Foam Floatation...Is it needed?

[Steve K]

I make no recommendations on this issue, but here is my experience.

My 26 X had a 26 gallon water bladder under the V berth. Some of the foam was still in there too. The foam, sort of, held the bladder in place. I never noticed it sloshing around.
The boat sailed noticeable better with the water bladder full. I didn't notice any handling issues, when powering at full speed when the bladder was full and ballast was empty. I lost a touch of top speed, likely just due to the 230 or so pounds of extra weight.
The 26X, particularly the early ones (mine was a 1997) were pretty heavy in the rear, because the ballast tank went all the way to the transom. Later Xs tanks stopped short of the transom and there was a tunnel from the tank to the ballast valve. So adding weight up front, by water tanks and moving batteries forward seemed to help sailing performance, at least in the very early Xs. It helped get some of that big square transom out of the water and reduce some of the turbulence.

On to the D boat.........
This is really not a good comparison where sailing performance goes, compared to the power sailors,(the D is a rocket by comparison ) but I did want to mention that my D boat has a 20 gallon, round, fresh water tank, also under the V-berth. This extra forward weight seems to help the boat punch through waves without losing as much speed and doesn't seem to otherwise have any negative effect on the boat's performance. When this tank is partially full, it doesn't seem to have any effect on stability either...... even though I know the water in it must be sloshing around in this round, unbaffled tank.

I never stripped either of my Macs of all their foam floatation, but I have removed some at times to fit other things. I figure even with no floatation these boats would be closer to neutrally buoyant than boats that have #500 iron swing keels, like my Catalina 22 did. Who knows..... best to keep the PDFs handy in any case.

Someone told me that all those guys standing on the pictured, swamped boat in the add photo were about 5'3" and about 130lbs. soaking wet. Don't know if it's true, but it was a credible source.

I also can tell you that the less overall weight you have in any of these boats, the faster they are. However, I prefer to have mine stocked with plenty of beer, steaks and fresh water. And heck, just my toolbox/spare parts box must weigh 60lbs or so. and three batteries are way better than two

Best Breezes,
Steve K.

[JoeG]

Kadet,
When I purchased Nice Aft in 2004, I ordered it with a lot of options to be installed by the dealer. One of those was a thirty gallon (113 Liters) water bladder with an electric pump. Otho installed it in the very same area you are inquiring about. It has been there all of this time.

I also had Otho install the 30 gallon bladder. He stuffed the foam into the screwed down starboard hatch under the v-berth. I wanted to use that space so I re-stuffed the foam under the head.
I haven't noticed much difference in the sailing performance with the bladder empty, partial or filled. However, when the tank is filled it makes retrieving onto the trailer a bit more difficult. I installed the "roller mod" towards the front of the trailer to make it easier.

[Ixneigh]

I've added foam to my boat, and will continue to do so wherever I can.
Lol Otho wonder if he's a tattoo dealer now?
Ix

[Boblee]

The is normally bow low when ballast is in and ours is bow high when out even with the two 50l water tanks under the vee berth full it is still slightly high.
The aluminium tank divided in two that I made to fit in the forward space that was all foam, can become itself full flotation by closing the valves when empty but all the foam was reused elsewhere and some premixed cans poured in.
I would imagine filling the two forward tanks is balanced by filling the plastimo 150l bladder (holds 100l) under the aft berth but with it full and the front ones empty she certainly sat higher last trip due to not taking half the spares and tools for long remote trips most of which is packed under the two vee berth covers.
Whether the foam will ever be needed or not doesn't worry me but still have more in the boat now than when new, there are plenty of places to stow it leaving plenty of room for us travelling over 3 months a year, we have never exhausted space for packing tools, spares, food etc and you wouldn't believe what I carry.
We always empty the bow tanks first and then work on the aft bladder which I just found a leak in.

[Wayne nicol]

that trim is a good thing, i think Boblee. as i have had the boat described to me, is that the fore half is sail boat and the rear half is power boat, and when one sails( tank full) the boat is on its forefoot and behaves somewhat as a sailboat, and with the tank empty- in planing hull mode it behaves like a power boat, difference being, if you were powereing with tank full, then i geuss it would behave like a displacement power hull.
so i think always trying to keep these trim parameters in mind,while modding - could only help the boat. seems like your boat is as so!!

[Boblee]

When we were blowing out the cobwebs after 800k's of plodding at 2000 rpm (80 hr's?) the bow tanks were empty and the rear bladder almost so and still had the freezer midships but the bow was sitting way high, at 5000 rpm (WOT) the boat got to 25 kph (15.53 mph towing our aluminium dinghy (200kg loaded?) which was pointing to the stars and I thought that was pretty reasonable considering the weight on board and not quiet reaching plane.
In sail mode with ballast in and mast etc it would get way less as the nose would be harder to lift?

[Wayne nicol]

sorry bob, when i said tank i meant ballast tank- i wasnt very clear

[Boblee]

sorry bob, when i said tank i meant ballast tank- i wasnt very clear

Sorry bloke my bad.

