A Mad Mulligan
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July 7th, 2008, 12:17 PM
Paging # juan, or anyone else who might know about these.
Have you heard anything about Swath hull boats? There are a couple out East I know and down in the States. I've been wondering if the effects are scalable and how effective the stabilization really is.
Any engineering buff care to put the thinkers on this thing?
Paging # juan, or anyone else who might know about these.
Have you heard anything about Swath hull boats? There are a couple out East I know and down in the States. I've been wondering if the effects are scalable and how effective the stabilization really is.
Any engineering buff care to put the thinkers on this thing?
Executive Member
Posts: 9,235
July 7th, 2008, 12:55 PM
I wish I could tell you something useful but my knowledge on this subject is very limited. I saw a picture a few years ago of a fairly large Swath design cat that was reportedly going 30 knots. The strange thing about it was that it was doing that speed without a deck angle of 45 or 50 degrees. It wasn't level by any means, but both hulls were in the water.
I wish I could tell you something useful but my knowledge on this subject is very limited. I saw a picture a few years ago of a fairly large Swath design cat that was reportedly going 30 knots. The strange thing about it was that it was doing that speed without a deck angle of 45 or 50 degrees. It wasn't level by any means, but both hulls were in the water.
A Mad Mulligan
Posts: 2,876
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July 7th, 2008, 02:40 PM
I like the thought of it and from what I've seen it's amazingly comfortable in ride, even in bigger seas. I saw a 60 footer for sale but I don't know if the extra expence would be worth it. The US military has one that does 60 knots.
I like the thought of it and from what I've seen it's amazingly comfortable in ride, even in bigger seas. I saw a 60 footer for sale but I don't know if the extra expence would be worth it. The US military has one that does 60 knots.
Executive Member
Posts: 9,235
July 8th, 2008, 08:53 AM
I've just done a bit of reading on the subject and it seems that SWATH designs are scalable in so far as the testing of several fairly large ship designs was carried out using small scale models. What is interesting is that these designs reduce not only resistance through the water but also reduce wave production. One of the things that helped kill the B.C. Ferry corp, "Fast Ferries" was the land erosion caused by the large waves produced by these boats. Here is a link that you have probably already seen. I found it very interesting.
http://www.rti.com/products/data_dis...O_SeaSLICE.pdf
I've just done a bit of reading on the subject and it seems that SWATH designs are scalable in so far as the testing of several fairly large ship designs was carried out using small scale models. What is interesting is that these designs reduce not only resistance through the water but also reduce wave production. One of the things that helped kill the B.C. Ferry corp, "Fast Ferries" was the land erosion caused by the large waves produced by these boats. Here is a link that you have probably already seen. I found it very interesting.
http://www.rti.com/products/data_dis...O_SeaSLICE.pdf
Les
Posts: 6,049
Location: 50 acres in Kootenays BC
Location: 50 acres in Kootenays BC
July 8th, 2008, 11:51 AM
That's kinda similar to the boats that start out with the hull entirely in the water and then as speed gets up the hull raises out of the water so the boat is riding on planes. Whatever happened to those boats? Think I read somewhere they had been clocked at over 40 knots.
That's kinda similar to the boats that start out with the hull entirely in the water and then as speed gets up the hull raises out of the water so the boat is riding on planes. Whatever happened to those boats? Think I read somewhere they had been clocked at over 40 knots.
Executive Member
Posts: 9,235
July 8th, 2008, 01:18 PM
Quoting L Gilbert
You are no doubt thinking of hydrofoils. Hydrofoil craft are probably not suited to B.C. coastal waters because of the piggish habits of our forrest industry, There are so many logs and deadheads in the water it is dangerous. I have seen a couple fiberglass boats get their bottom ripped off by running over a ten ton log at high speed.
That's kinda similar to the boats that start out with the hull entirely in the water and then as speed gets up the hull raises out of the water so the boat is riding on planes. Whatever happened to those boats? Think I read somewhere they had been clocked at over 40 knots.
