Know she's fine before you drive to the marina.
Keelbell is a small 12-volt box that sends a text to your phone when the bilge pump runs more than usual, the high-water float trips, shore power drops or the battery sags. Ten years of cellular data and alert texts included (planned). No subscription.
The box reports over the cell network to our server, and our server sends the text. Including the texts for ten years is the plan.
$249 estimatedfounders $199 for the first 100
Refundable any time. Reservations aren't open yet, so nothing is charged. Keelbell is a concept in development: renders only, no ship date.
Yesterday 11:52 PM
Shore power lost at 11:52 p.m. House battery on its own now. · Slip C-14
Today 2:47 AM
Bilge pump ran 6 times since 1:10 a.m. It usually runs about once a day. · Slip C-14
Today 6:12 AM
Shore power restored at 6:12 a.m. Battery charging, 12.6 V. · Slip C-14
One box, next to the house battery.
Keelbell screws to a bulkhead through two flanges with stainless screws. Three cable glands on one end bring in 12-volt power, the bilge pump and float wires, and a shore-power sense wire.
Inside, the plan is a cellular radio, its antenna under the plain panel on the lid, and a small backup cell, so it can still tell you when the 12-volt side goes quiet.
The install we're designing for: power, ground, and one sense wire for each thing you want watched.
What it watches while you're at home.
Six things on a boat's 12-volt system, wired to one box. Each one triggers a plain-English text to your phone, sent from our server, like the examples below.
Bilge pump
Counts how often it runs and tells you when that's more than usual.
"Bilge pump ran 6 times since 1:10 a.m."
High-water float
A second float mounted higher. If water reaches it, you hear about it right away.
"High-water float tripped at 4:05 p.m."
Shore power
Texts when the dock power drops and again when it comes back.
"Shore power lost at 11:52 p.m."
House battery
Watches the voltage and warns you while there's still time to do something.
"House battery 12.2 V and falling."
Cabin temperature
A freeze warning for boats that stay in the water over the winter.
"Cabin 36 °F and falling."
Hatch or door
A simple switch on the companionway or a locker tells you when it opens.
"Companionway opened at 3:05 p.m."
Five years of alerts, one price.
Keelbell, with data and alert texts for those five years included (planned).
"...From $180 to $225 a year... Without it, its useless!"
- Siren 3 Pro$799.99 + $900 five-year plan$1,700sirenmarine.com, hardware and plan pages, Oct 6, 2026
- Siren 3$299.99 + $900 five-year plan$1,200sirenmarine.com, Oct 6, 2026
- NautAlert$399 + $149 a year$1,144nautalert.com, Oct 6, 2026
- Sensar Boat + Bilge$500 + $120 a year$1,100Panbo review, Feb 2024, checked Oct 6, 2026
- Roam Hub, on cellular$299.90 + $60 a year$600roamdevices.com, Oct 6, 2026
- Roam Hub, on your own Wi-Fi$299.90, no plan needed$300roamdevices.com, Oct 6, 2026
- Keelbell (estimated)$249, 10 years of cellular data included$249Founders price $199 (est.) for the first 100. Not for sale yet.
Roam is the closest rival, and it's a good product. Over five years on cellular it comes to about $600, which is $351 more than Keelbell's estimate. On your own Wi-Fi Roam costs $299.90 with no plan, and that's a fair choice if your marina's Wi-Fi reaches your slip. Keelbell has no Wi-Fi; it only uses cellular.
Hardware plus the cheapest plan that covers five years, rounded to the dollar, before tax and extra sensors. Prices from each maker's public website on October 6, 2026, except Sensar (Panbo's review). Roam's $299 bundle at Blue Marine includes a float switch, battery sensors and GPS; what comes in the Keelbell box isn't final.
Turn it over. Then see it at real size.
The 3D model is built from the same CAD as the render. On a phone, "See it at real size" puts it on your console or bulkhead.
Dots mark: the 3 cable glands, the stainless flange screws and the panel over the cellular antenna.
Specs, and what's still a target.
There's no working prototype yet, so nothing here is measured. Target means a design goal, Planned means a part or supplier we've chosen, and Estimate is arithmetic.
What it senses
- Bilge pump
- Counts pump runs and run time; alerts when it runs more than usual Target
- High-water float
- Separate float input; alerts the moment it trips Target
- Shore power
- Sense wire; alerts on loss and on return Target
- House battery
- Voltage; low-voltage alert Target
- Temperature
- Cabin freeze warning Target
- Hatch or door
- One contact input for a magnetic switch Target
Alerts
- How you hear
- A text message to your phone, sent from our server; included for the 10 years Planned
- If it goes quiet
- "Device offline" alert when the unit stops checking in Target
Connectivity
- Network
- The LTE-M cell network, NB-IoT where available. Alerts need coverage at your slip Planned
- Cellular module
- Nordic nRF9151 (the module is PTCRB-certified; Keelbell itself is not certified) Planned
- Data plan
- Prepaid IoT SIM in the box: 10 years, 500 MB. Its small SMS allowance is only for the box talking to our server Planned
- After 10 years
- Renew for about $15, or it stops sending Estimate
- Wi-Fi
- None in v1 Decided
Power and body
- Power
- 12 V DC from the house bank Target
- Backup
- Small internal cell to report a 12 V loss Target
- Body
- 112 × 78 × 35 mm (4.4 × 3.1 × 1.4 in), ASA plastic, gasketed lid Target
- Certification
- FCC and carrier certification of the finished unit, before any sale Planned
What it won't do
- It won't pump water, stop a leak or switch your bilge pump on. It only tells you what's happening.
