Centerboard Keels in Blue Water Vessels

[delmarrey]

Originally Posted by CarlF

Centerboard boats also typically use encapsulated ballast and therefor lack the single worst piece of engineering in modern sailboats - keel bolts. The loss of a keel can and does kill people, yet to save a few dollars most builders persist in using the wrong metal (stainless instead of bronze) to secure an extremely heavy object to too small a keel stub. Conventional practice uses no keying or other fiberglass reinforcement for the keel. Worse, there is rarely a telltale sign of a broken or corroded bolt. The only reliable way to check the keel bots is to drop the keel - if it's possible to dissemble the interior to reach all of the bolts. This expensive adventure always requires a boatyard - and a good one at that. If your boat has ever had a hard grounding or is more than ten years old -- and you've never dropped the keel - those bolts should worry you.

Actually one can buy monel keel bolts which will out last most boats out there. It comes down to $$$$ Aqualoy 22 is good stuff too! MarsKeel - Technology

I just recently rebuilt 4 cast iron valves for a drydock (2-24" & 2-18") 1 of which had a bronze stem. They were about 25 years old. The cast iron was heavely eroded away but the monel stem and seats were like new. The bronze was pitted a bit but again the monel seats were in great shape.

One of the first things I did when I got my boat was check which metal the keel bolts were and they are 316L. So, I'm not worried. Bronze would have probably sheared off by now.

[Steve Pope]

My Trismus's aft board is pivoted board, just a slightly smaller version of the main board. It tracks extremely well down wind, and can be used to balance the boat on other points of sail.

[Zednotzee]

Originally Posted by shadow

Don't forget the southerly yachts which is almost totally centerboard/lifting keel range of yachts... Excellent yachts and one that is on my very short list..

Paul & Sheryl Shard traded up from a Southerly 42 to a 48. Having covered a lot of mileage, transatlantic & Carribean, I'd say it's definitely blue water boat- opens up a lot of shallow anchorages too.

Distant Shores

[Sharkman]

Originally Posted by Sailndive345

Those sure are great testimonials in favor of these boats!

One of my favorite features that the Garcia offers is the stern daggerboard (just in front of the rudder) - so much so that I envisioned adapting something like that to my fiberglass boat Have you seen any such additions to Ovnis? From all I have heard, the daggerboard helps the Garcia track almost as if she has a long/full keel.

Fair winds!

Sailndive

Hi there

The OVNI differs from the Garcia in that it has a deeper rudder - the lower section swings down and locks in place. One way that gets past the difficulty of the boat drying out level. The Garcias (older models) all use a very shallow rudder blade and a daggerboard for trimming to achieve the same end. As far as I'm aware both boats go downwind very well, dag or no dag - ours certainly does. I spoke to a Garcia owner last year and we compared thoughts on this and it seemed to me that there was nothing in it. He did say that he used his dag upwind for balance, and with the small rudder blade that made sense. Both arrangements have their advantages - the OVNI has a full skeg and lower bearing and is massively strong, but has the complication of the hydraulics and extra maintenance for the bearing etc. The Garcia may trim better upwind, and its a very simple, strong set-up. Ultimately I reckon that downwind it has more to do with the ability to lift the plate up into the hull - the boat finds its own way downwind with no struggling at the wheel, and no chance of tripping on the keel.

Both Garcia and OVNI are going towards twin rudders in their latest bigger designs - this may have some advantages in terms of directional stability, but it's hardly less complicated, and I'd be a little bit more concerned about drying out. I reckon the older systems have a lot going for them, Garcia or OVNI.

Best wishes

[bitman]

Originally Posted by Zednotzee

Paul & Sheryl Shard traded up from a Southerly 42 to a 48. Having covered a lot of mileage, transatlantic & Carribean, I'd say it's definitely blue water boat- opens up a lot of shallow anchorages too.

Distant Shores

indeed and they are very happy with it so much that they traded it up to an southerly 48

they are on some travel channel (or buy their dvd's) so you can see why it so nice to have an swing keel for those places where fin keelers can come.

[jck339]

Shannon sells centerboard versions of their yachts. The lifting board contributes very little to the stability of the boat. I think the centerboard on the Shannon 43 weights 600 lbs and is retracted via a winch. It would also kick up in the event of a grounding, assuming motion was forward.

[fcallard]

My Clearwater 35 has a weighted swing keel (~3000#) which completely retracts from 5'11" draft to 1'10" draft. It is hauled via a winch-assisted block and tackle arrangement, but is lowered by gravity--like letting out a genoa. I asked the builder what would keep the keel from "falling up" in a capsize. His reply was that you ought to retract the keel in conditions that could cause the boat to turn turtle.

His logic? The keel could "trip" the boat coming down a wave, so you'd best retract it in these conditions. He asked, " Did you ever see a log capsize?"

The Clearwater 35 has about 5000# of lead ballast split about 50/50 between the very slack bilge and the leading edge of an elliptical keel, so that the boat is still well ballasted even when the keel is fully retracted. A conventional centerboard boat would have similar ballast considerations, but the Clearwater 35 differs in that there is no vestigal keel (like the Southerlys)and presents a smooth whaleback figure underwater when the keel is completely retracted.

