vanes, sails, gyros, fins...what about water tanks?

[eseyoung]

I have been following the discussions about stabilization methods. seems like everyone has a favorite and they all have advantages and disadvantages. I have not seen mention of water filled ballast tanks. I know that they are mentioned briefly in Beebe's book. Although if i remember correctly the mention is made by a revising author not Beebe himself. Also if i remember correctly, they work well and are move common of fishing vessels less common on yachts.

So why is this? seems like there would be some very difficult math to get it right but when you did it would be basically maintenance free. non parasitic on the propulsion and electric system. Am i missing something? Can anyone fill in my knowledge gaps?

For anyone who is unfamiliar, as i understand, these are essentially water filled tubes with baffles that are secured above a boat's center of gravity. As the boat begins to roll they baffles hold the water on the on the high side of the boat long enough to suppress the roll.

 

[psneeld]

I have been following the discussions about stabilization methods. seems like everyone has a favorite and they all have advantages and disadvantages. I have not seen mention of water filled ballast tanks. I know that they are mentioned briefly in Beebe's book. Although if i remember correctly the mention is made by a revising author not Beebe himself. Also if i remember correctly, they work well and are move common of fishing vessels less common on yachts.

So why is this? seems like there would be some very difficult math to get it right but when you did it would be basically maintenance free. non parasitic on the propulsion and electric system. Am i missing something? Can anyone fill in my knowledge gaps?

For anyone who is unfamiliar, as i understand, these are essentially water filled tubes with baffles that are secured above a boat's center of gravity. As the boat begins to roll they baffles hold the water on the on the high side of the boat long enough to suppress the roll.

This was addressed months ago yet I don't remember the details well enough. RickB had some good links if I remember.

I just know that water ballast is pretty tricky and hard to do on smaller trawlers....otherwise I would be fitting my tanks as we post.

 

[Tidahapah]

Flume tanks are very good if designed and positioned correctly.
Major problem for smaller cruisers is the space they require and pump out capacity required to dump in a hurry.
Cheers
Benn

 

[FF]

>Ballast tank

Am i missing something? Can anyone fill in my knowledge gaps? <

Usually there too small to bother.

We built our 90 /90 ( 33ft LOA) with 105G of water tank on either side , and a nice Edison Bronze 2 inch pump to move the FW. Pump before tacking and gravity helps move the water.

Fine if 200g is stowed for the Bahamas , or to blow all the water after storage , or if better water comes along.

But the weight of full on one side and empty on the other was hardly noticable.

The boat has a 40% ballast ratio, 7000lbs if keel , so a tiny change in heeling is hard to measure or feel.

Water tanks take up volume which on a small boat is a loss of space when they are installed winged out to increase the leverage.

A ballast tank could reduce heeling under a large press of sail, but would do nothing for the roll that motorboats suffer from.

 

[rwidman]

......I have not seen mention of water filled ballast tanks. ........ .

Some of the boats used for wakeboarding and such have water filled ballast tanks to modify the shape of the wake for better wakeboarding. They are adjustable by pumping water in or out.

If you think you really need ballast and don't need to change the weight once it's installed, water is not the best choice because it doesn't weigh much in water. Lead, sand, concrete, etc. provide much more weight in a smaller space.

 

[psneeld]

I have been following the discussions about stabilization methods. seems like everyone has a favorite and they all have advantages and disadvantages. I have not seen mention of water filled ballast tanks. I know that they are mentioned briefly in Beebe's book. Although if i remember correctly the mention is made by a revising author not Beebe himself. Also if i remember correctly, they work well and are move common of fishing vessels less common on yachts.

So why is this? seems like there would be some very difficult math to get it right but when you did it would be basically maintenance free. non parasitic on the propulsion and electric system. Am i missing something? Can anyone fill in my knowledge gaps?

For anyone who is unfamiliar, as i understand, these are essentially water filled tubes with baffles that are secured above a boat's center of gravity. As the boat begins to roll they baffles hold the water on the on the high side of the boat long enough to suppress the roll.[/QUOTE]


Can't be fixed and resist rolling....

 

[eseyoung]

Some of the boats used for wakeboarding and such have water filled ballast tanks to modify the shape of the wake for better wakeboarding. They are adjustable by pumping water in or out.

