Ballast bar on steel keel?

[LeoKa]

A long time to stop rolling says there isn't much roll damping, which definitely isn't good for comfort. But for determining if it should have more ballast you want to time the roll from when one side rises through a full cycle back to the same point. You're aiming for a roll period in seconds fairly close to the beam in meters.

OK, I did it again. A full cycle was 6.66 seconds. Not scientific, but close.
The boat is 54' long, which is about 18 meters.
Perhaps the mooring lines shortened the period a bit, but not much.
The waterline is 46'=14m.

 

[rslifkin]

OK, I did it again. A full cycle was 6.66 seconds. Not scientific, but close.
The boat is 54' long, which is about 18 meters.
Perhaps the mooring lines shortened the period a bit, but not much.

What's the beam of the boat? Being a sailboat hull I'm guessing it's in the 15 foot range?

 

[LeoKa]

What's the beam of the boat? Being a sailboat hull I'm guessing it's in the 15 foot range?

14.2'=4.32m

 

[rslifkin]

Ok. That's definitely a pretty slow roll period, so I think you're on the right track with wanting to add some more ballast. It may not be the entire solution to getting good, pleasant roll behavior, but it should help some and will almost certainly make the boat safer from a stability perspective.

 

[LeoKa]

Ok. That's definitely a pretty slow roll period, so I think you're on the right track with wanting to add some more ballast. It may not be the entire solution to getting good, pleasant roll behavior, but it should help some and will almost certainly make the boat safer from a stability perspective.

Thanks for clearing this out for me. It certainly helps with planning and understanding my boat.

 

[MOJO]

Might want to look into adding bilge keels. They will do a lot more to slow/control roll than adding weight to the keel. Paravanes on MOJO work great. Deploying them is easy. They're stored in brackets on the transom. Just attach the cables, lower the poles and toss the vanes overboard. But, retrieving them requires a little bit of manhandling... Bilge keels work somewhat like paravanes in that they slow the roll period to get it out of sync with the seas. Depending on access to the hull inside, they can be fairly easily welded on. Definitely recommend a naval architect get involved so you only make the fix once!

 

[Judy at JWY]

There have been numerous posters who have recommended hiring a naval architect. If you choose to heed their advice, I highly recommend Marius Lengkeek of Lengkeek Vessel Engineering.

 

[Portage_Bay]

LeoKa,

I want to jump back in here and mention the difference between stability and comfort. Stability with respect to rolling is the boat's ability to right itself. It is primarily the relationship between hull form, center buoyancy and center of gravity. Hull form and center of buoyancy are not readily changeable in a built boat. Center of gravity is. Your idea to add weight to the keel and or the ballast bags change the center of gravity. Other changes you can make are to move things lower before open water passages. You said on a recent transit things up top shifted. Of course you know now to secure them better. Consider also moving them lower. Every little bit will help.

As for comfort bilge keels (rolling chocks), steadying sails and paravanes will increase comfort by dampening the roll. They will not increase stability from a safety standpoint. Some because weight is being added high up will reduce stability. Some say that dampening the roll may reduce the boat's ability to right itself. I'm not sure about that but it seems to make sense.

Rslifkin has discussed with you conducting a dockside rolling test to assess total righting energy. It seems your boat is lacking for open water transit. Read up on it and conduct the test again to get good #s.

Several have suggested engaging a naval architect. I strongly support that. All indications from your posts suggest you have a very tender boat. Easily upset and not so able to right itself. This could be a very serious issue if you plan open water transits.

Apologies if I've covered things you already know.

 

[Benthic2]

I would be concerned about the drift of this thread. It started with how to add ballast down low and evolved into possibly adding a steadying sail. IF the boat is underballasted ( I do not think that has been confirmed ) wouldn't adding a mast and applying a force up high be a dangerous step ?

My other thought that is if this was built as a sailboat hull it should have been ballasted sufficiently for that use. If the OP is using it as a power boat it should be way over ballasted so whatever his goal, I am not sure adding ballast is the way to acheive it.

And now for the part that everyone else is too kind to bring up:

If this is all an attempt to keep cabinet contents contained, perhaps all that is needed is a little cabin tidy-up and door latches. I hope I don't hurt anyone's feelings here, but the after action analysis done by the captain might be biased here. It is a lot easier to say the boat is to blame than the captain. I am not saying the OP is at fault, just suggesting that as much analysis that has gone into the boat should also be applied to the captain. Were conditions too rough ? Were things just not stowed propperly ? Were the seas approached at the wrong angle, etc ?

