Easy way to reduce rolling on bilge-keeler?

I've been restoring a beautiful Cruiser Kits Santa Barbara 32. She's a plywood boat with a fibreglass skin. The bilge keels have hefty cast iron plates on them, but due to the rounded hull profile, she has a tendency to roll, particularly when the swell is at 90º to the hull. She could also probably do with a bit more ballast – although she weighs five tons, she has a tendency for the bows to be blown off course when sailing into the wind at low speeds.

However, my main issue is the roll. Can anyone think of a relatively easy and inexpensive way to reduce this? One idea that occurred to me is to bolt a steel or cast iron T-shaped fin along part of the centre-line of the hull, effectively creating a triple-keeler. (The T being fitted to the hull with a series of through bolts – fairly straightforward with a plywood hull.) If steel it could be glassed in to prevent corrosion. Cast iron would be better but is pricey and getting one cast to fit might be tricky.

Small wings on the bottom of the bilge plates was another idea, but they would be prone to snagging lines and nets. Or maybe bolting some cast-iron extensions onto the bottom of the existing plates, to make them deeper?

I must stress I'm a boat owner, not a designer, so if these ideas are bonkers, bear with me! I'm just looking for some practical advice. Obviously buying a different boat is one option, but she's been nicely finished and has a lovely interior. I've also fitted a new engine, so if I can make a relatively simple mod that would help with this issue, that would be great. Thanks

 

Are the bilge keels heve been modified ? At third pictures they looks different.

 

Hi Montero. The guy who built her added a hefty cast iron plate to each of the steel bilge keels to improve the righting. She does right well but I just want to damp down that initial roll.

 

Hi Richard, nice boat and restoration. Have you considered Flopper Stoppers, which work when stationary, not while underway ? For directional drift when pointing, you could try a slightly smaller jib / foresail, or tilt the mast rearward a bit, or a larger area on your main sail. The base of your mast is well forward of your keels, so it will have a natural tendency to want to go to leeward. You have a good sized rudder to steer back to course, but your sail setup centre of effort may be too far forward, by design. A smaller jib, or or use your stay sail more often, may make a difference to pointing.

 

Hi, and thanks for you kind words. I've seen diagrams of Flopper Stoppers in Practical Boat Owner, and may well rig something like that for anchoring. My bigger concern is roll under way. I haven't had the chance to sail the boat as much as I would like, due to issues with the old engine. However sailing from the Exe down to Dartmouth this autumn with an easterly swell was very rolly! Admittedly I was keeping fairly close to shore. I want to do a Round Britain in a couple of years, probably single-handed (but very leisurely - I'm 67), and need to know the boat will cope with potentially difficult waters – lots of chop and swell and no doubt my fair share of confused seas. I sailed to N. Ireland in my old Moody 33, so I know what conditions can be like, but that thing was built like a tank. Unfortunately I had to sell her due to financial issues during the lockdowns.

Your point about the sail set-up is fascinating. This is exactly the kind of technical info I just wouldn't know. As it happens there doesn't seem to be a full-size genoa on the boat, so the one I'm using is not particularly big – it stops well short of the top of the forestay. I could try a staysail, as I have an inner forestay. She sails well upwind in stiffer breezes, especially with the mizzen rigged, and points better than I expected, though strong gusts do tend to push the bow round. She has a fine point of entry, which probably doesn't help. (I've even considered making that slightly steeper with a little hardwood and few layers of fibreglass – one of the benefits of a plywood boat is you can muck around with it a little.) Maybe I should use the mizzen more, either with the genoa or the main – what do you think? I've never had a ketch before – something of a learning curve.

I think she could definitely do with a bit more ballast – do you think adding a bit more cast iron to those bilge plates would help with both issues? Sorry, I realise there's probably too much information here!