If you think you really need ballast and don't need to change the weight once it's installed, water is not the best choice because it doesn't weigh much in water. Lead, sand, concrete, etc. provide much more weight in a smaller space.

Perhaps i should have called them stabilization tanks or flume tanks. The purpose isn't to make the vessel ride lower in the water like ballast. the purpose is to stabilize roll.

 

[eseyoung]

I have been following the discussions about stabilization methods. seems like everyone has a favorite and they all have advantages and disadvantages. I have not seen mention of water filled ballast tanks. I know that they are mentioned briefly in Beebe's book. Although if i remember correctly the mention is made by a revising author not Beebe himself. Also if i remember correctly, they work well and are move common of fishing vessels less common on yachts.

So why is this? seems like there would be some very difficult math to get it right but when you did it would be basically maintenance free. non parasitic on the propulsion and electric system. Am i missing something? Can anyone fill in my knowledge gaps?

For anyone who is unfamiliar, as i understand, these are essentially water filled tubes with baffles that are secured above a boat's center of gravity. As the boat begins to roll they baffles hold the water on the on the high side of the boat long enough to suppress the roll.[/QUOTE]


Can't be fixed and resist rolling....

The tank (tube?) is fixed in place. the water (maybe other liquid) inside is what moves to prevent roll.

here is a link http://www.hoppe-marine.com/sites/hoppe-bmt.de/files/editorship/downloads/FLUME%20Stabilization%20System.pdf

 

[psneeld]

I know as I posted earlier...if I thought it worked well...I would be trying it on my boat. I quoted and highlighted for those who may not understand what you are trying to accomplish.

I was stationed aboard WWII class icebreakers that tried to use the water ballast technology and even assisted it with massive pumps...really didn't work for them either to reduce rolling...it wasn't tried on the more modern polar class breakers.

They DID work to INDUCE rolling when we would get stuck up on the ice and wanted to wriggle back off...

 

[bshanafelt]

try this link:

Flume Tank Stabilizers


I know of one gent who had a custom tank fitted on the pilothouse roof on a 50+ foot Roughwater, with great success. Crossed Oceans and found it absolutely effective both underway and at rest.

 

[psneeld]

I'm gald it worked for him...wonder how much weight/gallons could do the job and still not overpower the pilothouse structure.

I really have to wonder if they were so great...we would see more of them...I personally have never seen one..... even on hundreds of commercial steel vessels that could certainly benefit from them PLUS have the structural integrity to mount reasonably small ones.

 

[Phil Fill]

The best retro fit to an existing boat I know of is an ART, anti rolling tank. The tanks is actually on top of the roof, not the bilge. The tanks is a square box, with baffles that time/restrict the water back and forth to counter the roll. the Art has a large emergency 5” plug incase the tanks has to be emptied quickly. A sister 58 ft RW crossed the pacific with an ART. If you are interest I can email you some pictures and maybe a site if its still up.

First I am going to added passive bilge keels, then either paravanes or might try building an ART. I have the drawing for the ART of the 58 ft RW that is mounted on the pilot house roof. 10 ft long, 3 ft wide and 1 ft tall, being its up high it does not need that much weight. However as the fuel/supplies were used water/weight has to be added.

There are two types of stabilization, Passive and Active. Passive is blast, bilge keels, rolling chalks, keel plats, steadying sail. Active paravanes, hydraulic/pneumatic stabilizers and water flumes/tanks. I prefer passive because they are part of the boat and can/does change the stability of the boat where as active does not change the boats stability but improves the right. If the Active fails, then you left with the boats actual stability. If a long range boat requires active stabilizers then to me it not a long range boats as the boats does have the stability.

The 58 ft RW was designed by Ed Monk Sr and has good stability with out stabilizers. Stabilizer were not common back in the 60, 70, 80’s. The 58 ft fully loaded, fuel water, 5 tons, is very stable but empty it does tend to roll a bit. Personal I think active is a crutch/cure all for boat that do not have very good stability.

 

[psneeld]

I made a good friend when he hired me to move his boat because his normal captain refused to run the 55 foot Viking motoryacht without the stabilizers working. They sat in port for several days and the captain and crew suggested just hire a local guy after the weather subsides in a few more days...as letting a $450/day crew sit didn't make sense.

Passive sure is nice...but usually never as efficient...but a lot better if your active system breaks!

