Volume of 26M Daggerboard

[Dirko]

Has anyone calculated the volume of the dagger board for the 26M?

I'm trying to figure out what my options are if I go ahead with dropping some lead in the bottom.

Cheers,
Craig

[Russ]

It's been done by others. The biggest problem is the dagger is thin and bulges when filled.
I believe some have used spent bullets from gun ranges.

[raycarlson]

No need to worry about volume, it could hold way more weight then you could lift with a 1:1 pulley. Only effective reason to add lead shot is to help board drop or extend downward fully in a shorter time or while moving forward at slower speeds as at 5mph stock board will not drop at all as friction binds it in place. Drill a one inch hole one foot above bottom edge, add 8-10 pounds lead shot #8 or #9, then pour in 1-2 cups of resin on top to seal it in place. Leave one inch fill hole open to act as drain/vent for raising and dropping.

[mastreb]

Most people who have added lead weight have reported insignificant improvements in pointing, tenderness, and performance, with the penalty of additional risk of accidental dropping and heavy lifting or pully requirements.

If you decide to do it, the best way to do it without bulging the board due to weight is to drill a small hole at the height you want to fill to, then add small amounts of shot and small amounts of resin in 1" or so "steps", allowing each step to cure before adding the next. This prevents the weight of the shot from causing the board to bulge as you fill it with shot.

Honestly you'll get better pointing and handling performance by adding an autopilot and using that to make course corrections than by making the daggerboard heavier. Routine use of the autopilot for all steering did more to "steady up" my boat than anything else. I only manually helm now when the sails are down and I'm pulling into a marina or in an tight-quarters emergency.

Tenderness you just get used to.

[raycarlson]

Agree on that for sure, only gain will be not waiting on dagger board to fill with water and slowly sink downward, no handling improvement whatsoever. One inch of lead shot is more than enough, one inch equals about 10 pounds, more than that it's getting to heavy to pull up with the factory system.

[Dirko]

Ok - time for me to come clean. This'll be a little contentious - there are lots of opinions on weighted dagger boards floating around.

I cracked my dagger board when I grounded it trying to outrun a storm. In spite of that incident the likelihood of grounding where I sail is slim to none if a person doesn't come into shore at a rate of knots. I learned my lesson from the last grounding.

Rather than just epoxying the board to fix it, I started thinking about a new board. It would be a nice improvement if I could make the boat lighter and less tender at the same time. Seems one of the shortfalls of water ballast is that the CG is relatively high, so you need more weight to balance the boat than if it were a traditional keel boat. I'm guessing the CG is just above the waterline. I'd need some help from Matt or others to let me know if I'm off-base, but I figure with a roughly 350 lb. dagger board, I can get the same righting lever that I currently get with the water ballast. If I built a stainless, lead-lined dagger board I'd end up with about 750 lb in the board and a 60% improvement in righting lever. I'd be able to sail without water ballast, be a little lighter, be much less tender even with some additional sail. (Need a new main - my genny is about 155% vs. the factory 140%) When the wind blows harder than 15-20 knots, I'd add the water ballast back in and be able to keep some sail up. I've had a good look at the winch I'd need to raise the board and the reinforcing I think I'd need around around the top of the deck.

All my sailing is on a lake. Rolling due to waves isn't a problem. Anyone who has broached out here, has just been stubborn and not reefed when the wind picked up.
Most of the time the wind is around 8-12 knots, however it's over 20 knots about 20% of the time - especially spring and fall. It would sure be nice to look over the stern at a few of the hard core racers around the lake.

So - anyone know the volume of a 26M dagger board?

Cheers,
Craig

[Be Free]

I suppose if you currently keep your boat on the lake year round and never drain the ballast you may get a slight performance boost by being able to carry more sail with less heeling. However, if you trailer it wouldn't you be carrying that 750lbs on your trailer instead of dumping the water back in the lake. On a factory trailer that could be a problem. Also, if you ever raised the board you would have moved your cg much higher in the boat than it is with the water ballast. It would similar to raising the entire ballast tank some distance above the cabin deck.

Raising the board is going to be interesting. The winch will certainly be needed but I doubt if the rest of the hardware for the stock daggerboard would be able to take the additional strain. Also, don't forget to factor in keeping the board up while under power. Even bouncing through a light chop with 750lbs hanging above a hole in the bottom of the boat is going to be a significant force to be reckoned with.

At first glance it looks like you may be trading a lot of problems under power for a minimal improvement under sail.