As humbling as it sometimes is, the best corrective action here may be better judgement by the captain.

 

[LeoKa]

Were conditions too rough ? Were things just not stowed propperly ? Were the seas approached at the wrong angle, etc ?
.

Please, read back on this thread. I have admitted already that things were not secured enough for 22 degree rolls. Yes, I am guilty.

Also, the boat does have ballast, just maybe not enough. Steadying sail, more ballast, bilge keel, are all just ideas to make things smoother. I am not chasing perfection.

 

[LeoKa]

LeoKa,
Center of gravity is. Your idea to add weight to the keel and or the ballast bags change the center of gravity. Other changes you can make are to move things lower before open water passages.

Yes, this is one of the things I am planning for. Mistakes made, lessons learned.

 

[LeoKa]

Might want to look into adding bilge keels.
Definitely recommend a naval architect get involved so you only make the fix once!

My first choice was bilge keel, as well. I am still working on the idea. I talked to a welder already who has done it before, so installing it will not be a problem. We have not talked about money, yet.

I agree, the best way to go is hire an architect. As I mentioned earlier, the architects who were involved so far, are not getting back to me. When time comes, I will certainly look for one in the area.

 

[dannc]

My first choice was bilge keel, as well. I am still working on the idea. I talked to a welder already who has done it before, so installing it will not be a problem. We have not talked about money, yet.

I agree, the best way to go is hire an architect. As I mentioned earlier, the architects who were involved so far, are not getting back to me. When time comes, I will certainly look for one in the area.

If you have not read this on Kasten's website, https://www.kastenmarine.com/roll_attenuation.htm it discusses bilge keels and other anti rolling strategies.

Kasten's website is a treasure trove of information.

 

[LeoKa]

If you have not read this on Kasten's website,.

Yes, I have. It was quoted here already, but I have seen the articles before. It is very valuable reading.

 

[LeoKa]

There have been numerous posters who have recommended hiring a naval architect. If you choose to heed their advice, I highly recommend Marius Lengkeek of Lengkeek Vessel Engineering.

Does he work remotely, or needs to see the boat out of the water, before any design?
I still have time to get this figure it out, but I want to start the ball rolling and see, if these is best option, how much does it costs to design a bilge keel plan, what does the welder need from an architect?
My problem is, I do not have any documentation about the modifications, or the original hull design of this boat. I am not sure how an architect can work on a plan without this data?

 

[Judy at JWY]

LeoKa -- I suggest you give Marius a call. I could call him and ask the questions, but I think it best for you to speak with him so you can answer his questions with appropriate details. I am quite sure Marius would be glad to have a gratis preliminary conversation about your needs.

Feel free to use my name. No, I don't get referral fees but if he's busy, a little name-dropping might prompt a faster response. Please give my regards.

 

[LeoKa]

LeoKa -- I suggest you give Marius a call. I could call him and ask the questions, but I think it best for you to speak with him so you can answer his questions with appropriate details.

That is one of the problems; I do not have the necessary data to approach a designer. Not yet. I am working it, but not getting replies from people who could have it. Once I do, I will contact him. Thanks.

 

[LeoKa]

Here is a good read about bilge keels:

https://www.brayyachtdesign.bc.ca/article_twinkeels.html

 

[LeoKa]

I was around the yard where the boat was stored and then modded and knew the guy that did a lot of the work, but it was a lot of years ago now. The original owner basically took a sailboat hull and overwhelmed it with a big steel house and a big diesel engine. The boat was really tender and would squat badly at speed. The next owner hired Howard Appolonio to try and come up with improvements. They basically added the bottom tank, a bunch of steel including that I-beam to try and get some stability and a big bustle to try and add volume aft to help the squat. I don't know how successful any of that was.
It seems now, as others have mentioned, that it'd be pretty easy to bolt on some weight to either side of the I-beam. Look at the space available, do some calcs to determine if you can do it out of steel if not cast some lead.

