# Questions for the experts: IMO numbers and tug horsepower ratings?

I have a couple of lingering questions I always ponder when I come across these topics. I sure someone here can answer them for me and would provide stimulating conversation.

question #1
Why does some vessels like crew boats and other smaller craft don’t have an IMO number yet some do? Is an IMO number issued or requested? does it make any difference in insurance coverage or stuff like that?

question#2

How can a tug company rate their tug’s horsepower so high when I know darn well the engines have half the HP of what they say?

thanks for any input.

The answer to question #2 is pretty much just a Cajun thing on the left/right coasts it’s true to form as far as power goes. I guess down in the gulf if it’s got nozzles and it’s 4,000hp they consider it more hp because of the increased pull you would get from the nozzles so most of the time it seems it’s “hypothetical horsepower”

Regarding #2. It is based upon two trains of thought.

The first is customers demand a boat with X,XXX HP. By damned the boat the office wants to market is somehow ‘rated’ at that number. How this happens is typical. Some office schmuck totals up all the engines on the tug ( MEs, gensets, washer dryer, radar scanner, etc etc) then rounds UP to the nearest thousand, then adds a thousand for mathematical errors, then adds another grand forknozzle bollard pull.

THAT is how HP ratings are assessed. (in the uninspected world of tugboats)

The freaking absolute best is the charterers are so fucking stupid they can’t figure this out! I believe it is Botruc that lists a triple screw cat boat at 8,000 HP and it. Has three 1800 HP (at best) engines in it!

The second is: On vessels that are classed, and actually have oversight (Solas, ABS, DNV etc) class societies actually determine this with input from the owner. There are some vessels that actually have lower numbers to keep below certain threshholds for manning and equipment reasons.

On my vessel for instance, I have genuine 4300 HP, but on each and every document she is listed at 4,000. Why? Because if it was rated over 4,000 it would fall under a different equipment requirement guideline. BUT, ABS and the office agreed on that number so away we go.

To answer question #1, a IMO number is required by SOLAS Regulation XI/3. Every propelled seagoing vessel over 100 Gross Tons is assigned a IMO number when the keel is laid. So the crewboats and smaller craft you refer to are all probably under 100 Gross Tons. There are a few other exceptions to the regulation such as fishing vessels, yachts, warships, etc.

Here is a link to a good article on the IMO Nr.

When needed, you apply for it from Fairplay, which admnisters the nrs. for the IMO. It doesn’t take long to get one. The form is about 1 page long.

[QUOTE=rshrew;80048]The answer to question #2 is pretty much just a Cajun thing on the left/right coasts it’s true to form as far as power goes. I guess down in the gulf if it’s got nozzles and it’s 4,000hp they consider it more hp because of the increased pull you would get from the nozzles so most of the time it seems it’s “hypothetical horsepower”[/QUOTE]
I didn’t realize Tom Crowley was a coonass. They’ve been calling the Invader class tugs 9000hp from day one.

Never sure where they got that number from they are what 7200hp at best? The boats were built down south.

IHP. Internal Horsepower. They add everything together then add a little more for good measure.

I primarily heard it called “Advertised HP.” I thought companies in the Gulf started this “liar’s hp” game. As I recall they called it “Gulf rated HP” at one time. They just forced everyone else to follow suit in order to compete. Apparently most of the people who were hiring tugs didn’t know any better and just took whatever they claimed for HP at face value. People who did know better started asking what the engines were and just ignored the advertized hp.

good example:

http://www.crosbytugs.com/acrosby.htm

2x Cat 3516 and rated 10,500 hp!

Dats some matt dais!!

Eben dere CAT says

http://www.depco.com/marine_engines/Caterpillar_3516%20DITA/Diesel/Rebuilt/Item-09821

Dere mus be sum powerful RADARS on dem dere tugs!

[QUOTE=injunear;80057]I didn’t realize Tom Crowley was a coonass. They’ve been calling the Invader class tugs 9000hp from day one.[/QUOTE]

They may sell them at 9k, but they are listed in the ABS Record at 7.2K. This comment comes up from time to time. Remember that marketing has very little to do with reality.