So, it may make sense to retract a keel/centerboard when in conditions conducive to a capsize and thereby reduce the "tripping" moment. Food for thought!

[Stillraining]

Makes sense to me ..I will adopt the practice...Thanks

Great first post by the way...and Welcome Aboard..

[Jmolan]

I have a massive board and trunk. On a 34' boat It is 6 1/2 feet long. When it is down the boat really climbs to weather. And the motion is much better with the board down biting in steady water. After reading most of your excellent posts, I realize how lucky I am.
My board floats. After I winch it DOWN, I hold it down with a small (1/8") fuse line. If I hit somthing, it snaps and the board floats up.
I know it is not the same as a mono boat with a board, but thought. I could throw it out anyhow. I like my board.....

[Sailndive345]

Originally Posted by fcallard

My Clearwater 35 has a weighted swing keel (~3000#) which completely retracts from 5'11" draft to 1'10" draft. It is hauled via a winch-assisted block and tackle arrangement, but is lowered by gravity--like letting out a genoa. I asked the builder what would keep the keel from "falling up" in a capsize. His reply was that you ought to retract the keel in conditions that could cause the boat to turn turtle.

His logic? The keel could "trip" the boat coming down a wave, so you'd best retract it in these conditions. He asked, " Did you ever see a log capsize?"

The Clearwater 35 has about 5000# of lead ballast split about 50/50 between the very slack bilge and the leading edge of an elliptical keel, so that the boat is still well ballasted even when the keel is fully retracted. A conventional centerboard boat would have similar ballast considerations, but the Clearwater 35 differs in that there is no vestigal keel (like the Southerlys)and presents a smooth whaleback figure underwater when the keel is completely retracted.

So, it may make sense to retract a keel/centerboard when in conditions conducive to a capsize and thereby reduce the "tripping" moment. Food for thought!

Please excuse my ignorance - I am not very familiar with centerboard/swingkeel arrangements... I was trying to visualize what you described and thought of the conditions that would likely roll you; imagine they would feature very steep seas and heavy winds - and, I imagine you'd be running... If you retract your centerboard, don't you lose a lot of your tracking ability? It seems you'd be more susceptible to broaching?

Majority of my sailing has been with fixed fin keel type vessels - Is your boat equipped with a long keel+centerboard perhaps? I did understand the ballast part - what I am wondering is the kinetics.

Hope you/we never have to find out in real life!

Sailndive

[James S]

Originally Posted by Sailndive345

Please excuse my ignorance - I am not very familiar with centerboard/swingkeel arrangements... I was trying to visualize what you described and thought of the conditions that would likely roll you; imagine they would feature very steep seas and heavy winds - and, I imagine you'd be running... If you retract your centerboard, don't you lose a lot of your tracking ability? It seems you'd be more susceptible to broaching?

Majority of my sailing has been with fixed fin keel type vessels - Is your boat equipped with a long keel+centerboard perhaps? I did understand the ballast part - what I am wondering is the kinetics.

Hope you/we never have to find out in real life!

Sailndive

I was wondering the same thing....seems like in those conditions I'd definitly be looking for something to drop down.
It may be true that you don’t see any logs pitch poling...but what about rolling!

[Sharkman]

Hi

It may seem odd (it did to me at first), but putting the plate down when going downwind is the last thing you do with these "true" centreboarders. you sail them like a dinghy - as the wind comes aft you start to lift the plate and by the time you're broad reaching it's fully up in the hull. There is no external keel.

They are stable and not at all rolly downwind, and with the reduced wetted area, pretty quick - it's their best point of sailing. And if the boat tries to broach, there is no lateral surface to "trip over'. It's a different way of thinking, but it's worth bearing in mind just how many of these boats there are out there being sailed in exactly this manner, and it works just fine.

[Stillraining]

Mine not totally being a 100% centerboard...I can understand both sides of the argument of the broach concern ..I will still have tracking ability but it also makes perfict sence to me to get that tracking ability up as high as possibal..so you dont stumbel as readely compared to having it down if a broach does occour...I go from 4.5' up to 10.5' feet down.

[Sailndive345]

It sounds almost like the behavior of a powerboat(?) You 'slide' over the wave when turned sideways...?

[Sharkman]

Originally Posted by Sailndive345

It sounds almost like the behavior of a powerboat(?) You 'slide' over the wave when turned sideways...?

I don't know much about powerboats, but perhaps like a multihull with the board(s) up might be fair. With the plate up the boat should slide away rather than 'trip' over the plate if it's down in the event of a broach or being struck by a wave. We've never come close to losing control going down waves, although we haven't faced really extreme conditions (so far), but the boat has tracked well in all conditions downwind.

Talking to other owners the general consensus is that these boats handle as well as, or better than comparable deep keeled boats downwind. So far I'd tend to agree, and it's certainly far less work at the wheel than our old boat (7ft draft fin keel).