Sand Bags

[delevi]

Objective (may be obvious):
1. add stability
2. ballance the hull so the bow doesn't dip down when ballasted
3. reduce heal via 400 lbs additional ballast (removable)
4. emerse more of the aft section in the water to add stability when seas are on the beam or aft quarter

Some of you may have read my prior threads on issues with hull balance for heavy seas. This is a possible solution I'm considering.

Get 8 sacks and fill them with sand (50 lbs per sack.) Possibly mix the sand with some epoxy to give it form. Put the sacks under the aft berth bilge/storage compartment which is essentially useless for storage. This would add ballast where I believe the boat needs it (under the cockpit area) and perhaps achieve the objectives above. Nice thing is it can be removed when trailering to areas which don't have heavy winds and seas i.e. inland lakes. Wondering if this would completely destroy performance under power, however. Any thoughts?

Leon

[Chinook]

I have an X, not an M, and my problem has always been too much weight, not too little. The problem with trim on the X tends to be a light bow, just the opposite of what you have. I'm not so sure I'd want to be loading and unloading 400 lbs in the king berth area on a routine basis. Also, I'm wondering if it would create a center of gravity issue, being several inches above the bottom of the bilge. Have you considered ballasting with beer, instead of sand?

[delevi]

Sand is free But you might be on to someting. That space may not be entirely usesless afterall. Could store quite a bit of beer down there The bilge under the aft berth sits right over the ballast tank. The center bilge is separated from the side bilges. I plan to only use the middle portion to keep the weight where it should be. I don't plan on loading and unloading often. 90% of my sailing is in salt water when I'd use the extra ballast. I would only unload when trailering to another sailing destination. Otherwise, the boat will be in its slip with the sand ballast in place. Using 50 lb bags would make it manageable to load/unload.

[bscott]

Awhile back someone was debating the value of using 4" PVC pipes for extra balast, pumping water into them. Maybe you could insert some pipes between the balast tanks, pump water in/out? No hernias, no mess, no fuss.

Bob

[beene]

I still say water is the way to go. You can add and remove it underway. Use bags of sand, you are stuck with the weight, less speed when motoring, more fuel burn, less range from your tanks.

You just want more ballast.

Use water.

I suggest tanks or bags, placed under the forward starboard dinette seat, and the port bench seat for starters. If you do not like the ballance there, move them aft until you are happy. Use a water pump with hoses to add and remove the water at sea. Any size will do. Water adds a lot of weight for its volume. Won't take much before you have added hundreds of lbs to your ballast ratio. Not enough weight? Get some more tanks or more bags and try again. Whether you use the area beneath the aft berth or some place else, keep the weight low and you won't have a problem. Just keep in mind, the ability of the Mac to float with a whole in it will have gone by by.

I think you are on to something by adding more ballast.

Just remember, the hull design will always be your nemesis.

The amount of freeboard and lack of ballast to sail ratio is a problem.

Good luck with your trials Leon

G

[delevi]

Ok. Let's look at water.... I would like to keep it under that aft berth sooo... a few issues to tackle. Where can one get a heavy duty water bladder that is say 6 feet in length, 2-3 feet in width and 3-4 inches height? Might be tough. Water weighs 64 lbs per cubic foot compared to sand 90 lbs per cubic foot so let's say I go from 400 lbs ballast to about 275 lbs. I can live with that. Now how in the world do I fill and drain? I guess filling can be done with a hose at the dock.. can't see how to fill while at sea. A water pump, at least the type I installed for my galley takes a good 15 minutes of running non-stop to empty my 13 gallon fresh-water bladder. It would take an hour to drain a ballast bag I think. Ideally, to install a second ballast tank, independent of the primary one would be the way to go, though not very realistic, at least to one with my limited abilities. If anyone has ideas on this I'm all ears. Sand, on the other hand would be a good way to experiment. The only cost would be to buy some sand sacks and some twine. Then load up at the beach.

On edit: by adding 400 lbs of ballast and counting 150 lbs additional ballast I already have from the weighted keel, would bring the boats ballast/displacement ratio to a whopping 53% That's a remarkable ratio, though granted it isn't deep down under water. If it was, it would rival most keel boats.

Leon

[Boblee]

The 150 L Plastimo bladder gives you an actual storage of 100l under the rear bunk which would be approx 220lbs and if you were really keen you probably could find some smaller bladders to fill the smaller areas and they could be used elsewhere in the boat as well.
The good thing about water is that you can use it to drink but if you don't have a shortage perhaps just for day sailing etc and trying to find the best ballast placement sand would probably be easier.
In our case pumping water in or out of the boat is not a major problem and filling small water bladders would be easy even underway but really too much weight has been more of a problem rather than too little.
Maybe down the board could be helpful.

[Terry]

I already use extra water ballast! I keep my 50L square plastimo bag just aft of the companionway ladder and it is usually kept full until we go on extended trips in which case it gets depleted fast through the galley sink. In hindsight I wish I got the bigger 150L rectangular bag. (Maybe I should buy a second 50L bag) I also keep my extra house battery under the ladder. If I was really bent on extra weight I think I'd buy it in the form of a bigger engine. I also carry quite a bit of bottled water, gatorade and soft drinks which also adds weight, not to mention all the other stuff I pack around that adds to ballast. Maybe you should haul your boat and weight it on commercial scales to see what your current weight is, you might be surprised.

