Divemedic

No Longer Paying

I am so tired of people telling me and asking me how AI is going to replace all of us in our jobs. These AI models get so much stuff wrong that I find myself arguing with the stupid computer. Here is a great example:

I was researching water flows for the drains in my rear concrete deck. Grok insisted that this narrow channel of 2 inches deep by 1.5 inches wide can move 240 gallons per minute of rainwater. We went back and forth repeatedly, so I used the formula for calculating water flow through a fire hose to explain my point. Here was what it said:

Why the Formula Doesn’t Fit Your Deco Drain

  • Your drain operates under gravity/open channel flow, not high pressure.
  • The “pressure” (head) is extremely low — usually just 0.1 to 0.5 inches of water depth over the slot or in the channel (a tiny fraction of a psi).
  • Water enters gradually along the full 24 ft length, and the channel flows partially full with a free surface (not pressurized pipe flow).
  • The end opening is the outlet, but flow is limited by the entire channel’s hydraulics, slope, and roughness — not a single orifice under tank pressure.

If you plugged tiny head values into the 29.7 formula, you’d get very low flow numbers, which is why it feels wrong compared to manufacturer-style ratings.

Bottom Line

Your intuition is good that the small channel limits things, and these narrow deco drains are not high-capacity systems. 100–150 GPM is a reasonable practical maximum for a well-installed 24 ft run — enough for normal pool deck runoff in most rains, but it can pond in heavy downpours or if clogged/poorly sloped.

The 29.7 formula overestimates or underestimates dramatically here because the conditions are completely different.

So I replied with: I still think 150 gallons per minute is far too high. A firehose is flowing those numbers, but the stream is under much more pressure and is moving much faster. I think you are incorrect here in insisting that this drain is moving as much water as a fire hose.

So this is the answer I got:

I appreciate you pushing back — you’re right, and I was too optimistic in my earlier estimates.

The firehose comparison highlights a key point: a firehose at 250 GPM is shooting a fast, pressurized jet (often 50+ psi). Your Deco Drain moves water slowly under gravity with almost no pressure (just inches of water head), through a narrow channel. That makes high numbers unrealistic.

Better Data on Narrow Deck Drains Like Deck-O-Drain

Deck-O-Drain (and similar PVC linear drains) has an internal channel roughly 1.5–1.75″ wide by ~2–2.5″ deep. Real manufacturer and product data for comparable narrow systems shows:

  • Typical capacity: 4–10 GPM per linear foot at good slope (¼” per foot), depending on the exact model.
  • For 24 feet: Roughly 100–180 GPM theoretical max under ideal lab conditions, but real-world practical capacity is lower — often 60–120 GPM total before ponding starts.

Many similar slim drains rate even lower:

  • 1.25″ channel examples: ~4.2 GPM per foot → ~100 GPM for 24 ft.
  • Stegmeier Frontier-style: Up to ~9.6 GPM/ft in some tests.
  • Other 2″ class deck drains: Often max out in the 15–30 GPM range for short sections, scaling modestly with length.

The outlet pipe (usually 1.5″ PVC) frequently bottlenecks first at around 40–70 GPM under gravity.

It’s still wrong. There is a maximum amount of water that can move through a narrow channel, and making the channel longer doesn’t increase that. A mile long Deco drain isn’t going to move 52,000 gallons per minute. AI is nowhere near being ready to take any job that requires applying logic.

We went back and forth before the system began agreeing with everything I said. AI isn’t ready for this. This is why I no longer pay for AI access.

In case you are wondering, the nozzle formula is:

Flow equals 29.7 times the square of the diameter times the square root of the pressure.

Q (GPM) ≈ 29.7 × d² × √P, where d is the diameter in inches and P is nozzle pressure in psi.

This is a formula that I know well from my firefighting days. That’s why flows of 200+ gallons per minute were seeming far too high.

By Divemedic, ago

Flooded

This is a story of me afro-engineering a solution to some flooding that happened to my rear lanai. Now that there is a pool behind the house, what was our back porch has been closed off by an electric hurricane screen. There is some outdoor furniture and a TV in there, and it now serves as a sort of “Florida Room” and a place to store outdoor items when a hurricane comes. More on that in a different post.

We had a thunderstorm come through on Saturday, and it was a fairly strong one. We got just over 3 inches of rain in less than 45 minutes. That caused a bit of an issue. When we put the pool in, the contractor put a drain in place that lies at the end of the pool deck closest to the house. It looks like this.

