SeaPhantom draws Batman looks, High-Speed Desires

Look how flat the water is in the picture. This will be an inland waterways boat only. Forget rough water

Hydro-foils actually work better in rough water than standard hulls. This is because the foils are underneath the waves instead of on top of them. I believe there are some large (car carrying) ferries around that are hydrofoils. Now will they be going 85nm/hr in 15-20 foot waves? I don't know but probably not however that depends on the height of the hull above the waves at speed. The article doesn't discuss this at all. I would guess that this boat could handle 4-6 foot waves simply because that those height waves are pretty common but that is still a guess based on some vague memories of what I think I've heard and read. Looks like another excuse to search the web for information on something I'm curious about, which I've done initially below.

This is a quote from the Boeing hydrofoil site:

"A 71-foot, 57-ton patrol gunboat, the Tucumcari, launched in 1967, was the first large hydrofoil to use waterjets instead of propellers. It could fly over the water at more than 55 mph in all kinds of weather."

Here is the link to Boeing page. http://www.boeing.com/history/products/jetfoil-hydrofoil.page

Foil boats can generally handle waves well, the US Navy for example has (had?) some fairly big ones that had some sort of "look ahead for waves" feature that made them excellent in fairly heavy weather. There was some film around in the 1980s of a Frigate sized ship going through some heavy weather with no problems at all. In fact the ship rode the sea better than a conventional ship of a similar size.

In an outright force 12 storm, I could imagine that the foils are not so good, but then normal boats and ships also have problems then too......

The foils reduce the need for huge engines and heavy fuel consumptions, by reducing the resistance that a hull has when displacing water, but not when skimming over it. Then air resistance becomes the new force to be reckoned with I guess!

It would be nice to learn more about this particular one....

Give me a break. Can you even begin to imagine a 15-20 ft boat doing 80kn in any kind of waves. Unless the foils are long enough stay in the water and keep the hull out of the water 100% of the time it will be a disaster. Why do you think the picture is taken in completely flat water?

If a frigate sized ship was practical and saved fuel, where is it?

Frigates don't grow on trees, financially or otherwise, I do not know whether the US Navy has finished testing or even come to any conclusions.

Planning a modern warship means that by the time the deisgn has hit the water, it is anything upto 10 years out of date.....normal business in this area.

I was just pointing out to you that you cannot simply dismiss foil boats and ships as simply as you seem to......just because you don't like they way they look, or its just a biased opinion or whatever. To use your own words, give the boats/ships a break!!

I hope some others who have actual knowledge, experience, facts and maybe a few good web addresses in this area come and say their piece, I have an open mind on this (on everything really!!)

I have not dismissed foil boats but 85kn passages in a small boat in big seas are very impractical. A boat weighing a few thousand lbs. going up the front or the back of a wave at 85 kn will cause the boat to be airborne and out of control after it passes the peak of the wave.

Where you get this:

"just because you don't like they way they look, or its just a biased opinion or whatever."

is beyond me. I never discussed how it looks.

I think actually the reverse is true about yourself...you like the way it looks and doing 85kn on the water sounds like fun to you and you don't care if 85kn in rough water is impractical in a small boat.

...I would have expected any normal person on water, to slow down to the speed needed when confronted with heavy seas....or any other hazard for that matter!

The same goes when driving a car - you might have a Ferarri that does 200MPH, but traffic, traffic lights etc etc etc dictate that your speed must be conversant with the conditions and the law!!

Have we not been doing that for a very long time, even since man built the first boat and put to sea? or put the first car on the road?

I just did not feel that it needed to be stated here again......of course what you propose is what a lunatic might just do, but he should not be driving anything larger than a Dinky toy in the first place, while bathing!!

I personally feel that certain facts in certain situations are (or should be!) completely self evident, obviously that is not the case always.....sorry to seem to be unfriendly but you had to have it stated in words it would appear......

I still wish you a great day and many more fun entries on CR4, the world's best Blog!!

Well excuuuuse me...

From the first response to this blog which was my response I said "

Look how flat the water is in the picture. This will be an inland waterways boat only. Forget rough water"

It was you who came back with this response:

"Foil boats can generally handle waves well, the US Navy for example has (had?) some fairly big ones that had some sort of "look ahead for waves" feature that made them excellent in fairly heavy weather."

This indicated your beliefs to be contrary to mine stated. So don't go trying to convince me that it would have been obvious to anybody when you are just trying to cover your own ass.

Do you always drive in circles?

The speed of anything must be passed according to the conditions, its as simple as that..... what the speed of this boat will be under any particular set of conditions will probably be better than a similar conventional boat....certainly not worse is my guess.

It would be interesting to see a true comparison.