SWATH resistance predictions using Michlet

[AdmiralS]

This is why:
View attachment 207484

She ran aground and breached the 2 stbd side hulls. Was towed back to Louisiana, and declared an insurance write off.
That's the last I heard.



After a period of several years of "legality", she did successfully go into service.
But not for very long....leaving vessels hanging around ideal never used for years, does wonders for machinery



They are an extremely seakindly vessel, we sailed her through a typhoon...no issues at all...

Thank you, this was very helpful!

The puzzle pieces for me were either political or physics so that takes the mystery out of it and makes me feel much better!

 

[Ad Hoc]

Glad it helped to reassure you.

 

[AdmiralS]

Glad it helped to reassure you.

Would have loved to been aboard for the typhoon ride. Speaks testaments to how they handle.

The mechanicals are my second biggest concern.

Especially around the uniquess of the drive train and gear boxes not being off the shelf parts...

 

[Ad Hoc]

Would have loved to been aboard for the typhoon ride. Speaks testaments to how they handle....

A grainy still from the video we took, during the typhoon:

...The mechanicals are my second biggest concern.
Especially around the uniquess of the drive train and gear boxes not being off the shelf parts...

That was a concern to us when we designed her too. But the gearboxes we selected by Hundested, have been built-proof.
The are very agricultural, in the sense built to last - as their main drive trains are for fishing boats in the north and baltic seas.

 

[AdmiralS]

I am familiar with Hundested for their cpp's.

Are the CPP's Hundested as well?

 

[Ad Hoc]

....Are the CPP's Hundested as well?

Yes.

 

[jehardiman]

Tenaz has been sitting for almost 15 years which leaves a number of questions around why
The particular concerns are around stability and sea keeping and if they are a viable platform

Besides Ad Hoc's well informed reply on these specific vessels, there are a few things I learned about SWATHs during my design project and following the T-AGOS-19 and other vessels over the decades.

Properly designed and sized SWATHs are very seakindly, stable, and easily driven, however they have the following issues
a) They are structurally inefficient, they need more material for their given displacement and cost more to construct and maintain that structure.
b) They are displacement inefficient, they have a very limited "active" displacement and carrying capacity. Operate a SWATH off it's designed lines and it can be a mess.
c) Their machinery is more complicated than a similarly sized mono or cat main propulsion plant. This leads again to more up-front installation and maintenance costs.
d) Size...SWATHs are wide and deep for their displacement. This makes shoreside berthing and support cost greater.

So SWATHs can be the vessel of choice WHEN YOU ABSOLUTELY NEED WHAT THEY BRING TO THE TABLE. Otherwise, in the full economic evaluation, there are better choices. SWATHs have been, and always will be, a niche vessel.

EDIT: Went looking and noticed this.... SWATH Slice Vessel - Asset Deal Hub https://assetdealhub.com/product/swath-slice-vessel/ ....as is where is. $77K? With engines?

 

[BMcF]

We were selected by L-M to supply the steering/stabilization package for those SLICE SWATHs but were nudged out at the last minute because the parent company of our competition had them throw in a dramatic last-minute cost reduction that was too large for the project to ignore - and far too low for us to match. That turn of events ended up being a blessing, as the cost for them to perform on that project ended up being a huge overrun. No worries...we've had some very successful SWATH projects with Ad Hoc since then. ;-)

 

[BMcF]

Besides Ad Hoc's well informed reply on these specific vessels, there are a few things I learned about SWATHs during my design project and following the T-AGOS-19 and other vessels over the decades.

Properly designed and sized SWATHs are very seakindly, stable, and easily driven, however they have the following issues
a) They are structurally inefficient, they need more material for their given displacement and cost more to construct and maintain that structure.
b) They are displacement inefficient, they have a very limited "active" displacement and carrying capacity. Operate a SWATH off it's designed lines and it can be a mess.
c) Their machinery is more complicated than a similarly sized mono or cat main propulsion plant. This leads again to more up-front installation and maintenance costs.
d) Size...SWATHs are wide and deep for their displacement. This makes shoreside berthing and support cost greater.

So SWATHs can be the vessel of choice WHEN YOU ABSOLUTELY NEED WHAT THEY BRING TO THE TABLE. Otherwise, in the full economic evaluation, there are better choices. SWATHs have been, and always will be, a niche vessel.

EDIT: Went looking and noticed this.... SWATH Slice Vessel - Asset Deal Hub https://assetdealhub.com/product/swath-slice-vessel/ ....as is where is. $77K? With engines?

Used SLICE vessels go cheap! LOL. I was supporting some repair work on a windfarm SWATH CTV (one of Ad Hoc's) out of Esbjerg and we took leisurely drive up the coast on our day off...discovering the original Lockheed SLICE sitting in the water awaiting her fate.

 

[jehardiman]

Used SLICE vessels go cheap! LOL. I was supporting some repair work on a windfarm SWATH CTV (one of Ad Hoc's) out of Esbjerg and we took leisurely drive up the coast on our day off...discovering the original Lockheed SLICE sitting in the water awaiting her fate.

Apparently she was scrapped in 2019. Pretty good look at her 4 demi-hulls and props in the wiki picture BTW.
Sea Slice - Wikipedia https://en.wikipedia.org/wiki/Sea_Slice

 

[Ad Hoc]

Apparently she was scrapped in 2019. Pretty good look at her 4 demi-hulls and props in the wiki picture BTW.
Sea Slice - Wikipedia https://en.wikipedia.org/wiki/Sea_Slice

She was used at a windfarm CTV for a while, operating out of germany, last I heard. That was a few years ago.