Catamaran designs and implications for the PLAN

crobato said:

Let me get this straight. You're suggesting that a picket line has to be made from origin to destination. A picket line of ships lined up like a great wall.

All you really need to do is set up zones of control, or corridors where each set of escort vessels have a responsibility of patrolling. When that exercise is done, it is no more costly than setting up a convoy. The problem of a convoy is that whoever you are supplying to is at the mercy of this convoy, so he won't get his supplies in time and when he needs it the most. This is unlike if you have a ferry that can quickly bring in supplies when you want.

When you have sea superiority you are going to set up these zones anyway.

Now who can threaten the cat ferry? It has to be a warship that is fast enough to catch it sustained at over 30 knots and that list really thins down.

Now about the Sea Fighter. Take a look at its hull. SWATH or not, it looks a lot more streamlined than you suggest it to be. That gives it quite a bit of top speed, the Sea Fighter is indeed fast, and no reason why it won't be uneconomical. As a matter of fact, the hull design here reminds us of another cat hull we know quite well.

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There is nothing to suggest its slow but fast. Given the suggestions of future ships, nothing to indicate that it is uneconomical either.

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1. You have to keep in mind aerial threats as well. A slower convoy may be more vulnerable to attack, but they are better defended. A fast catamaran all by itself because the escorts and support ships can't keep up is dead meat in a hostile environment. 50 knots an hour won't protect you from aerial opponents, and with the range and speed of aircraft today compared to World War II, where having high speed was an asset in the Atlantic Ocean.

2. These ferries are almost always made out of the aluminum. Out of 46 fast ferries built until 1995, only 3 of them were built out of steel, and the 3 built were monohulled. Aluminum is not used in warships because it has a low melting point. We seen the effects of aluminum in ship fires, and ships going into harm's way need to be built in a way so that they are resilient to fires.

3. SWATH is a more costly, more maintenance intensive, and is a design that requires more power to be propelled at the same speed as comparable catamarans. It's also slower than a comparable catamaran of the same size. I can pull out a report written in April 1995 by the firm Nigel Gee and Associates Ltd, a British-based consulting firm specializing in advanced and specialized ships and boats, for the construction of fast ferries which points out that SWATH, although it offers great stability, needs up to 80% more power to achieve the same speed as a equivalent wave-piercing catamaran, and thus should be avoided unless the expected route conditions are extremely rough, as operating costs are much, much higher. In comparison, a monohulled fast ferry will require up to 30% more power than a equivalent catamaran.


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In comparison to Sea Fighter, HSV 2 Swift, a 98m long by 27m wide wave piercing ferry weighting 950 ton standard is powered by 4 Catapillar 3618 diesel engines, each giving out a maximum of 9,652 bhp for a total of 38,608 bhp. Sea Fighter, a slight smaller ship, needs two MTU 595 diesel engines providing 4,320 bhp each and two LM2500 gas turbines, providing 32,000 bhp each, for a total of 72,640 bhp, almost twice the amount of power for a slightly smaller and lighter ship that travels at max speed only a smidge faster than a wave piercing catamaran (45 knots vs. 50 knots).

Pointblank said:

1. You have to keep in mind aerial threats as well. A slower convoy may be more vulnerable to attack, but they are better defended.

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Not necessarily. The longer you are the sea, the more you are vulnerable. The larger your fleet, the more obvious that you will be detected

A fast catamaran all by itself because the escorts and support ships can't keep up is dead meat in a hostile environment. 50 knots an hour won't protect you from aerial opponents, and with the range and speed of aircraft today compared to World War II, where having high speed was an asset in the Atlantic Ocean.

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That wont' change with a monohull or a catamaran. Use zoned corridors, where air defense vessels would patrol a certain section of the sea. You don't call it fleet air defense for nothing.

2. These ferries are almost always made out of the aluminum. Out of 46 fast ferries built until 1995, only 3 of them were built out of steel, and the 3 built were monohulled. Aluminum is not used in warships because it has a low melting point. We seen the effects of aluminum in ship fires, and ships going into harm's way need to be built in a way so that they are resilient to fires.

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The same complaint is made with the Sea Fighter. Except that it is no longer sticking. One of the LCS has a superstructure made of aluminum, while the other LCS is made entirely of aluminum. The Houbeis appear to be made of aluminum, while the Vicksby is made of composite which is non repairable material.

although it offers great stability, needs up to 80% more power to achieve the same speed as a equivalent wave-piercing catamaran, and thus should be avoided unless the expected route conditions are extremely rough, as operating costs are much, much higher. In comparison, a monohulled fast ferry will require up to 30% more power than a equivalent catamaran.

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And yet you check out the Sea Fighter's hull. You can see from that picture, there is nothing draggy about it, and it is a streamlined as any wave piercing catamaran. The definition of SWATH vs. wave piercing is definitely very loose here. In fact the shape of the hulls in Sea Fighter is quite like the Houbei's. This is a ship that can clock 90 km an hour.

Question: What's the bulge under the center of the hull on the 2208 used for?

Not suitable for rough seas huh.

These Houbeis are about to fire their missiles in the recent PLAN exercise in the South China seas while the Philippines is getting blown over by a typhoon.

crobato said:

Not suitable for rough seas huh.

These Houbeis are about to fire their missiles in the recent PLAN exercise in the South China seas while the Philippines is getting blown over by a typhoon.

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Naval architects will state that a wave piercing catamaran rides extremely roughly on rough seas. You can dampen it out using stabilization systems, but for transport usage, the handling of such cats in rough seas is something left to be desired. SWATH and monohull forms are superior if you need to operate in rough seas for extended periods of time. I bet the crew when they got back to base were probably tossing their lunches in such conditions.

If you take a look at the various fast ferries operations around the world, note that whenever there is a storm in the area, most fast ferry operations get cancelled. Why? Because the ships will get tossed around more than a similar capacity conventional ferry, resulting in a less comfortable experience for the passengers, and potentially, damage to vehicles parked inside.

They can toss their lunches later for all that matters is that during the meantime, the Houbeis were able to conduct missions and fire missiles in rough brown waters (not far a way, a Philippine fishing vessel capsized). You need to account for how much is the actual below waterline displacement for these vessels as this is not a typical wave piercing cat.

crobato said:

They can toss their lunches later for all that matters is that during the meantime, the Houbeis were able to conduct missions and fire missiles in rough brown waters (not far a way, a Philippine fishing vessel capsized). You need to account for how much is the actual below waterline displacement for these vessels as this is not a typical wave piercing cat.

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Did those boats just fired missiles from that pic you've posted? It still appears like there is no armament in those boxes? Either way, that camo looks like it's working really well in that environment.

joshuatree said:

Did those boats just fired missiles from that pic you've posted? It still appears like there is no armament in those boxes? Either way, that camo looks like it's working really well in that environment.

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It looks like for me they were preparing to be fired. According to reports, Houbeis live fired in the exercise. Well, just about everything the PLAN threw into that exercise did from Sovs doing Sunburns to Kilos doing Klubs.