Stove Top Heater

 Every fall someone re-posts the idea of heating the cabin with a flower pot on the stove. I was smart enough to test this at home, where the pot shattered, throwing hot bits around the kitchen. It is an unsafe idea that might wok sort of and might get you burned or your boat damaged. Just no.

 As long as the link stays live, here is the article I wrote for Good Old Boat about an improved stove top heater. This was written about 5 years ago, and I would not change a thing. It works. Stove Top Cabin Heater

 

The concept was simplicity itself:

• We already have an engineered heat source with fuel supply, regulation, and a safe base.
• The Dickenson Cozy Cabin Heater was/is nothing more than a burner, heat transfer space, and a properly sized flue.
• A stainless stew pot serves for the heat transfer space, though perhaps not quite on the stoves highest setting.
  
• A 1-inch flue is a good match for a typical burner, though perhaps not on the highest setting. 
• All of the exhaust will go up the flue. If the flue is the correct length, it will be no more than 100C where it penetrates the deck. No problem. Test and insulate as needed. The highest setting might allow some exhaust to go under the pot and out into the cabin. You can feel this with your fingers near the edge. Adjust.
  
• You can still cook, though more slowly, on the top of the inverted pot. The aluminum skirt conserves heat, for the pot, helps heat the room (more surface) and keeps the cooking pot safe. 
• A very low fan (I use one made to run off the USB port of a PC) helps distribute the heat. it will cook my F-24 in 20 minutes after which I turn it down. This is at about 35-40F.
  

I would turn it off before leaving or sleeping. But if the cabin furniture is warm, the cabin will stay warm for a while. Getting the furniture warm is important.

• The interior volume is about 300 ft^3, or about twenty pounds of air. The cabin furnishings weigh several hundred pounds. It is the furnishings that absorb the heat and keep the cabin warm. Kind of obvious, even though common sense tells us that the air is what we must heat.
   

Deck Level Wind Indicators

 Eagles have landed on my boat and eaten three Windexes. They play with them, like a cat.For now, I'm done giving them toys.

 

 

 

So I've started testing deck-level flies. I've been using pulpit flies for years on all of my boats (beach cat, Stiletto, PDQ, and F-24) and like them. The location has to be careful chosen and I used something different on each boat.

Now I'm looking at shroud ribbons and flies. I didn't like them on other boats, but they seem to suit my F-24. 

 

 

Two DIY versions, top, then Nautos and Davis Wind-Tel.

In fact, I'm liking all of them at first blush. I imagine I will stay with the one that holds-up best.

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The top DIY is on with Velcro. It does not spin, so it can wrap, but it always unwinds when the wind drops in a jibe. The second uses a DIY polyethylene spool (10 minute lathe project for the pair) for easier rotation, making it slightly more sensitive than the Nautos ribbon, but maybe not enough to matter. 

 

The Davis Wind-Tel ($65 per pair) is out of production, but there is lots of old stock around.  The Nautos Tell Tails are cheap ($10 for two sets) and though potentially fragile, work pretty darn well. Being able to spin vs. tied on really does help.

 

Any ideas? I'll test anything.

On the concequences of being "Protected"

From the King and I, the "It is a Puzzelment" monolog:

 

Shall I join with other nations in alliance?
If allies are weak, am I not best alone?
If allies are strong with power to protect me
Might they not protect me out of all I own?

 

You don't get protected without losing freedom as part of the deal. This is the same with individual freedom. Historically, it just doesn't work that way. Freedom is better. We can protect ourselves, as a group.

 

The Goofy X-Spread Rig on The F-24 MKI

10-26-2024, rev. 11-6-2024

The failure of an F-24 mast at the lower diamond wire junction this week (not my boat) started me thinking about the odd rig on this boat. It was not used on any other F-boat, and in fact, no other boat that I can find. Supposedly Gino Morreli designed the rig, but he's a smart guy and he never used this design on any other boat. I'm think it's far more likely this was a John Walton (son of Walmart founder Sam Walton) design choice, one of many that Ian did not approve of. Oops.

 

 The failure point was just above the lower (forward) diamond wires. Note also that it was sideways (as typical), not in the direction of the forward wires, suggesting to me that they are not helpful.

