Like the Gryphonians, the Yabaran planned to invade the Earth, but had to cancel when a gigantic asteroid crashed into their planet. Why did they let an asteroid crash into their planet? Instead of doing the smart thing and just using one of their ships to nudge it off course, they tried drilling to the roid’s center and detonating a bomb. They were about a fraction past the surface when the thing crashed into the home world.
In any event, the Yabaran were, unlike the Gryphonians, preparing for direct conflict. Their main force was going to be aquatic. They were going to land deep in the oceans and deploy from there. Though they never materialized, their plans provide a unique opportunity to discuss fighting on Earth’s oceans and waterways.
First off, should you even bother with a sea fleet?
Tough question, but I’m going to recommend it. Keep in mind, the Earthlings have hundreds of subsurface craft, both military and civilian. The military vessels represent some of the most sophisticated weapons systems in the terran arsenal. These ships pack a major punch. They have to be taken out, sooner or later. If you can catch them while they’re in port, then you can destroy them with air or even land forces. But the odds are a large portion of these assets will escape to the open ocean.
You could leave your orbital assets to track and destroy the surface fleet. But that might command too much of their attention, making them unavailable for land targets. And it’s difficult to track a subsurface craft from orbit. The ocean is great at dispersing heat signatures. Wakes can be confused with biologics. The way to corral or eliminate the subsurface vessels is to go into the seas after them.
Another good reason to include a sea fleet in any invasion attempt is several major targets lie next to a shoreline or by a river. It would be useful to have an amphibious landing capability.
As a strategy, it isn’t bad. But what kind of aqua-attack craft should one bring? That’s a good question, and it’s one where the Yabarn made a huge mistake.
Putting together a surface or subsurface fleet is a big chore. Hydrofoils are fast, but they can’t handle rough surf. Same goes for hovercraft. The Yabarn made the worst decision possible. They were going to bring ships that were basically aircraft; they just hovered several meters above the surface of the ocean. If they can fly, keep them at higher altitudes; they can spot more targets from up there. It takes energy to hover above the surface of the water. To float, all a craft has to do is displace more water than it weighs.
I’ll say it until you get tired of hearing it. Hovering craft are easy targets, and they use up energy just standing in one place, energy that could be used for attack or defense. It may seem primitive to use a surface sea fleet, but get over it. Flotation works. So does the wheel.
A large part of the proposed Yabarn invasion fleet was designed to fly, float, dive, and were capable of spaceflight. As much as I applaud the engineering that went into these ships, they were the furthest thing from practical. The open ocean makes a lousy runway. The same choppy surf that makes hovercraft and hydrofoils impractical also makes landing and taking off from water tricky. As for dive capabilities, it’s not the hull integrity or even the shape of the craft that’s a problem. The challenge is that it requires a totally different type of propulsion below the water than when the craft is flying through the atmosphere. Designing a ship that has a drive system that can do both, and still have enough room for shields, weapons, equipment, and – oh, yeah, pilots – is a hassle. And from the plans, I saw these craft could go just about anywhere, but they had so few weapons and such a small crew there wasn’t much they could do once they got there. To top it off, the cost of constructing these craft was way out of proportion to their use on the battlefield. War isn’t about buying fancy toys.
To do it right, you want subsurface craft that resemble their terran counterparts in a lot of ways. They should basically be mechanical fish that rise or sink depending on manipulating their buoyancy. The advantage you’ll have is in better propulsion, handling, and sensors.
Weapons, however, will be very similar. Directed sonic attacks are a possibility. Electricity can be generated in large quantities. The problem is, when you’re submerged, there’s no way to get the charge to go where you want; it’s going to go everywhere at once. Because of water’s distorting effects on directed energy, both sides will be mostly using projectiles or torpedoes.
Surface combat will be at a distance. Even Earth has realized this. Most of their naval encounters now take place beyond the horizon, using long-range missiles and fighter/bombers launched from carrier vessels. The main advantages we have come in the form of shields that render these attacks harmless. The Yabaran realized this, too, and were one of the few invasion forces that planned to use long distance weapons. Though for some reason these weapons packed less punch than the ballistic missiles Earth was using at the time.
You will be involved in some form of naval action on the planet whether you like it or not. The important thing is to treat this like any other battle. The object is to win, not impress the enemy with hovering spacecraft or submarines that fly. If you want to impress your enemy, beat them. A victory always gets attention.
I hear a lot of groans. I know, you have already blown your budgets. You need millions of ground troops, and now you have to worry about a sea fleet. Planetary invasions aren’t cheap. If this is a problem, you might want to try something less taxing.