Thanks, Richard

 

If the boat has too much weater helm and rounds up, the mizzen would be better lowered. Does the boat roll too much on a reach? Have you considered if carrying more sail area and keeping the boat heeled would help? There are points of sail that will make a boat roll. You really have options. Firstly, you can change course slightly. Secondly, you can be stubborn (like some of us) and soldier on; stiff upper lip and all that. Other options like hull and ballast modifications are not likely to make it better.
I am somewhat confuse though. You say the boat is difficult to steer on a stiff breeze when sailing upwind slowly. Can you hoist more sail? Also, to make sure, you are sailing and not motoring with beam seas, are you?

 

Ya, what's up with those twin keels in the third picture?
Looks like excessive roll is not new to this hull...

 

I was assuming this means she is forced to the lee, or maybe as gonzo suggests, is she rounding up instead ? If blown to the lee, set less foresail, or try the mizzen, if rounding up, set less sail area to the rear, and more at the bow. The mizzen may be there to balance it better, but more work single handed. Maybe you are pointing too high, and almost stalling, so going slower, and the rudder is not so effective with less flow over it. Maybe try pointing off the wind a few degrees more than usual, getting more hull speed, more effective rudder, and with the wind load setting a more permanent mast heel angle, riding more on the lee chine, then the windward side of the hull will more out of the water, and not causing so much roll. The hull shape may prefer running well heeled over in a beam swell. With the extra ballast plates added, more than its design, you shouldn't need any more.
What do other owners have to say about it, or is its designer still available to ask questions to ?

 

Extra weight has already been added to the existing keels. Was the internal structure beefed up and larger bolts fitted? I would consider putting any extra ballast under the sole, rather than loading up keels never designed for it.

All boats roll to some degree, it will obviously feel a LOT different to your old Moody, but it is not to say the boat is fundamentally flawed.

I had lived aboard an old plywood, single chine, Waterwitch ketch for some years, a similar hull shape but with central iron ballast keel and steel plates. It really need the mizzen to sail well, not all ketches are equal on that point.

 

First of all you should store everything in the aft, and even in the corridor or passage of the boat over the bilge to avoid that pendular momentum, weight distribution is crucial for rolling , besides hull design and keels and masts span

Some ships and some classic sailboats use unballasted bilge fins for stability





These type of unballasted bilge fins can be used for beaching using a third central keel to hold the weight like some expedition centreboards

 

This post shows complete ignorance of physics and offshore sailing.

 

You're quite right. By pure chance I met a guy who knew the guy who built this boat (now sadly passed away). He went on its maiden voyage, and found she was very light, heeled over too easily and didn't recover so well. So the builder added those two hefty cast-iron plates and lead ballast under the floor, internally.

This improved handling dramatically, so I was told. She does now right quickly when knocked sideways by swell or wash from motorboats, but that initial roll is too easy and you can then get a pendulum effect. Hence my idea of adding a third keel – used on one or two British boats from the 1960s-70s – which would add extra ballast and maybe extra resistance to rolling. But it could prove quite an expensive modification, even on a plywood hull, I guess.

 

Actually she is not rounding up so much as the bow being blown to leeward by gusts, when sailing to windward. The rolling I experienced was motor-sailing in light airs on a beam reach, with the swell at 90º to the hull – you would obviously expecting a little rolling, but this was quite pronounced. Maybe it's just very different from my old Moody, which was very beamy and so had much better form stability.

I had a great sail on her a few days previously with everything up – small genoa, main and mizzen – sailing into the swell. She went over onto the chine and stayed there, and felt very comfortable. I haven't had the chance to do any downwind sailing unfortunately. I've been heading west this season, and as you know, the prevailing winds in the UK are south-westerlies.

 

I don't think any additional beefing up was done, but she is very solidly built, with lots of stringers and very thick ply. There was no sign of any cracks or movement around the bilge plates when I inspected her last spring. However maybe adding even more ballast to the keels is not such a good idea! I have added some more lead ballast under the sole to balance her, as the new Beta engine was a lot lighter than the Bukh, and she was nose-down. I can add more, but lead is obviously not cheap. What do you think of adding a centre keel, if it could be done reasonably cheaply? Do you think it would help damp that tendency to roll?

 

That's really interesting. Do you think these would be more effective in reducing roll than adding a single, unballasted central keel?