Mono-hulls are typically rigged with spreaders and shrouds anchored to the deck. This provides side support with no added compression load. The proportional stretch of the uppers and lowers insures that the mast remains accurately in column, even as it is slightly deflected to the side under wind loads. Masts, when they buckle are failing in compression. Occasionally a jumper diamond is provided on the front to control the bend of a very slender mast, though larger mast sections and those stabilized with pre-bend typically do not require this extra support.

 

One the left (F-24) rig there are two sets of diamond wires on each side. The drawing omits the outer set on the left and the inner set on the right for clarity. Those are not loaded when the mast is pressed to the side and forward reaching.

 

The weird F-24 X-spreaders. The forward spreaders hold the shorter wires. The aft spreaders are about the typical rake angle and provide the pre-bend. 

 F-24 manual image.

 

Multihull masts are often rigged with big rotating masts for several reasons. A big main is advantageous, as it provides accurate heel control through twist and easing the mainsheet. They can tolerate a heavier mast (rotating masts must be heavier because the staying is less efficient) because they heel less and as a result, the mast is not outboard, contributing to heel. They have a wide shroud base, reducing the need for spreaders to create angle. Often multihulls cannot sustain high mast base compression loads because there either is no center hull, or in the case of trimarans, because it is lightly built, without the need for structure to support a keel.  For the same reasons, rotating masts are nearly non-existent on monohulls. Because there can be no fixed spreaders to carry side loads, rotating masts use diamond wires, and it works out well that they rotate with the mast, supporting the weak side of a thin, aerodynamic wind section. Forward support isn't needed, because the mast is wide in that direction. The diamond spreaders are angles aft to help create some pre-bend, which helps with mast stability (resists inversion and pumping) and with draft control (you can de-power by de-rotating the mast which pulls cloth out of the sail, reducing draft).

 The combination of diamond wires, aft-swept spreaders, and aft-angled cap shrouds also helps eliminate the need for a fixed backstay, something that is problematic with a high roach mainsail, the other half of the quick-heel-control formula. It's hard to maintain enough forestay tension without a backstay, and savy multihull sailors quickly learn to compensate with a tight mainsheet.

But the F-24 MKI mast does not rotate, so why the diamond wires, instead of fixed shrouds? It's easier to step the mast when trailering, since no tensioning is required. The center hull is relatively narrow and very light, with no good place to anchor the shrouds. There is also the need for aft-raked cap shrouds to replace the backstay. Of course, many cruising cats have either conventional shrouds or diamond wire stays with aft raked cap shrouds and no second set of diamonds.

There are several problems with the willy-nilly addition of stays without working through the design. When a mast fails, it fails in compression. Like buckling a drinking straw, the tensioned side does not tear, it is always the compressed inner side that buckles inwards. Every additional wire and its associated pretension adds compression, so unless it provides needed support, it actually weakens the mast. The more wires, the more compression. Calculations of buckling strength for this mast sections give a compression working load of 6,500 pounds. Rough calculations based on wind pressure and heeling force (the boat was reefed and very close reaching) and bending moment at the failure point  show that the mast failed under a compression load of about 12,000 pounds (if distributed--this reflects the probable stress on the side that failed). This is well over the safe working load of the section, but less than the expected failure strength.

If we total up the compression loads from the shrouds, diamond wires and other rigging ...

• Forestay. 2200 pounds
• Shrouds (only one is under much tension sailing under full load). 1200 pounds
  
• Mainsheet. 300 pounds
  
• Halyard, jib. 300 pounds. Note, jib halyard tension does not change forestay tension + halyard tensions at the mast, only between the mast and the anchor point at the furler. The total is fixed by shroud and mainsheet tension contributions.
  
• Halyard, main. 500 pounds
• Cunningham. Does not count, since it just offsets friction in the mast groove, from head to foot.
  
• Forward diamonds. 1000 pounds total (but not included at failure point)
  
• Aft diamonds. 2400 pounds total

... and adjusting for angles (only part of the tension is directed in-column) we get about 6,500 pounds total. That does not allow a lot for bending moment. Curiously, 36% of this is from the diamond wires and 10% from the forward diamonds, which we don't need; there is very little forward load on the mast, and the center of the force is near the head of the sail (forces perpendicular to the luff tape are very low, except near the head and tack--not the wrinkles, the luffing when backwinded, and the lack of significant reinforcement on the slug grommets).