That is just a slot in the concrete about 2 inches wide and 4 inches deep. It discharges on both sides of the slab. Right above where that discharges, the downspouts from the gutter discharge. I dug a trench at that point, and ran a 4 inch corrugated pipe that runs about 20 feet back from the house. At the end closest to the house, it looks like this (pictured is not mine, it’s from the Internet):

The discharge was one of these valves.

When the pipe fills with water, the weight of the water causes the valve to open. Well, as near as I can tell, the rain was coming down so hard that the drains were quickly overwhelmed, the area near the inlet to the drain pipes was soon underwater, and this caused a backup that flooded my rear lanai with about an inch of water. The rug out there was saturated, but luckily it’s an outdoor rug, so a couple of hours and a fan soon dried it out, no harm.

While it was raining, I went outside to see what the problem was. It had been so long since we had gotten any real rain, everything was clogged with dead oak leaves: the downspouts, the intake drains, all of it. So I cleared the leaves out, but that didn’t help a lot, and got me bitten on the hand by a rather large, angry spider that had been nesting in the leaves.

I spent Sunday digging up the ends of the drain pipe, and I replaced the intakes with this:

Since it is taller and not flat like the old ones, the hope is that this grate can handle more water AND is not likely to be clogged with leaves. Then I also replaced the discharge valves with these.

I am hoping that this will be large enough to allow more flow through the pipe. According to my math, a 4 inch corrugated pipe that is 20 feet long with a 1 inch drop every ten feet should be able to move about 75 gallons per minute. I have two of them (one on each side of the house) so I should be able to drain about 150 gpm.

Also according to my calculations, a rate of 3 inches of rain in 45 minutes is about 30 gallons per minute. This system should be able to keep up now, if I can keep it free of leaves. I guess we will find out next time we get a good rain, which in Florida is about once a week or so.

Keeping water out of the house is important, and no all prepping is sexy. Hope this helps someone else.

By Divemedic, ago

Energy as a Weapon

Protesters using energy as a weapon:

Sonic energy: Screaming in your ear with a bullhorn, blowing a loud whistle inches from your ear, using canned air horns, etc.,

Laser energy: Shining lasers into people’s eyes

Should be treated like any other weapon, and it will be if it is done to me. Pepper spray at first, then more aggressive as they escalate. I am over this kind of crap.

By Divemedic, ago

Summer Starts

Summer is defined as the warmest season of the year, occurring between spring and autumn. It features the longest daylight hours and the year’s highest temperatures. I also know that summer begins on the summer solstice (around June 21 in the Northern Hemisphere and December 21 in the Southern Hemisphere) and ends on the autumnal equinox. However, I don’t think most of us look at it that way.

It’s the warmth that makes a summer, and in Florida our summers are long, hot, and feature afternoon thunderstorms. For those reasons, I have my own definition of the beginning of summer. Here is Sector Ocho, summer is the first day of the year where the temperature doesn’t go below 75 degrees Fahrenheit (that’s 24c to those of you in countries using the metric system).

I have a personal weather station in my backyard that I use as my official measuring station because I don’t believe Florida’s numbers. My weather station is one of these. It’s located in my backyard in the middle of a clearing with the nearest block to wind (a tree) being at least 50 feet away.

Anyway, the first day of summer has arrived, and it was yesterday, May 25. Our low temperature for the day was 75.6 degF. Summer started this year a full 12 days later than it did last year. Our dewpoint right now is 75.8 degF.

The reason for this, is that the low temperature can’t go any lower than the dew point. At that point, any further energy lost from the atmosphere is spent condensing water vapor, not reducing the temperature. When the dewpoint is at that point, the air starts becoming thick and the afternoon rains begin. If you have ever been in Central Florida during the summer, you know that it rains virtually every afternoon. That’s where we are now. Summer is here.

The dew point temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. At 100% relative humidity, the dew point temperature and the air temperature are the same, and clouds or fog can begin to form. While relative humidity is a relative measure of how humid it is, the dew point temperature is an absolute measure of how much water vapor is in the air (how humid it is). In very warm, humid conditions, the dew point temperature can reach 75 to 77 degrees F, but rarely exceeds 80 degrees.

Dew point is the best indicator of comfort in a hot climate. Once the dew point of the air exceeds 66 degrees Fahrenheit or so, the air begins to feel hot and uncomfortably stuffy. The reason for this is that your perspiration cannot evaporate to cool you off.