[Russ]

I suppose if you currently keep your boat on the lake year round and never drain the ballast you may get a slight performance boost by being able to carry more sail with less heeling. However, if you trailer it wouldn't you be carrying that 750lbs on your trailer instead of dumping the water back in the lake. On a factory trailer that could be a problem. Also, if you ever raised the board you would have moved your cg much higher in the boat than it is with the water ballast. It would similar to raising the entire ballast tank some distance above the cabin deck.

Raising the board is going to be interesting. The winch will certainly be needed but I doubt if the rest of the hardware for the stock daggerboard would be able to take the additional strain. Also, don't forget to factor in keeping the board up while under power. Even bouncing through a light chop with 750lbs hanging above a hole in the bottom of the boat is going to be a significant force to be reckoned with.

At first glance it looks like you may be trading a lot of problems under power for a minimal improvement under sail.

Well said.

Exactly what I was thinking. The boat could possibly be quite dangerous with no ballast and board up. 750 pounds that high is a lot. My son and I were on deck no ballast and the boat started to tip over. kind of freaked me out. This would be the same thing.

Powering would be quite dangerous without water ballast.

Forgiveness goes away. I think the dagger trunk is pretty solid, but what if the dagger were steel? Not so much.

The only way this makes sense is to keep most of the weight low on the dagger.

[RobertB]

Rather than just epoxying the board to fix it, I started thinking about a new board. It would be a nice improvement if I could make the boat lighter and less tender at the same time. Seems one of the shortfalls of water ballast is that the CG is relatively high, so you need more weight to balance the boat than if it were a traditional keel boat. I'm guessing the CG is just above the waterline. I'd need some help from Matt or others to let me know if I'm off-base, but I figure with a roughly 350 lb. dagger board, I can get the same righting lever that I currently get with the water ballast. If I built a stainless, lead-lined dagger board I'd end up with about 750 lb in the board and a 60% improvement in righting lever. I'd be able to sail without water ballast, be a little lighter, be much less tender even with some additional sail. (Need a new main - my genny is about 155% vs. the factory 140%) When the wind blows harder than 15-20 knots, I'd add the water ballast back in and be able to keep some sail up. I've had a good look at the winch I'd need to raise the board and the reinforcing I think I'd need around around the top of the deck.

All my sailing is on a lake. Rolling due to waves isn't a problem. Anyone who has broached out here, has just been stubborn and not reefed when the wind picked up.
Most of the time the wind is around 8-12 knots, however it's over 20 knots about 20% of the time - especially spring and fall. It would sure be nice to look over the stern at a few of the hard core racers around the lake.
Craig

Check out the Dudley Dix Didi 26. This uses a similar foil with I think a 900 lb lead bulb weight on the end. A very high performance 26 foot planing hull sailboat with a cabin.

[raycarlson]

The last thing I would worry about is reinforcing the upper deck. I would be much more concerned with 750 pounds flopping around side to side and back and forward with that 4 foot moment arm and only 12 inches in the thin walled dagger trunk. There is a little bit of raw poly resin mixed with sand poured around the hull-dagger trunk but not half enough to take 750 pounds of flopping steel daggerboard, the factory dagger board is very thin walled and designed to fracture and break apart upon contact with anything solid so as not to crack open your hull at the hull-dagger trunk joint. It's a Macgregor not a racer, I'd consider buying a little hobbie 16 for racing and leave the mac for relaxing.

[Chopper Pilot]

I have thought about many attachable units that can be lower into the water one by one and connected to the bottom of the dagger board. That way the are not always attached, hanging while trying to lower and raise the DB. Lower them one by one with one of the winches and bolt them in place. You still keep the fracture ability of the stock DB, with the pendulum weight of a keel. I thought about doing this by making my own using a long aluminum rod sandwiched between two boards of plywood covered in fiberglass. The end of the rod would have a flat aluminum plate with many mounting points for the weights, which would be numbered and shaped into a very hydro-dynamic shape.

[Dirko]

Also, don't forget to factor in keeping the board up while under power. Even bouncing through a light chop with 750lbs hanging above a hole in the bottom of the boat is going to be a significant force to be reckoned with.

Really good point. Might be why Pearl Noire opted for the bulb instead of weighting the whole dagger board.

I didn't see any comments from the people who weighted their boards on how it affected their motoring experience. Anyone hear any feedback?

I like the idea of a removable bulb, but thought it was just as likely that the extra drag would offset any gains, other than stiffening the boat in bigger winds.
Madd Mike added a 100 lb wing on a pivot to the bottom of the swing keel on his X. Another option to consider.