The rigging guide gives 500 pounds max for the forward diamonds and 1000 pounds max for the aft diamonds. But what if they really don't need pretension for stretch, since the mast is not bending? Then the pretension for the aft shrouds needs to be just enough to establish the prebend (0.8% of length), and forward diamonds just enough to keep them from going slack, since we probably do not need them at all. But I'm disinclined to remove them entirely, and going slack might allow them to jump out of their fittings. 

10-29-2024. I checked the tensions on my F-24 MKI.

Wire                  Observed (pounds)              Maxium Spec (pounds)            Re-set to (pounds)

Shrouds             800                                      1500                                           (adjusted each sail)

Forestay            (same as shrouds by geometry, except as increased by mainsheet tension)

Aft Diamond     1400                                    1000                                           800

Fore Diamond    800                                      500                                             350  (below failure)

Total Diamonds  4400                                    3000                                           2300

 This represents a (4400-2300)/6500=32% reduction in mast compression, which translates dirrectly into a 32% increase in strength. 

 Worse, exactly where the reefed main applies it's greatest force, just above the forward diamond wire anchors, the lee diamond wire is pulling down and to leeward. And that is where the mast buckled to leeward with a reefed main. The smoking gun. Removing or slacking the forward diamonds also reduces this stress. 

What if the mast raising stays were snugged and perhaps reinforced in the deck (Lower shroud)? This is a conventional rigging solutions? This stabilizes the lower mast with less compression in the critical area. It would also help to move the anchor point slightly aft and outboard, while staying inside the jib track.

Takeaways? The forward diamond wires increase compression and pull in the wrong direction without providing any useful improvement in mast stability. Best would be a re-designed mast with only one set of aft-swept spreaders. The less drastic solution is to reduce the tension on the forward diamonds; I judged 300 pounds to be sufficient preload and sailing observations confirmed they do not go fully slack.The aft diamond wires should be just tight enough to create 2.5 inches of pre-bend (as specified by Ian Farier)  and no more. These serve a purpose, but extra tension does not help. 800 pounds appears to be sufficient, and I may reduce this, based on further sailing observations in strong conditions. 

Will I reinforce the deck and improve the lower shroud? Undecided.

Time will tell, but I'm comfortable with my calculations. The mast should now be 30-35% stronger, no small improvement.

3D Genoa Leads

 I've written about this for Good Old Boat and Practical Sailor, but I still get a lot of questions.

My F-24 came with pin-slide cars and an out-hauler. As long as the sail was fully deployed, this worked adequately, though occasionally a little more leach tension was desirable. When the jib was roller reefed, however, the car needed to be run all the way forward, which wasn't a lot of fun when the conditions were rough enough to require it. Lots of spray and flogging. 

Converting to 3D leads was simple.

• The car is set most of the way back, to the full sail, windward sailing setting.
• A bulls eye bushing was fitted to an odd car I found in the free cycle bin. It was originally used to mount a ladder on the rail, but by cutting away the end and fitting a bushing, it became a low profile block. However, any car that you can attach a pulley or low friction ring to would work. The forward track hold down bolt could be replaced with an eye bolt. Many possibilities.  The main thing is to have at least 2:1 purchase so that it can be adjusted under some load, though not necessarily full load.
• A climbing rap ring is used as a sheet guide. They are nice because there is plenty of room inside for all the lines. But a low friction ring or sailing ring could work.
• Cam cleats for both tails.
• I spliced the tails into a continuous line. This reduces tangles and makes it easy to sort out. When one is in the other is out, so it reduces the tail clutter in the cockpit. But they could be separate.
• The line is bare Dyneema single braid for low friction. The tails are covered with polyester to make them large enough to handle and so they will hold well in cam cleats. I used Samson XLS and disposed of the core, after using it to pull the Dyneema through.

The new system allows lead adjustments in just a few seconds to any position. Small wonder all of the sport boats do it this way now, right on up to about 50 feet.

Jib hauled out when reaching deep

 

 

Normal windward setting.

 

 

Hauled forward for a reefed jib.

 

 Hauled out just a tick for very close reaching

 

 

Close-up of bullseye fairlead.

 

 

Not a great picture, but you can see the two cam cleats and the red/white line/loop that controls forward and outhauling

 

 

 

This is a Non-political Blog ...

 ... But it is also my blog.

I started as a Republican. I voted for 

• Gerald Ford. A good moderate guy with a terrible set of cards.
• Ronald Reagan. He had some tough times near the end.
• George Bush Sr.
  