[delevi]

The thing with those plastimo bags is they take up a lot of volume. The depth of that center aft bilge is only 4 inches or so. The side bilges are even shorter, which I would stay away from. The compartment under the ladder houses two batteries on my boat. Port side bilge under the galley has a 13 gal plastimo bag to supply the galley w/ fresh water via electric pump. As I recall, I paid something like $85 for that bag. Getting several of them can be a costly proposition. How do you guys propose pumping water in & out? None of the other bilges are an optin for me since they provide storage which is already scarce.

Leon

[Moe]

The 150 L Plastimo bladder gives you an actual storage of 100l under the rear bunk...

According to your mod page it only gives you an actual storage of about 80 liters. Did you find a way to rearrange it to pick another 20 liters?

Also, it appears there is some length to spare with your 150 liter tank. Do you think the longer 200 liter tank would fit under the M's aft berth?

[ronacarme]

1. Wouldn't the added weight in the stern immerse more transom, thus increase turbulence in the water trying to leave the transom, thus add drag ,and thus reduce sailing speed?
2. Wouldn't the added weight immerse more hull surface, and thus add skin friction drag and weight of water displaced per mile, and thus slow sailing speed?
3. If the problem is that the boat wanders from side to side of the intended course while sailing broad reach, due to big waves hitting the transom and lifting the windward quarter of the boat, might not such wandering be reduced by reducing (not increasing) the immersed area of the transom?

As to 1and 3, Weston Farmer in his 1979 book "From My Old Boat Shop" at page 171 notes as to operation at "soft" (displacement ) speeds, most boats
"will run more cheaply if trimmed so that none of their length is submerged at the transom. In low-speed ranges, double-enders and fan-tail stern types move with the least power. Transom-sterned boats that have great areas of the transom under water, and cannot be made to plane, are energy hogs for fair.......at low speeds such boats....have a large burble following them, and are unmanageable as well as being large drinkers of great gobs of power...."
but if same can be trimmed so that only an inch or two of the stern is immersed....
"you will find greater relative economy in getting places"
and at page 174
"these craft are unsteerable when checked down in a following sea"

[delevi]

Ok. Is there a solution?

[beene]

I was thinking, if you were insisting in using the aft berth as your ballast location, how about a waterbed bladder.

They are tough. Should not ever leak.

As for water pump in and out, Alex showed me his setup, high volume submersible water pump with a hose. He just tossed it overboard, hit the switch, and the water was coming out of the hose as if hooked up to your house.

There has to be a pump of some kind that can do the same for getting the water back out of that bladder when you want to dump it.

G

[Oskar 26M]

It might have started with sand bags, but have been monitoring this thread with great interest:

"these craft are unsteerable when checked down in a following sea"

I feel like endorsing that comment after my first real experience in my 26M last weekend of wind and sea conditions that are fairly common during our summer sailing season.

Towards the end of a great spring day-trip out to a nearby island, I had a 6 nm run back to my boat harbour. We had dawdled a bit at the island and I had a boat-storage area close-off deadline to meet so I gave up the idea of sailing back.

I started in the lee of the island. Winds were 20-30 degrees to starboard of the stern. Available coastal monitoring records indicate wind speed was probably not dramatic, maybe 20-25 knots. Observations on board were consistent with the shore monitoring records, suggesting winds at Beaufort Scale 5-6 and Sea Disturbance Number between 4-5 but increasing. Seas were ameliorated in part by the island's protection, but were complicated by some residual cross swell finding its way around the island. The result was that on the course I wanted to maintain, once I left the lee of the island I had seas of fairly widely varying heights, hitting the transom of my at 20-30 degrees.

Initially, I decided to try a fins-up power run at around 12 knots. Bad Idea. Oskar rolled and slewed wildly whenever a large sea hit the stern and felt quite unstable. My novice, but very macho "crew", having enjoyed a fairly gentle bow-on breeze in the morning, suddenly decided that my earlier advice to wear PFD's, was not a bad idea. One good outcome from the trip!

I dropped some fins and slowed to 5-6kts. Oskar behaved much better, but it was still quite difficult to maintain the course I wanted.

At no time did I feel that the was in an unsafe state, but it was unpleasant. It was a also lot more work dealing with the following/quartering sea than had been my experience with my previous sail boat. That boat's design was closer to a double ender. However, because it had no transom, my previous boat's outboard was stuck through a wet well, and it was not uncommon for the prop to come out of the water during heavy following seas. That wasn't a significant problem on the in the conditions I described above.

No doubt my ability to deal with these conditions will improve as I gain more experience and confidence in the , but any advice from more experienced Mac sailors how to handle a quartering sea would be most welcome, as would any way to improve steering through better ballasting or trim.

[Boblee]

Will be interested to hear any solutions to what you experienced Oscar as I have copped it a few times myself, the last was up the Gulf this year on a 20km stretch between two islands but with a 5 knot tide running across and a 20-25 knot wind 20 deg astern with a very confused sea it made it really hard to read and hold course when hit.
While I felt the Mac hard to control like you I never felt threatened, I wish I could say the same for the wife.
I also tried the 12 knot caper but gave that up fairly quickly
When we arrived at our destination she said although she was terrified she felt I had handled the boat well which was a surprise considering the looks I was getting for the hour before.