 

[dannc]

BeBee discusses both anti roll tanks(ART)which fit on the pilot house and bilge/fin keels. He mentions a study that found that bilge keels can reduce roll by 15-23 degrees in 10 foot seas and 13 to 18 degrees in seven foot seas. Design is important to get a positive result. If done wrong, you can have problems.

The anti roll tank(ART) on one boat kept most rolls to 5 degrees with some to 10. There was not information on the sea conditions though it seems they went to Hawaii. The worst roll was 30 degrees when hit by a breaking wave which implies the seas were not flat.

The ART reminds me of the sway dampers that are being installed on the top of some sky scrapers to minimize sway. Bebee does talk about the cons of ARTs and that there needs to be a way to dump the water quickly from the ART. If done right it seems like a simple KISS solution to minimize roll, better than paravanes but the thick is getting the correct design and installation. I would guess the water in the ART would provide decent insulation from the sun when in the tropics.

Later,
Dan

 

[nwboater]

Check out this video to see flume chamber in action:

 

[psneeld]

Nice magic trick...I saw a magician do similar tricks...now show me an actual 50 foot trawler in something other than perfect beam seas with pitch as well as roll...etc..etc...plus how much weight is necessary for a flume tank to work?....
Can the average trwler sustain the added weight/engineering?

I REALLY want to believe...I want a system for my bat...but why aren't they out there and much more common?????

 

[FF]

.I want a system for my bat...but why aren't they out there and much more common?????

COST and usefulness. So few boats go our in blue water , so few are built to handle ocean conditions due to the cost and other compromises ,.

I have designed , on paper, a system with a wide centerboard trunk.with a CB that could be made pivot to take an angle of attack .

With very little power the board could be driven to slow roll.

Advantage, is its lifted for no drag and will not hole the boat should the boat run aground .Should help when anchored .

Not been built, YET!

I have not copyrighted the idea of a powered roll damping CB so its up for grabs for anyone that wants to advance the art of cruising in comfort.

 

[Phil Fill]

I think an ART is the best retro fit solution as far as flumes/tanks go but there is not very much information on them. There is no pump it’s a rectangle box with baffles to time the flow of the water back and forth. I have a ½” technical document by Virginia Polytechnic Institute on ART, the owner of the Swan Song 58 RW used. Anyway it is way too complicated for my non tech brain. Several years ago I start building an ART. The prototype has adjustable baffles so the openings could be changed/moved. If you want copy email me.

For those of you that do not know the difference of rolling chalks and bill keels, rolling chalks are usually the full length of the water line NOT very wide/tall and there may be multi rows, and bilge keels are shorter but wider/taller. As far as stability they basically do the same thing but rolling chalks to not help prevent the boat from rolling over. Think of bilge keels as fixed fin stabilizers with a protect frame around them filled in which some boats have.

I have also looked at adding sails to the Eagle to make it a motor sail as another 58 RW was converted to increase range. More ballast would be needed, and maybe paravanes? But sails would only be added the if more than 2,000 mile range is needed. I love Tadahapah timber boat. Below is a 58 rw converted.

 

[psneeld]

I think an ART is the best retro fit solution as far as flumes/tanks go but there is not very much information on them. There is no pump it’s a rectangle box with baffles to time the flow of the water back and forth. I have a ½” technical document by Virginia Polytechnic Institute on ART, the owner of the Swan Song 58 RW used. Anyway it is way too complicated for my non tech brain. Several years ago I start building an ART. The prototype has adjustable baffles so the openings could be changed/moved. If you want copy email me.

For those of you that do not know the difference of rolling chalks and bill keels, rolling chalks are usually the full length of the water line NOT very wide/tall and there may be multi rows, and bilge keels are shorter but wider/taller. As far as stability they basically do the same thing but rolling chalks to not help prevent the boat from rolling over. Think of bilge keels as fixed fin stabilizers with a protect frame around them filled in which some boats have.

I have also looked at adding sails to the Eagle to make it a motor sail as another 58 RW was converted to increase range. More ballast would be needed, and maybe paravanes? But sails would only be added the if more than 2,000 mile range is needed. I love Tadahapah timber boat. Below is a 58 rw converted.

very simply...can you post how many gallons are needed?