• Bob Dole. I wasn't impressed, but I was less impressed with Bill.
• George Bush Jr.once. He turned out to be too full of himself and not entirely honest.
  

 And that was the last time I voted Republican.

• Barack Obama. I really wanted to vote for John McCain. I believe he is a very good man and would have been good for the country. But I also though Obama could set a valuable precedent. I remember, on election night, feeling that I would be happy with either.  They were both presidential. Mitt Romney would have been OK too.
  

And then we made a turn.

• Hillary Clinton. She could be irritating, but Trump made his money stealing from people in the casino business. I was brought up to believe gambling was a sin, and that casino owners were in the same catagory as pimps. I still feel that way. A moral person just can't enjoy stealing from people. And why was anyone surprised that he turned out to be a narcissist showman a pathological liar? It was ... obvious. Why were we surprised that the world did not respect him?
  

And now it has escalated miles past the point of ridiculous and scary. It seems there is no action or statement or threat that shocks. There is no red line, not in law, not respect for the process or even Constitution. January 6th he proved that he was a dangerous megalomaniac. 

But more damning for the Republican party is that the only thing they can do is circle the wagons and double down on ... a mistake. They have lost the ability to lead or frankly, to think for themselves. They can only rush to see who can spout the most bile. There are better Republicans. Are they hiding? I believe, hopefully, that many are mortified with the state of affairs, mortified that Trump can be presented as the best statesman they have to offer, but at the same time certain that if they put one toe out of line they will be dissected. As a former loyal Republican, I feel sorry for those that have been attacked and marginalized. There are good people in there. But they seem to be fading.

I would have voted for Nixon. He did a lot of good things. He also did one bad thing and, his own party had the character to confront him with it. He had the character and honor to resign. He appointed a good moderate man to succeed him. I respected that. I thought it would be good for that party in the long run. I think it was.

 Now, the Republican party, the party I supported for decades, has lost it's compass and its sole. I don't think they have any idea where they are heading. They seem to have lost track of right and wrong and even the rule of law. I really hope they can start over. I fear they cannot.

I hope Kamala, should she win, will aim for the center. Not too progressive. It might help the Republican party move to the center as well. As I see it, views change slowly, and the US has moved to the left faster than people can adjust. We've made a large group  uncomfortable. Again, I'm not saying whether that is right or wrong, only that it is true. I'm saying a people just can't change that fast. Real change takes generations, and slow but steady is probably better than two steps forward, then three steps back. The result has been an obscene and sometimes violent overreaction back to conservative values, which too often manifest as mean values. Fear plays a big part, and power-hungry people have always known that feeding fear is a cheap short cut to power. We need to be brave about change.

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America is great, and becoming greater all the time. I've lived here a good while, and you can't convince me it was better 20, 40, or 60 years ago. It wasn't. Isolationism and protectionism have always lead to inflation and slowed economic growth. Engaugment and competition lead to growth and greatness. 

The world is different and at the same time better, but not all people can acclimate to change. We probably do need to slow the rate of change, not because it is right or wrong, but because it is necessary to allow people time to catch up. 

I could, of course, be wrong about everything. Opinions are like that.

 Next up, testing fenders ... but not like this.

 

Maybe more like this. I'm thinking about low freeboard and flat fenders, since they are more applicable to my F-24.

Wrinkles

 I've sailed with polyester sails lots and understand adjustment by stretching. I understand rotating masts and bendy masts and how they affect shape. If you ease off the main halyard in light air, for example, the sail becomes for full and powerful. There are some wrinkles across the bottom, but they do little harm and the sail is faster than if you stretched it tight.

But this is less applicable  to laminate sails. They stretch, but far less, and most of the shape is baked in when they are made. For example, if I really yank on the downhaul to eliminate these wrinkles (basically balancing the mainsheet and outhaul tension) I don't expect to see much change in draft or draft position. Thus, I assume the goal is normally to reduce wrinkles, since they are not the result of any beneficial shape manipulation by stretching (or not stretching) and they will disrupt air flow. In fact, eliminating wrinkles probably takes you closer to the original design shape. Smooth seems fast.

With and without Cunningham tension. A slight difference in camera angle. but if you lay a straight edge on the battens, they are the same. Without a trial horse sailing next to me, I can't honestly, accurately say which is faster because of wind and wave variations.

 

If I measure the draft and position of draft with a ruler I see no change. It seems like sheet metal. It will wrinkle if the fit is poor or if we ask it to make a compound curve.