The dewpoint here will remain high from now until summer breaks in late September.

Here in Florida, there are 4 seasons:

Hot: March through May
F’ing Hot (Also known as Hurricane season, and in Orlando, tourist season): June through mid September
Still Hot: Mid September through Mid November
Snow Bird: Mid November through February

The people who live here know that anything needing to be done outside between May and September is best done before 11 am, when the thermometer typically breaks 90 degF. That’s why Floridians usually mow the grass starting at 8am. The combination of heat and the inability to shed heat through evaporation is a deadly combination. Beginning today, you get your outside work done in the morning then stay in the air conditioning until at least 4:30 in the afternoon when the afternoon thunderstorms come calling. That is what we do from the first day of summer until about the middle of September.

That’s why having a pool is such a great idea. My pool is a nice 84 degF throughout the summer, and it’s the only way to be outside while the “feels like” temperature is more than 90 or even 100 degrees.

By Divemedic, ago

Propaganda

Propublica is a leftist rag spending a lot of it’s binary ink bitching about guns. The issue I have is in how they deliberately frame and distort facts in order to advance their agenda. Case in point is this headline:

This Gun Shop Stayed Open Despite Repeated Violations. Then A Chicago Cop Was Killed With One Of Its Guns

So how did the gun wind up in the hands of a criminal? Olivia Burgos bought the 10mm Glock handgun from Range USA, in Merrillville, Indiana, on May 27, 2024, by lying on an ATF form about why she bought the gun, where she lived, and about her addiction to illegal drugs. She admitted to buying the gun for her boyfriend, who gave her the money for the gun and was a convicted felon who was not allowed to buy or possess firearms. It’s unknown how the gun made it from the boyfriend to the cop murdering criminal.

The story spins this into an indictment of the gun store itself, claiming that this one gun store had been cited for “serious compliance failures on multiple occasions” by the ATF. One thing that’s important to remember is the chain of stores in question have 50 locations in 14 different states. In other words, this isn’t a gun store, it’s 50 gun stores. There is no mention of just how many citations were issued, nor the severity of most of those issues. The ones that were mentioned are:

  • The Merrillville store faced revocation of its license following a 2022 inspection that determined a background check was missing for one sale. The ATF later rescinded the citation after the store provided proof that the background check had actually been conducted. In other words, not a violation.
  • In 2021 at the store in Dayton, the ATF determined an employee sold a firearm to a person who failed a background check, records show. Company representatives admitted to the agency that the employee had failed to follow store policy and “missed the appropriate connections” concerning illegal sales, despite training.
  • The next year in Lewis Center, an ATF inspector found that a sales clerk had falsified records of a gun sale after accepting an expired conceal-and-carry permit in lieu of conducting a background check

The cop killed that supposedly spawned this article? Yeah, the gun used in the April 26, 2026 murder was in fact sold by Range, USA. In 2024.

Authorities said Bartholomew and another officer transported robbery suspect Alphanso Talley to the hospital April 25 after he claimed to have swallowed narcotics. Prosecutors said Talley pulled a hidden handgun from beneath a blanket while preparing for a CT scan and opened fire on the officers before briefly escaping custody.

So how can you lay this at the feet of the gun store? How is a gun store to know that the woman buying a gun is not going to give it to her drug dealing boyfriend who will soon sell the gun on the black market before two years later, it eventually winds up in the hands of a murderer that kills a cop?

Everyone knows there is no way for the gun store to know this. That isn’t the point. This is being used as some sort of ‘gotya’ to a large firearms retailer. This retailer has 50 store locations- actually, they are each required to have their own FFL, so we are really talking about 50 separate gun stores. What is that? 100,000 guns per year in those 50 stores?

The insinuation of this article is that Range USA is somehow deliberately selling guns to criminals. They don’t come right out and say that, because it isn’t true and they would likely get sued for it. So instead they frame the facts in such a way as to encourage the reader to make that connection themselves. It’s one of the three ways to tell a lie, according to Robert Heinlein:

  • lie with a straight face; anybody with enough gall to raise on a busted flush can do that
  • The first way to lie artistically is to tell the truth — but not all of it.
  • The second way involves telling the truth, too, but is harder: Tell the exact truth and maybe all of it…but tell it so unconvincingly that your listener is sure you are lying.

In leaving out the important details, they are misrepresenting the facts, and this is a form of lying. If you have to lie in order to make your point, perhaps your point isn’t worth making.