I went to the yacht sale/design shop a week ago, where Howard A. is listed as the founder. Unfortunately, Howard is not involved in things anymore and the gents at the office did not have any recollection of my boat's design corrections.
Yesterday, I've read the survey report back from 2008, when the description of the vessel included this:
' This is a 54' custom steel vessel that is a Bruce Robert's design for a motorsailer that was modified by Glen Freidhom to a pilothouse vessel.'
I have searched the mentioned name above, but I could not find anything about him. The B.R. web site has no phone number listed. Lots of plans to buy, but no address, no contact info.
I also called the previous owner, but he told me there was no modification during his ownership. He thought the first owner might not be around, since he was in his 70s, when the boat was sold in 2008.
So, I am stuck. I cannot find any data about this boat.
I hoped to have something for an architect, when I find one to design me a bilge keel solution.
It seems, I need to find someone in my area on the Columbia river, who could visit the boat, when it is out on the yard this summer.
Anyone can suggest a naval architect around Ilwaco, WA boatyard?

 

[Marco Flamingo]

It seems your boat is lacking for open water transit. Read up on it and conduct the test again to get good #s.

You can read up on it in naval architect David Gerr's book The Nature of Boats at page 109. As rslifkin points out, the test that you need is what's called a "roll time to beam" (RTB). You need a ratio of about 1. And "about 1," means really, really close to 1. Gerr says that .97 RTB is okay for a cruising sailboat for open ocean and 1.1 might be okay depending on usage. In fact, he states at page 116 "However, if you own an average powerboat with a roll time greater than 1.1 on the beam it would probably not be prudent to operate her in conditions that will roll her deeply; she could pass the point of no return." My boat has an RTB of .98 and is considered "snappy."

You state that your roll time is 6.66 seconds and your beam is 4.32 meters. That is an RTB of 1.54. And this is after a prior owner has already added lead, welded a steel beam on the keel, and added some kind of ballast tank? And you are contemplating open ocean cruising? Yikes.

Time to double-check your numbers on roll timing. Gerr talks about stopwatch timing in his 1992 book, but there is an easier way today. Download a free accelerometer app for your phone. Rock your boat and save the graph that the app creates. Then, you can look at the peaks and valleys over a longer period of time, say 60 seconds if the boat freely rocks that long. If you are correct and it really is 6.66 seconds, extreme surgery would be required. And by extreme, I mean like removing most of the superstructure. Even crazier, adding 2 meters of beam. Hopefully, you timed the roll period wrong.

 

[rslifkin]

And by extreme, I mean like removing most of the superstructure. Even crazier, adding 2 meters of beam. Hopefully, you timed the roll period wrong.

Or possibly making the keel deeper to increase the leverage arm for the ballast.

 

[Marco Flamingo]

The keel is already 7.4 feet deep according to the OP. I suppose that was measured, as the OP doesn't seem to have the original plans. Ted is no longer designing, but I've never heard of an NA that threw out old plans. Not sure original plans would show much other than what it was supposed to be. I'm sure he didn't figure on the vessel ever having a 9' draft in an attempt to address stability issues.

Probably hard to figure out where the original waterline was supposed to be. Sometimes a wily surveyor will notice that the original boot stripe has been moved over the years. A likely indication that she isn't floating like she should. A modified boot stripe can show floatation, trim, and overload conditions. Like if a vessel has a bigger engine than what was spec'd. That, combined with the over-sized superstructure (with it's extra drawers, cupboards full of stuff, solar panels, etc.,) would likely throw things way off. Presumably, the bigger engine was to get more speed out of a displacement hull, which didn't work of course and only caused her to squat. I can see Ted throwing up his arms and saying NO!

The added bustle to control stern squat is also concerning. Is it empty, i.e., full of air? It seems like that would create a big negative moment arm on the stern and tend to make the vessel uncomfortable (or dangerous) in a following sea. Is it full of water? Not sure what that would do. It might be difficult to get a NA to even make suggestions based on all the unknowns.

 

[Marco Flamingo]

I should also note that Dave Gerr runs through a discussion on how much alteration to a vessel's trim and flotation is safe, i.e., how far from the designed waterline can you safely deviate. After the normal NA maze of arithmetical formulas, he says that they tend to all lead to a basic figure. One percent of the designed waterline. OP say the waterline is 46 feet (552 inches). If my math is correct, that means the boat should be no more than 5.5 inches below the designed waterline (even if stability seemed okay). So there would be some value in getting the original plans. Especially if thinking about adding more weight.