• Jib. When the sail is first hoisted the luff was straight. When the wind comes up the luff is curves (sags), reducing the straight line distance between between the head and tack. If we don't pretension the sail it will bunch up on the forestay. These wrinkles are primarily horizontal and don't hurt much. We need to be cautious of over tensioning the sail if there is a furler; they don't like rolling under high load.

• Main, square top. The leach is falling away, requiring the top of the sail to take a potato chip shape if there is any design fullness (broadseam). Unless the sailmakers cuts this area very flat, the molded-in compound curve is violated. 

• Mainsail, tack and sliders. Often wrinkle radiate from these (polyester too), and the cause is often that the tack or reef grommet is not tight forward, but has been pulled aft by the outhaul. Even sheetmetal would wrinkle, because you have pulled it out of square. The tack and Cunningham tackles need to pull forwards as well as down. Reef tackles too. A very common shortcoming.

While I'm sure there is some bias stretch, these specific wrinkles can exist without stretch.

The question is whether stretching a laminate sail to remove wrinkles has any material effect on shape, or whether the wrinkles are generally the result of either poor fit or incorrect installation/rigging.

(I've intentionally skipped a lot of factors for brevity. It's just a forum tickler. Mast bend. Rotation. Headboard misalignment. Forgive me.)

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I'm ordering a new laminate main, not because I don't like my current one, but because it is showing signs of delamination. It's old but still has a nice shape. Until it blows ....

Fender Washers--Basically Worthless II

12-10-2024, Rev. 8-17-2024

This spring I spent several weeks replacing a bunch of rotted deck caused by the use of flimsy fender washers.  That encouraged me to dredge up this old post. There are longer versions, with more data, in Practical Sailor and Good Old Boat.

As ramp-up for some Practical Sailor testing, I thought I would share a preview.

First, unable to secure scraps of deck material for which I could be sure of the pedigree, I laid up some of my own. The testing will based upon 1/2-inch balsa core with (1) 6-ounce cloth and (1) 17-ounce biaxial layers on the deck side and (1) 17-ounce biaxial layers on the under side.

I drill a 1/4-inch hole (no epoxy plug, block of wood on the back side) and tightened down a fender washer against it. At 10 in-pounds (about 675# load) the washer had distorted and the laminate was failing. for comparison, the bolt working load of a Lewmar 40 winch (1/4-inch bolts) with a strong grinder is about 500 pounds each. In other words, without an epoxy plug the bolt will fail under working load and standard ASME bolting load, with no safety factor for aging and fatigue. It is about 5x weaker than good design suggests. It also explains why I had a PO installed winch rip out.

By 18-in-pounds the fender washer was buckled and the nut was well into the core. For comparison, this is about 50% better than a plain pine board in each case.

I repeated the test with only lock washer. The same result! The fender washer resulted in no increase in strength. The point being, that the bolting washer provided better support in close, the end result being the same.

Testing for the actual project will involve proper epoxy plugs. However, since under the load the bolt will NOT be supported on the other side (the winch or cleat will be lifting) in the real world, the top side support will be supplied by a 4-inch diameter ring spacer, allowing the washer to pull through, if that is what it wants to do. I've tested this without the epoxy plug; not surprisingly, it lowers the failure load and creates top side damage much like I saw on my failed winches.

We'll see. But for now, the moral of the story is that fender washers are basically useless; they fail as soon as they are actually needed.

 You can buy extra thick fender washers that are double the thickness, 4 times the strength, and 8 times the stiffness (that's the way increased thickness works). Bolt Depot has , them, as well as many others. This is what the chandleries, including West Marine and Defender should carry. But they would be higher in price and we would buy the cheap ones. Which is why chandleries don't sell crappy rope. They shouldn't sell crappy washers.

[From Bolt Depot. Buy the extra thick ones.]

 

 

How to Pronounce Kamala

At my last job too many employees made a joke out of mispronouncing a Greek employee's name. It was insulting and said much about those employees.

It's really very easy. 

Comma-La

How to pronounce Kamala

Getting it wrong is embarrassing and disrespectful. It's not "former president Tramp." I guess it could be ... but that would be an adjective related to documented behaviors and I wouldn't capitalize it. Never mind, that's off the point. Donald Trump was elected President from 2017 to 2021, and I can respect that as the will of the people.