and the documentation with technical drawings, partlists etc.
But this will be a topic for the next articles.
Thank you for reading!
to be continued
Did you already read...
Part I: What does an Engineer do?
Part II: The first STEP on the way to YOUR Product: Inventing
Part III: The Other Kind of Research: Put your IDEA into the World
Part IV: The Requirement List: The ENGINEERS way of TAKING AIM
Part V: Function Analysis: No Maths but still solving Problems
Part VI: Part Solutions: Solving one function after another
Part VII: Combined Solutions or How to build a spaceship