Executive Member
Posts: 9,235
July 8th, 2008, 04:51 PM
The Bras d'or is the best remembered Canadian hydrofoil. She could do 63 knots (72 plus mph.)
http://www.foils.org/brasdorp.htm
The Bras d'or is the best remembered Canadian hydrofoil. She could do 63 knots (72 plus mph.)
http://www.foils.org/brasdorp.htm
A Mad Mulligan
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July 8th, 2008, 06:44 PM
Hey thanks for the link #juan. I have been looking that over actually.
Swath hull isn't quite the same as a hydrofoil as the swath hull rides below the surface where all the turmoil is. They can also have the ballast pumped out so they ride up on the surface and provide a very shallow draft. Nice for the Caribbean moorings.
Blue water passage isn't a problem with them either if you can manage the fuel. I wonder if using a gas generator to power electric engines would be feasible in the 60 foot range?
Hey thanks for the link #juan. I have been looking that over actually.
Swath hull isn't quite the same as a hydrofoil as the swath hull rides below the surface where all the turmoil is. They can also have the ballast pumped out so they ride up on the surface and provide a very shallow draft. Nice for the Caribbean moorings.
Blue water passage isn't a problem with them either if you can manage the fuel. I wonder if using a gas generator to power electric engines would be feasible in the 60 foot range?
A Mad Mulligan
Posts: 2,876
Videos: 4
Location: The Moonsine Cafe
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July 9th, 2008, 06:09 AM
Quoting Lineman
Oh yeah I read up on that. Sad story really. The inventor went from millionaire to pauper over this design. There was just a documentary on this subject and the way he ended up was quite tragic.
SWATH was invented by a Canadian I believe, but the idea never caught on in Canada. See wikipedia
Executive Member
Posts: 9,235
July 9th, 2008, 10:04 AM
I'd like to see someone try this on a smaller boat because with the fuel cost at the moment, it is very close to ruling out motor boating for any but the very rich. My last boat could hit 30 knots at a cost of thirty gallons of gas per hour. Takes the fun right out of it.
Quoting Unforgiven
I've always been a bit uncomfortable with gas engines on boats but it could be done. Have you any idea how much power you might be needing? I assume the power requirements would be something less than a planing hull of the same length. One problem with gas/electric or diesel/electric is the efficiency drop going from gas power to electrical, and then powering electric motors, but it would likely be cheaper than a specialized right angle gearboxes to drive the propellers. I don't know if you can buy something like that off the shelf or not but I'm sure they would be costly.
Hey thanks for the link #juan. I have been looking that over actually.
Swath hull isn't quite the same as a hydrofoil as the swath hull rides below the surface where all the turmoil is. They can also have the ballast pumped out so they ride up on the surface and provide a very shallow draft. Nice for the Caribbean moorings.
Blue water passage isn't a problem with them either if you can manage the fuel. I wonder if using a gas generator to power electric engines would be feasible in the 60 foot range?
Swath hull isn't quite the same as a hydrofoil as the swath hull rides below the surface where all the turmoil is. They can also have the ballast pumped out so they ride up on the surface and provide a very shallow draft. Nice for the Caribbean moorings.
Blue water passage isn't a problem with them either if you can manage the fuel. I wonder if using a gas generator to power electric engines would be feasible in the 60 foot range?
I'd like to see someone try this on a smaller boat because with the fuel cost at the moment, it is very close to ruling out motor boating for any but the very rich. My last boat could hit 30 knots at a cost of thirty gallons of gas per hour. Takes the fun right out of it.
No sparks please
Posts: 374
Location: Winnipeg, Manitoba
Location: Winnipeg, Manitoba
July 9th, 2008, 11:17 PM
Quoting Unforgiven
What channel was that on? I would like to see it if it ever comes on again.
Oh yeah I read up on that. Sad story really. The inventor went from millionaire to pauper over this design. There was just a documentary on this subject and the way he ended up was quite tragic.