- It isn't a substitute for checking your boat, a working bilge pump, a marina watch service or insurance.
- It needs LTE-M or NB-IoT coverage at your slip. No Wi-Fi, no satellite.
- GPS position tracking isn't in the v1 plan. Roam has it, if that matters to you.
Where it stands today.
Dates are plans, not promises. We'll email the list when one moves.
- Oct 2026Concept, CAD and renders done. Talking to owners at the Annapolis boat shows.
- Nov 16, 2026Decide whether to build a prototype, based on the list and your answers.
- Winter 2026–27If yes: a bench prototype, then a few units on boats kept in the water at one or two Chesapeake marinas.
- Before any saleFCC and carrier certification of the finished unit.
- Ship dateNone yet. We won't name one until a prototype works and certification is booked.
Get on the list for the founders price.
- Estimated price$249
- Founders price, first 100$199estimated
- Cellular data and alert texts10 yearsincluded (planned)
- Reservation$20refundable, not open yet
- Ship dateNone yet
How the $20 reservation will work. It holds a founders-price unit and comes off the price. Email keelbell@burakali.com and we refund it in full, any time. Keelbell is a planned product and may not ship; if we don't build it, every reservation is refunded. Reservations open once we've confirmed payments. Until then, the list is the way in.
Join the list
One email when there's news, and first call on the founders price.
Thank you. That's everything.
What happens next:
- On November 16 we decide whether to build a prototype, using answers like yours.
- You get one email either way.
- If reservations open, you're first in line at the founders price.
Questions owners ask.
Is there really no subscription?
For ten years, that's the plan. The box carries a prepaid IoT SIM with 500 MB of data for ten years, which it uses to report to our server. Our server then sends the alert texts to your phone, and we plan to include those texts for the same ten years. The SIM's own SMS allowance is only for the box and the server; it isn't used for your alerts. We'll publish real data use once a prototype runs.
What happens after ten years?
You can renew the data for about $15 (our estimate of the provider's renewal price), or the unit stops sending. We'll email you well before it runs out. We don't say "lifetime", because it isn't.
Will it work at my marina?
If there's LTE-M or NB-IoT coverage at your slip, it's designed to work. Tell us your marina in the form and we'll check it before anyone pays anything.
Is Keelbell a safety device?
No. It's a notification aid. It doesn't prevent flooding, sinking, theft, fire or battery failure, and it isn't a substitute for checking your boat, a working bilge pump, a marina watch service or insurance. Alerts depend on cell coverage, power and correct installation, and can be delayed or missed.
How is it different from Roam?
Roam is good, it's shipping now, and it has reviews. It costs $299.90 plus $60 a year on cellular, or nothing a year on your own Wi-Fi, and it includes GPS. Keelbell is an estimated $249 with ten years of cellular included, but it doesn't exist yet. If marina Wi-Fi reaches your slip, Roam's free plan is hard to beat.
What does it connect to?
12-volt power from the house bank, the bilge pump's power wire (to count runs), a high-water float switch, a shore-power sense wire, and an optional magnetic switch on a hatch or door.
I run a marina. Can we try it?
If we build prototypes this winter, we want them on boats kept in the water at one or two Chesapeake marinas first, at no cost to the marina. Join the list and pick "marina manager" in step 2.
When does it ship?
There's no ship date. The plan above says what has to happen first. We won't name a date until a prototype works and certification is booked.
Is the reservation refundable?
Yes. Reservations aren't open, so no one has paid. When they open, the $20 is refundable any time, and if Keelbell isn't built, every reservation is refunded in full.
Who is behind Keelbell?
Keelbell is designed by Burak Unlu, a computer engineering student at Johns Hopkins in Baltimore (his own project, not a university one); the company behind it, pebl health inc., is named in the footer. What you can check today: every spec says whether it's a target, and the price comparison lists its sources. Questions, or to have your details deleted: keelbell@burakali.com.
Why I'm building it.
I'm Burak Unlu, a computer engineering student at Johns Hopkins in Baltimore, and Keelbell is my own project, not a university one. Boat-owner forums keep coming back to the same two complaints: monitors whose plans cost more every year than the box did, and monitors that went dark when 3G shut off. Keelbell is my answer to both: the plan is one box, one price, ten years of data paid up front. Today it's CAD and renders, not a prototype. If enough of you want it, I'll build it, and I'll tell the list honestly how it's going.
Burak UnluBuilding Keelbell in Maryland