Stern Launching & Recovery of RIBs

[thebig C]

Should the new vessels have a stern ramp, for launching and recovering RIBs?

[thebig C]

deployment of boarding craft

Both items you discussed in your last post have already been covered on this site. Please read this thread in full.

Use the S***** F*******

According to Cdr. Mark Mellet, writing in An Cosantóir, small boat operations are the Irish Navy's niche capability. Stern ramps appear to be becoming the standard for patrol ships that frequently deploy boarding craft, so it is important that this facility be seriously considered for the new Naval Service patrol vessels. These ramps are said to provide safer launch and recovery in higher sea states, while requiring fewer crew. Having surveyed stern ramp operations in a number of countries, the US Coast Guard decided that the new Deepwater cutters will all have stern ramps. The report of that survey describes launch and recovery operations in detail,

http://www.nmri.go.jp/main/cooperati...erg_Cleary.pdf


(By the way, I could only find a couple of posts on the subject of stern ramps, which were not that informative.)

[FMolloy]

I thought the USCG had cancelled the Deepwater cutters.

[Goldie fish]

Yep. If he/she had read the other posts as I had suggested he/she would already know that.

God bless the search function. Amen.

If you search for the thread on the Customs Cutter, that is one of the few boats that use the stern launching ramp, but that works for a boat of its size. However for proper ships, the launch system as seen on Eithne and the P 50 class is far safer and more practical. Launching, and recovering a Rib from the stern requires the parent vessel to stop its engines. Have you seen the wash a twin screw ship at full tilt can churn?

[techman1]

wipe the cream from the whisks of the mixer??? no thanks perfer to wipe the side of the bowl!!!!

[thebig C]

I thought the USCG had cancelled the Deepwater cutters.

The Deepwater project includes three different types of cutter. The smallest of the three, the Fast Response Cutter programme, has run into trouble, but will probably continue in a different form. Other Deepwater vessels are not affected, nor is the USCG policy decision to opt for stern ramps.

Yep. If he/she had read the other posts as I had suggested he/she would already know that.

God bless the search function. Amen.

If you search for the thread on the Customs Cutter, that is one of the few boats that use the stern launching ramp, but that works for a boat of its size. However for proper ships, the launch system as seen on Eithne and the P 50 class is far safer and more practical. Launching, and recovering a Rib from the stern requires the parent vessel to stop its engines. Have you seen the wash a twin screw ship at full tilt can churn?

I guess you didn't read the USCG report yet....

[hptmurphy]

Given that the procurement of new ships is about to become a political foot ball. I think we will have to wait and see how this pans out.

The NS have very determined wish list and what these vessels will be opperated as or equipped with is only pure cojucture.

I agree with current methods of raising a lower boarding vessels from the water as it is far more flexible that the rear ramp thing...but only my opinion..time will tell.

[FMolloy]

I agree with current methods of raising a lower boarding vessels from the water as it is far more flexible that the rear ramp thing...but only my opinion..time will tell.

The opinion of someone who's served at sea counts for a lot in my book.

[Goldie fish]

The Deepwater project includes three different types of cutter. The smallest of the three, the Fast Response Cutter programme, has run into trouble, but will probably continue in a different form. Other Deepwater vessels are not affected, nor is the USCG policy decision to opt for stern ramps.




I guess you didn't read the USCG report yet....

The FRC and OPC are the only type in the deepwater Plan to include a stern ramp only. NSC has the same single point Launch system as we use.
Why are you advocating such a system?
What experience do you have in its use?
What advantages do you see over the single point launch?
What LARGE USGC cutters currently use the stern ramp method?

I noticed some details in the report you provided:

The longer the ship the higher the
accelerations and the greater the motions, limiting use
in higher sea states.

The ship speed for most launchings was
between 3 and 6 knots. This gives the mother ship
enough forward motion to maintain her course but still
slow enough for the RHIB to escape the stern wake
after launch.

All the small boats exhibited difficulty
navigating the wake and keeping the boat on a straight
in approach. The stern wake made it difficult to
maintain directional control of the small boat. As the
sea states increased, the wake effects worsened.

It is unusual that there are no conlusions to that report.

[ZULU]

Of my 10 years of effectively piloting small craft, namely RIBs (from 20hp to Twin 90hps to 250hp) in hairy seas sometimes, you never ever ever ever come up on the stern of a larger vessel thats on the move. It's so much easier and safer even at high spped (15kts) to come up on the lee side, put the nose into the hull of the larger vessel and either ride the trough or the back of the wave.

[thebig C]

just consider it

The FRC and OPC are the only type in the deepwater Plan to include a stern ramp only. NSC has the same single point Launch system as we use.

You're right, the NSC (now known as the Maritime Security Cutter, Large) doesn't have a stern ramp, in fact it has two...

Why are you advocating such a system?
What experience do you have in its use?
What advantages do you see over the single point launch?
What LARGE USGC cutters currently use the stern ramp method?

The new ships for the Naval Service will presumably have a lifetime of 30 years. It is therefore only common sense that in selecting the design of those ships, we should take into consideration both experience from the past and new technologies and developments of the present. I am only advocating that the question of stern ramps be considered.

I noticed some details in the report you provided.

Did you not notice the rest of the report?

[Goldie fish]

You're right, the NSC (now known as the Maritime Security Cutter, Large) doesn't have a stern ramp, in fact it has two...



The new ships for the Naval Service will presumably have a lifetime of 30 years. It is therefore only common sense that in selecting the design of those ships, we should take into consideration both experience from the past and new technologies and developments of the present. I am only advocating that the question of stern ramps be considered.

Did you not notice the rest of the report?

Am I missing a part of the report that has findings or conclusions, i.e the result of the review of international practice? I think you'll find that the "experts" on this site, that is those who use small craft in open seas as part of their occupation, have considered it, and rejected it. You need to explain why you think its a good idea, rather than quoting passage and verse from someone elses writings.

[ZULU]

Hehe. I'll bring you out in a 150hp 6m RIB and we'll come up on the stern of a Coastal tanker or if we're lucky a NS vessel thats underway. And then we'll see how easy it is to get into a ramp position.

The Customs cutter boys can only handle it at below 6 kts.

I've done a 4.5m RIB side recovery on a large civilian vessel at 15kts in force 4. Try that with a stern ramp and A) you'll end up on the port or starb'd quarter after missing it or B) nose dive with a bad wake/wave combo, fall over board and drown.

[hptmurphy]

Try it in the dark for real fun!

[thebig C]

experience

I think you'll find that the "experts" on this site, that is those who use small craft in open seas as part of their occupation, have considered it, and rejected it. You need to explain why you think its a good idea, rather than quoting passage and verse from someone elses writings.

I have a great deal of respect for the people here who have experience of launching and recovering boarding craft using side davits. But anyone who takes an interest in the development of naval ship design cannot fail to note the increasing use of stern ramps for this purpose. I would be very interested to hear from anyone who has personal experience of using stern ramps.

Deploying RIBs by stern ramps rather than by side davits is said to be

• safer
• quicker
• requires less crew

If that is true, then it would be strange if the Irish Naval Service failed to at least consider the possibility of including stern ramps in the design of its new patrol vessels.