[QUOTE=c.captain;65215]HOLY SHIT! I wonder what caused that drydock to sink…it wasn’t that old! Crowley cannot be happy over this development.
As an aside, it has always amazed me that the 9000’s (INVADERS) were built with such little freeboard. When all tanked down there is no freeboard. Damed that must be some very wet boat in a big sea!
Do you realize that those boats are now almost 40 years old! Still they are classics in every sense of the word and still have plenty of “smash”!
As an extra note: all you brownwater GOM mariners notice the tall mountainous background covered with green trees…the wild west where the weather is wicked and the water is deep. None of your Belly Pass/Port Flushoon there! That’s real mariner’s country that is![/QUOTE]
I ran Invader class boats for a few years, as well as the similar Sea Swift tugs. They are wet, but fairly comfortable in all but the worst seas. I think that the least enjoyable ride I have ever had on one was back when we towed one of the SL-7s from Philly to New Orleans for a converson. 28’+ seas off of Hatteras made for a very slow, uncomfortable two days (one of which was spent going backwards thanks to the sail area of the ship being towed). Weather tight hatches all dogged down and the only water I saw inside the boat was up in the wheelhouse, coming in through those doors. For most conditions, I would dog down all doors but leave the top half of the Dutch door to the winch room open and had no problems. In calm seas, with the doors open, it was not unusual to find the odd flying fish in the engine room during the morning rounds.
As far as horsepower ratings, I do know that Crowley sold (and still sells) the boats as 9,000 HP. The 20 cylinder EMDs are rated at 3,600 HP a piece, so that doesn’t add up, of course. If you look at the Class entries for the boats, they are rated at 7,100 to 7,200 HP. Just because a company may sell the boats at one power rating does not necessarily mean that they are trying to skirt any regulations. More than likely, the registered HP will be accurate. When I worked with Crowley, I did ask about how the 9,000 HP was reached and was told that it was based upon calculations for a bollard pull. I still doubt it. As far as Korn Nozzles helping the Invaders, well that isn’t very likely since they are open wheel, as can be seen in the photo from Everett.
With regard to bollard pull, that is also a sales tool. So far as I know, there are no international regulations that require a vessel to have a bollard pull certificate. Now, just about all towing vessels do, since it is often a contractual requirement.
The Invader/Sea Swift design is pretty basic, and both classes of boats have some years on them now. What keeps them going is a pretty decent maintenance program (at least from my experience both with them and while at ABS) and the fact that there are only two ballast tanks that are only to be used in emergencies, so internal corrosion isn’t a real big issue.