 

[Tad Roberts]

The numbers I have on the Swan Song (Roughwater 58) flume tank designed by Don Bass of Saint Johns, Newfoundland.

Tank dimensions, 12' long, 4' wide, 16" high. Five "T" shaped baffles 18" from either end. Tank weight 250 pounds, 1550 pounds of water, approximately 6.5" full.......

 

[psneeld]

Thanks...

 

[Phil Fill]

The numbers I have on the Swan Song (Roughwater 54) flume tank designed by Don Bass of Saint Johns, Newfoundland.

Tank dimensions, 12' long, 4' wide, 16" high. Five "T" shaped baffles 18" from either end. Tank weight 250 pounds, 1550 pounds of water, approximately 6.5" full.......

Yup that it!

It was original sold as 58 Roughwater offshore Trawler.

 

[psneeld]

Almost 2000 pounds in the superstructure eliminates a lot of trawler sizes most of us have....

 

[Tad Roberts]

Almost 2000 pounds in the superstructure eliminates a lot of trawler sizes most of us have....

That tank (and any others properly designed) was carefully tuned to the size and roll character of the particular boat. Smaller boat = smaller tank....less weight required as rolling energy is lower.

 

[psneeld]

That tank (and any others properly designed) was carefully tuned to the size and roll character of the particular boat. Smaller boat = smaller tank....less weight required as rolling energy is lower.

I know...but Smaller boat = smaller tank only to a point...every boat would have to be measured and a specific tank for every model...unless plain old overkill design is used and then I'm sure weight would be still an issue for a lot of production boats...especially fiberglass ones and even more so Taiwan T's that just have a skin of glass over some barely structural plywood.

And then I guess adjustment must be made on long cruises for consumable consumption?...and where they are stored?

If I really thought it would be pretty easy and practical...I definitely would pursue one.

 

[Tad Roberts]

I was thinking on a smaller boat you could experiment with lengths of PVC pipe, say 8".....First try two, then three, etc. Make the baffles (about 18" from the ends) of wood or plastic, glued in or screw fasten from the outside (goop the holes). Cut pipe to length and cap the ends so they fit inside the flying bridge. Chock them they can't move, glue a small (say 1") nipple in the top and half fill (or more) with water. Drill a vent in that filler pipe.

Go find some chop and lay sideways in it.......

Actually the rolling of smallish (35'-40') cruisers, especially those with hard chines, will (I believe) be too fast to work well with a flume tank. The tank did work (it's subjective) on Swan Song because it's a larger boat with a slow rolling period.

 

[psneeld]

I was thinking on a smaller boat you could experiment with lengths of PVC pipe, say 8".....First try two, then three, etc. Make the baffles (about 18" from the ends) of wood or plastic, glued in or screw fasten from the outside (goop the holes). Cut pipe to length and cap the ends so they fit inside the flying bridge. Chock them they can't move, glue a small (say 1") nipple in the top and half fill (or more) with water. Drill a vent in that filler pipe.

Go find some chop and lay sideways in it.......

Actually the rolling of smallish (35'-40') cruisers, especially those with hard chines, will (I believe) be too fast to work well with a flume tank. The tank did work (it's subjective) on Swan Song because it's a larger boat with a slow rolling period.

Thanks...I was thinking the same about my 34 LWL/40 footer with hard chines...not sure what will help...

But this has got me thinking...I need some weight aft and could use a long step up onto the after house...maybe a "U" shaped tank around the back of the after house and partly forward along the sides may help...not worried about structure there...but not very high either.

If you saw the rot in my interior teak ply...you'd be scared of adding weight to the flybridge too!!!

 

[BruceK]

Not sure if this applies or helps, some modern racing sailboats have water tanks either side and pump the water to the weather side tank as ballast, reversing the procedure with each upwind tack. I assume downwind they equalize. Some have canting bulb fin keels used to similar effect.
Requires running an engine 24/7,which somehow defeats the purpose. Canting keels have been known to get stuck.

 

[Defever]

In the floor of the vee berth is a water tank. I don't know what is used for because I have water tanks for house water. Could it be it used for ballast?

 

[psneeld]

ballast and anti-rolling are two different animals....one is usually permanent or at least a tank and its weight stays in one place...anti-rolling is just that..it moves to counter rolling...much faster than a sailboat uses to offset heeling...

that's about as simple as I can explain it...