Workability & Contract
Set limits per activity — transit, standby, MBES, crane — and SeaData marks every hour workable, near the limit or not. Calm spells shorter than your minimum window don't count.
Offshore workability forecast
Know your weather window before you mobilise.
SeaData checks wave, wind, current and visibility against the limits of your vessel and your contract — hour by hour, 48 hours ahead, from the best forecast models for your position.
Demo runs in your browser, no account needed. Built for survey, offshore wind and marine contractors.
3 of 4 activities workable now. Crane: next window in 11 h.
Average of the best 3 models per quantity · visibility: lowest model · example data
workable
near the limit
limit exceeded
window too short
Hs1.38mavg of 3 wave models
Wind @10 m9.6m/s1 h mean, 3 models
Current0.62m/stotal current, 3 models
Visibility7.4kmlowest model counts
What you get
One answer per activity, not another weather map.
Weather apps tell you what the sea does. SeaData tells you what it means for the job on your deck.
Models, ranked
ECMWF, ICON, HARMONIE, DINI, EWAM and more — side by side, ranked for your position. You see which model leads and why, and ensembles give the chance of staying within limits.
1HARMONIE2.5k
2DINI2.5k
3ICON-D22.2k
4ICON-EU6.5k
5ECMWF9k
Tide & current
Total current from Copernicus Marine, DMI and Rijkswaterstaat models, tide from FES and harmonic stations — the numbers a hydrographic survey plan actually needs.
Reporting
A weather report you can actually send.
One button turns the forecast into the report the job needs — on screen, as a PDF, or by e-mail. Not a chart to interpret, but a written answer with the numbers behind it.
The running day and the day after
Pick a technique from your own contract table and SeaData reports on the window from 00:00 UTC onwards, 48 hours long. It says what is over the limit and by how much, which quantity is holding you back, how long the adverse weather still lasts and when work can resume — and how much the models disagree about it.
Three views, one report
A status band of 48 hourly blocks, a meteogram per quantity with every model as its own line, and a limit ladder where everything stands as a percentage of its own limit against one 100 % line. Screen and PDF are built from the same facts, so they cannot say different things.
on screen · PDF · e-mailHow sure is it?
The ensembles — ECMWF ENS and ICON-D2-EPS — give each period a confidence: high, moderate, low or very low. No ensemble for your position means the field stays empty, never an invented number. And you can run the report for any three-hour moment in the window, not only for now.
confidence from 50 + 20 membersYour own weather supplier can join in: upload the DTN, StormGeo or Infoplaza PDF your contract obliges you to use, or have it e-mailed straight to SeaData from your own address. Once you release it, it is drawn as an extra line next to our models — it never changes the go / no-go.
48 h from 00:00 UTCper techniquePDF for printe-mail
Make it yours
Your sites. Your ship. Your data.
SeaData works with what you bring: the areas you work in, the vessel you work from and the sensors you already have.
Your own areas
Upload survey lines, work sites, cable routes or a wind-farm layout. They appear on the chart as your own layer, switched on and off per area and drawn to true size.
KMLShapefileTXT / CSV points
Your own vessel
Enter dimensions, draught and thrusters, and upload the general arrangement as top and side view. Workability then calculates with your ship, not a generic hull.
DXF top viewDXF side viewmax 5 MB
Two ways onto the chart
Everything starts with a position. Near the coast a shore station hears you and AIS does it by itself; further out, or when you want more than a position, your vessel can send its own.
Via AIS
Nothing to install. Position, speed and course, as often as a shore station or satellite picks you up — minutes near the coast, longer offshore, and quiet where no one is listening.
included · no setupVia the API
A small program on board sends over ordinary https, outbound only — every six seconds, anywhere with a connection. And it carries what AIS does not: heading from the gyro, roll, pitch and heave, wind, pressure and temperature, from the sensors you already have.
your API key · port 443Both at once is the normal setup: your own feed goes on top, AIS stays underneath as the fallback. Switch the program off and the vessel falls back by itself.
https · port 443NMEA 0183every 6 syour API key
Your own measurements
On requestWeather buoys, Waveriders, meteo masts, ADCPs, tide gauges: if you can deliver it, we can show it. Your readings appear on the chart as your own stations and next to the model forecasts, so you see how well each model fits your site.
Tell us what you measure and how it arrives. We connect the feed for your account.
CSV / TXTAPI or FTP feedDatawell WaveriderMeteo mast · ADCP
On deck
Your account, in your pocket.
Sign in on your phone and SeaData opens as a phone view: the answers you need on the bridge or the back deck, from the same models and the same limits as on your desktop.
- Now
- Hs, wind, current, tide and visibility at your vessel, with +3, +6, +12 h and the 24 h maximum.
- Contract
- Go / no-go per activity against your contract limits, and when the next window opens.
- Workability
- Your saved vessel, calculated for the moment you pick.
- Tide
- Curve at your position, next high and low water, and the nearest port: measured against predicted.
Put it on your home screen
- Open seadata.online on your phone and sign in.
- iPhone: tap Share → Add to Home Screen. Android: tap ⋮ → Install app.
- SeaData opens full screen from its own icon, like an app. No app store, no updates to install.
The phone view is part of your account and is for reading. Vessels, limits, drawings and areas are set up on the desktop. Tablet view is coming later.
MPV Northern Tide--:-- UTC
TransitStandbyMBESCrane
Waves · HsECMWF WAM
1.38m➤ 245°
Tp 6.8 s
+3 h1.42+6 h1.55+12 h1.91max 24 h2.26
Wind @10 mHARMONIE
9.6m/s➤ 230°
19 kn · gusts 13.1 m/s · Bft 5
Current · totalCMEMS NWS
0.62m/s➤ to 040°
1.2 kn · slack 19:40
Tide
+0.84m
HW 17:00
Visibility
7.4km
lowest of 3
SeaData
How it works
From vessel to go / no-go in three steps.
1
Add your vessel
Main dimensions, draught, thrusters and your DXF drawing, plus your own areas as KML, Shapefile or points. Every account starts with a ready-made demo vessel you can reshape into your own.
2
Set your working limits
Per activity: Hs, wind, current, visibility and the minimum window your job needs — straight from your contract.
3
Read the window
Hour by hour, 48 hours ahead: what's workable now, when the next window opens, and which quantity is holding you back.
Sources
Official models. Measured where we can.
60+ data sources, each with its age on screen. Measured, official or computed — always labelled.
ECMWF IFS · ENS
DWD ICON · ICON-D2-EPS · EWAM
KNMI HARMONIE
DMI DINI · DKSS
Copernicus Marine NWS · IBI · MED
Rijkswaterstaat DCSMv7 · measurements
Met Office NWS
Météo-France AROME · MFWAM
FES2014 tide
SWAN on demand, nearshore
Offshore platforms METAR · in-situ
What it is not: SeaData supports planning. It does not replace the master's judgement, your vessel's own operating limits or the contract itself — and every number tells you where it came from.
See your own window in two minutes.
Open the demo, drop the vessel on your site and set a limit. No account, no install.