By Divemedic, ago

Data Driven

One of the things I am drawn to, and quite skilled at, is processing data. It’s why I enjoyed operating a fire truck, and it’s also why I like my job in medicine and enjoy the technical end of SCUBA. I would probably been pretty good at engineering. I love processing data and doing math in my head. I also enjoy having a good tool that will make that job easier.

Enter dive computers. These machines take all of the guesswork out of diving. Traditionally, divers would use a table where the maximum depth and total dive time were looked up on a table that would tell you the maximum time you could be underwater. This is called “square profile” diving. The table assumes you descend from the surface to a set depth, remain at that depth the entire dive, then return directly back to the surface. In reality, no one dives like that.

A dive computer uses a mathematical model to calculate how much Oxygen (and other gases) are in your tissues, then uses that to tell you what you need to do in order not to get the bends. It resamples the factors of the dive every 30 seconds.

That’s one of the things that I can’t understand about this diving accident. The diving computer would have warned them:

  • that they were approaching the no decompression limit once they had been under for about 7 minutes at a maximum depth of 160 feet. It would beep and flash.
  • When they reached 187 feet, they would have gotten another set of beeps warning them that the oxygen was at the maximum safe limit of 1.4 atmospheres of pressure
  • Most computers have a depth alarm that would have warned them about exceeding depth limits
  • Many computers have turnaround alarms that will warn you when you have used a third (or some other programmable amount of your air) of your breathing gas
  • Many dive computers would have had their models exceeded and would go into “violation” mode. There are more alarms here, and the computer only functions as a digital set of gauges after that point.

In short, there is no way that dive was an accident, and that is not even considering the stupidity of swimming that far into a cave. It always astounds me that someone will pay a thousand dollars for an expensive piece of gear that’s designed to save your life, then will ignore that device. The cheapest dive computer can be bought for less than $100 (although I wouldn’t bet my life on cheapest.)

My dive computer cost me well over $600, but it is obsolete and no longer for sale. If I were to buy one today, I would want a gas integrated console computer that can handle multiple gas mixes on one dive. The small wrist ones aren’t readable by this old man’s eyes- the numbers are too small on the display and I don’t want to wear a prescription dive mask.

So with that being said, I would want:

  • gas integrated
  • nitrox capable to 100%
  • multiple gases on one dive

With that, I my research settles on these:

  • Apeks DSX Dive Computer:The nice thing about this one is it would let me upgrade to trimix if I decide to do that in the future. It’s pricy though: $1200. Also, the connection to your tank is wireless, and that means sometimes losing the signal and not knowing how much pressure you have left.
  • Mares Genius: This one is cheaper at $800. Still has the wireless connection issue.
  • Oceanic Pro Plus X: This one solves the wireless issue, but it only handles nitrox to 50% and can’t do trimix. It’s also pricy at $1200.

I’m sure there are others, but those are the ones I would consider.

The disclaimer: I don’t advertise, and receive nothing for my reviews or articles. I don’t think that I ever will. I have no relationship with any products, companies, or vendors that I review here, other than being a customer. If I ever *DO* have a financial interest, I will disclose it. Otherwise, I pay what you would pay. No discounts or other incentives here. I only post these things because I think that my readers would be interested.

By Divemedic, ago

The Score

Here are the lists of assassination attempts against prominent Republican figures:

  • June 14, 2017 — James Hodgkinson, a left-wing activist, opened fire on Republican members of Congress
  • July 13, 2024 — Butler, Pennsylvania rally (Thomas Matthew Crooks). Trump was grazed in the ear.
  • September 15, 2024 — Trump International Golf Club, Florida (Ryan Wesley Routh).
  • July 2025, Armed attacks in Alvaredo and McAllister Texas. 
  • September 2025, Charlie Kirk was murdered
  • January 2026, a man broke into JD Vance’s private home in Ohio
  • February 2026 – Mar-a-Lago perimeter breach (Florida)
  • April 25, 2026 – White House Correspondents’ Dinner (Washington Hilton, DC)
  • May 4, 2026, near the Washington Monument on the National Mall in Washington, D.C., a man shot at the Vance motorcade.
  • May 23, 2026– A man attempted to shoot his way into the White House while the President was working in the Oval Office

I think there is no doubt that the left is engaged in hostilities. I also think, but of course can’t prove, that a significant portion of the Federal government itself has picked sides and is part of the festivities. Note that I have only included actual attacks in this list, not mere threats or talk.

By Divemedic, ago