[nedmiller]

I put a tank for water under the forward berth and removed foam to make room for it. The water tank sits low and I don't believe that it decreases the stability of the boat, and may, in fact, have increase it. I put an amount of foam that was substantially greater than the amount of foam that I removed into a plastic storage container and placed it in the rear of berth near the stern of the boat. That area way in the back was just wasted space for us. It might as well provide a space for floatations. The 60 hp 4 stroke Mercury Bigfoot on the Stern accounts for a large portion of the additional weight in the Mac. The bow, by contrast, has been very little additional weight and there is still a lot of flotation.

[Chinook]

Just noticed this thread. In response to the original inquiry, I did just as described in the original post. I pulled out enough foam blocks to accommodate a triangular plastimo water bladder. I was able to stuff all the removed foam chunks into various voids. The stuff really fits rather loosely as originally installed, and it wasn't too hard to fit the removed pieces back in, here and there. And considering the extra foam insulation I've installed around our electric frig, I'm not really concerned about the buoyancy of the boat, if it should ever fully swamp. Regarding the extra weight forward, I consider it a benefit for our X, since we tend to be heavy in the stern, with gear stowed in the kingberth, and kicker motor hanging off the stern mount. In the case of an M, the trim issues might be different. Two things about the forward plastimo tank: there isn't much drop for the water as it drains into our system. Sometimes, when I open the isolation valve to access the tank's supply, I have to push down on the bladder to get it started. Also, I believe the tank is rated at 31 or so gallons. With it fit into the vee berth space I really don't have enough room to fully fill it, without pushing up on the access hatch cover. I figure with my setup it probably only holds around 20 gallons.

[mastreb]

So I've very nearly sunk a boat with a thru-hull petcock installed by the previous owner that was kicked open by a passenger accidentally. The boat was a fin keel with a 6000# lead ballast, and it filled the cabin to 4' depth in about five minutes, which is how long it took to find the petcock and figure out (by listening underwater) what position was "off". And then we nearly hit a quay wall we'd drifted to within 5' of while we were dealing with the sinking emergency.

What I can say about the ultralight displacement and foam is that it will with certainty slow down the rate at which your boat sinks, which will give you more time to figure out what the hull is going on (since it's generally a mystery). I don't put a lot of stock in it keeping the boat from sinking once loaded to typical capacity. That said, the majority of it is up high, around the anchor locker, the mast step/daggerboard, the gunnels and the transom. So it's going to sink to the deck before the floatation really takes effect irrespective of load.

Most importantly, carry a bucket of this stuff: http://www.jamestowndistributors.com/us ... ?pid=63791

It solves about 80% of the "what the hull do I do about this?" problems you'll have on a boat.

[kurz]

what about using "waterproof" foam?
You could replace seat cushions with this safety foam and we could increase uplift force.
I guess the original foam froma the cusions is not whaterproof made!?

[mastreb]

what about using "waterproof" foam?
You could replace seat cushions with this safety foam and we could increase uplift force.
I guess the original foam froma the cusions is not whaterproof made!?

It's an interesting idea: I presume you're talking about a closed-cell foam that the cockpit seats would be covered with to perhaps a 1" depth, that adheres to the gelcoat? Or how would they be attached?

Something like "SeaDek" would probably work well presuming the density is lower than water, and with that stuff you could cover your seats, sole, and decks to provide additional floatation.

[Russ]

So I've very nearly sunk a boat with a thru-hull petcock installed by the previous owner that was kicked open by a passenger accidentally. The boat was a fin keel with a 6000# lead ballast, and it filled the cabin to 4' depth in about five minutes, which is how long it took to find the petcock and figure out (by listening underwater) what position was "off". And then we nearly hit a quay wall we'd drifted to within 5' of while we were dealing with the sinking emergency.

What I can say about the ultralight displacement and foam is that it will with certainty slow down the rate at which your boat sinks, which will give you more time to figure out what the hull is going on (since it's generally a mystery). I don't put a lot of stock in it keeping the boat from sinking once loaded to typical capacity. That said, the majority of it is up high, around the anchor locker, the mast step/daggerboard, the gunnels and the transom. So it's going to sink to the deck before the flotation really takes effect irrespective of load.

First of all, having a petcock in a place where it can be kicked is dangerous. Second, most of our Macs don't have any petcocks in the first place.
Third, as you mentioned, most of the Mac flotation is high and won't kick in until the boat is sunk to the gunwales.
Given all those factors, I'm not banking much on the unsinkable aspects of the Mac or its flotation.

[innervations]

Probably not very captain worthy but I am not going down with the ship

If my is sinking me and everyone aboard will be in the tender with EPIRB, handheld VHF and the emergency abandon ship bag.

Even totally filled with water I doubt my boat would sink completely because while loaded with Waeco fridge, water bladder, outboard, and 2 batteries I don't believe the volume and density of this stuff is sufficient to overcome the buoyancy of the boat. I have removed only minimal amount of foam from space above mirror. Granted is will likely be submerged to the cabin top but my plan is to tether the tender to the boat to keep the two together with my rigging knife handy in case the does sink.