Sub Dolphin propulsion system improvement AIP type Selection for SSK Dolphin‐I
Air Independent Propulsion (AIP) type selection is one of the important parts of AIP design process. The correct AIP selection is based on analysis of many different criteria that have to be taken into account. Considerable amount of criteria and alternatives create serious problems to make a decision. The Analytic Hierarchy Process (AHP) is not simple but very attractive method that can assist to designer in AIP selection.
In fact, the AHP is a Multi‐Criteria Decision‐Making (MCDM) method that gives possibility to find the best solution among given alternative that satisfy to given group of criteria. The relevant data are derived by using a matrix of pair‐wise comparisons. These comparisons are used to obtain the weights of importance of the decision criteria. If the comparisons are not perfectly consistent, then it provides a mechanism for improving consistency.
Sometimes it is very difficult to define the objective preference value for criteria and alternatives. Very often the criteria conflict with each other. Even more often the objective data are very expensive to collect. In this case is used subjective expert assessment of probability to satisfy given criterion by means of each alternative.
All stated above problems are concerned AIP selection. It should be remembered that selection of criteria, determining of criteria number and criteria ranking (setting of relative importance of criteria) are subjective processes. Very these processes creates conditions for permanent hot discussions.
To obtain the correct results AHP requires using expert assessment to define weights and priories of criteria and priorities of alternatives for every criterion. Obviously, any deliberate or undeliberate incorrect application of this statement leads to incorrect calculation results.
To be sure that results are correct it is very important that every criterion, its pair‐wise comparisons, the relative importance of one criterion over another would be proven.
Presentation contains data that allow for readers to evaluate rightness of AIP type selection independently, without assistance.
All calculations with MathCAD were performed.
The Dolphin‐class submarines is actually two – Dolphin‐I and Dolphin‐II sub‐classes of conventional diesel‐electric submarines developed and constructed by TKMS Howaldswerke‐Deutsche Werft AG (HDW), Germany for the Israeli Navy especially.
In 1999‐2000, three conventional diesel‐electric non‐AIP submarines Dolphin‐I class [Dolphin; Leviathan (Whale); Tekumah (Revival)] with relatively short submerged endurance were commissioned and are in active service in Israel Navy for 15 years. These boats are fitted with modern armament, have upgraded control and Anti‐Submarine(ship)‐Warfare systems. However, these boats have short submerged endurance as they are not fitted with Air independent Propulsion (AIP) systems. if to suppose that indiscretion ratio of boat is about ~5% at patrol mission and battery charging duration is ~4 hours then submerged endurance will be 80 h (3.33 days).If a boat has submerged speed ~3knot then underwater range will be about 240 nm.
In order to recharge the battery the submarine has to surface up to snorkel depth and to switch on a diesel‐generator. The using of diesel engines at snorkel depth is a noisy operation, which increases submarine’s vulnerability drastically, especially if it take place in patrol zone. To realize patrol mission and to come out of zone unsensed during 10 – 14 days submarines Dolphin‐I have to be retrofitted from non‐AIP boats into modern AIP submarines that will be able to solve both tactic and strategic tasks.
Some words about Analytic Hierarchy Process (AHP).
The AHP method is very attractive method really. However, it should be noted that mathematical tool of AHP can conceal from designers some important basic requirements of the method. The formal approach in this case can be harmful.
Obviously, you will ask me: What dangers are hidden under mathematic tool?
- subjective selection of criteria and alternatives and amount of criteria;
- subjective setting of so called “Criteria Ranking” (criteria relative importance).
Very subjective approach in selection of criteria and determining of relative importance of criteria create conditions for permanent hot discussions.
To obtain the correct results, AHP requires using expert judgments to define weights and priories of criteria. Any deliberate or undeliberate incorrect application of this statement leads to incorrect calculation results.
To be sure that results will be correct it is very important that every criterion, its pair‐wise comparisons, and relative importance of one criterion over another have to be proven.
SUB DOLPHIN PROPULSION SYSTEM IMPROVEMENT
Table of Contents
|1||RETROFITTING OF NON-AIP BOATS INTO AIP SUBMARINE||8|
|2||AIP TYPE SELECTION FOR SSK DOLPHIN-I. CRITERIA FOR SELECTION||14|
|3||THE ANALYTIC HIERARCHY PROCESS. CRITERIA & ALTERNATIVES SUBSTANTIATIONS||18|
|4||AIP TYPE SELECTION FOR SSK DOLPHIN-I. THE ANALYTIC HIERARCHY PROCESS||46|
|5||AIP TYPE SELECTION FOR SSK DOLPHIN-I. THE ANALYTIC HIERARCHY PROCESS WITH MATHCAD APPLICATION||80|
- Title – ANALYTIC HIERARCHY PROCESS APPLICATION to Select AIP type for non‐AIP Submarines (Draft Presentation)
- Classification – UNCLASSIFIED Author – Bakst A.
- Issue Data – 2014‐08
- Updated – 2016‐04
- Pages (Slides) – 92 (including Cover and References) (including Cover and References);
- Cover – 2 slides;
- Tables – 24;
- Figures – 28 (pictures, graphs);
- References – 17;
- Format – Adobe PDF
- Size – 1.54MB
- Price – 50USD
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