Gerr also provides a formula for calculating how much weight it takes to lower your vessel one inch. For my little pocket trawler, it's 1,237 pounds. It might be nice to have that number for a vessel when thinking about adding weight.

 

[LeoKa]

Time to double-check your numbers on roll timing. Gerr talks about stopwatch timing in his 1992 book, but there is an easier way today. Download a free accelerometer app for your phone.

Thanks Marco.
I have the app. Once the rain stops, I will do the test.

 

[LeoKa]

The added bustle to control stern squat is also concerning. Is it empty, i.e., full of air? It seems like that would create a big negative moment arm on the stern and tend to make the vessel uncomfortable (or dangerous) in a following sea. Is it full of water? Not sure what that would do. It might be difficult to get a NA to even make suggestions based on all the unknowns.

All I have is a survey from 2008, when the boat was sold to the second owner.

The survey says; "it was BR sailboat design, but modified to pilothouse vessel. The modification included by removing the extended keel and adding a full superstructure.
Signs where 8' long rolling chocks have been removed port and starboard. I-beam was installed on forward portion of the keel. It has reportedly cruised to Alaska with no problems."
LWL 46'10", beam 14'3", draft 5'9", GDR 38 Net 30T, fuel 880g.

The fuel is now 1200 gallons. 400+400 each side and 200+200 in the keel tanks. So, something was changed. Notice that the draft is now 7.4 not 5.9 as it is in this survey.

The addition at the stern is an air-tank to my knowledge. It has a short pipe with valve on each side, but I have never opened it. I suspect it is full with air.

 

[LeoKa]

You state that your roll time is 6.66 seconds and your beam is 4.32 meters. That is an RTB of 1.54. And this is after a prior owner has already added lead, welded a steel beam on the keel, and added some kind of ballast tank? And you are contemplating open ocean cruising? Yikes.

It is possible that I did not do the test correctly. The app will possibly give me more accurate numbers.

I do not plan to cross the ocean. Only coastal cruising, which this boat has done already to Alaska.
I did the Puget Sound to Oregon trip, last year. I had following seas and it was not comfortable.

 

[SteveK]

I found this BRUCE ROBERTS OFFICIAL WEB SITE boat plans & kits for steel, aluminum, fiberglass, wood epoxy boats
and this boatdesigns@gmail.com
No idea if this is an active web page, but if it is, you may get some more info on your boat. There may have been many versions of the house and I could not find any that was the same as yours.

 

[LeoKa]

I found this BRUCE ROBERTS OFFICIAL WEB SITE boat plans & kits for steel, aluminum, fiberglass, wood epoxy boats

Yes, I did too. I wrote to them, but nobody replied.

 

[Marco Flamingo]

Oh, Bruce Roberts. I thought it was Ted Brewer. Bruce Roberts, Ted Brewer, Bob Perry, Nat Herresoff, doesn't matter. All would say "that is not my design."

More numbers that you might want/need in the future. When hauled on the sling, did you get the weight? I don't remember the last time I saw a haulout where the operator said that the travel lift scale worked, but maybe. The State of Washington has a guy that travels around to certify whether your butchershop scale is accurate to the 100th of an ounce, but not a travel lift within a ton. Bologna, one might say.

Actual "real world" beam at the waterline (using a plumb bob from the scum line when hauled) is usually different from what a survey or design drawing says, but it is the number used for stability calcs.

The accelerator app on a phone can also be used to find the actual CG. Set if for X and Y (pitch and roll) and start by putting it on the centerline on the cabin floor. By moving it fore and aft and raising it up and down (tedious), you can locate the spot where there is no acceleration (flat line) because the vessel is simply rotating around that point in space. Should be about 55% back on the waterline and who knows how much above the waterline.

 

[LeoKa]

Marco.

You are giving me more homework. I feel like I am in high-school. Lol
Either way, I like your suggestions. The more I learn about my boat, the better. It never hurts to increase my knowledge. Who knows, maybe there is a solution to improve the stability of my boat? Serious changes are not in my budget. I love the boat, but it is not worth it to spend 50-100K on it. It is a perfect live-aboard and I enjoy this home I have, but I do not plan to do any major alterations. I can play with ideas to a certain degree, but maybe there is a point, when I just give up and enjoy the boat as it is.

What is ' plumb bob '?

Once the weather clears here on Columbia river, I will do the tests.