Stern Ramps, a Scientific Study

Earlier we talked about the decision to specifically exclude use of a stern ramp in the specifications for the Offshore Patrol Cutter, “No Stern Ramp for Boats on the OPC-Mistake?”

I recently found a study that addressed this question. It’s conclusions seem particularly applicable to the Coast Guard:

The inclusion of a stern ramp has advantages in terms of  deployment and recovery speeds, but ultimately a stern ramp lacks availability in the higher sea states in which a davit is still capable of operation. The stern ramp availability is driven by sill depth and pitch motions, whilst a davit needs to consider a range of constraints associated with the environment, including pendulum effects, hoisting speed and the safety of deck crew.

Hence, a vessel designed to operate in benign to moderate sea conditions and requiring rapid boat response times may be appropriate for a stern ramp, as illustrated by their use mainly in coast guard and smaller patrol vessels. A vessel operating in higher sea states such as offshore environments, including conducting MCM and environmental assessment may select davit arrangements, accepting the increase in handling procedures to gain a greater environmental envelope. A flexible, multi-role naval vessel is therefore likely to err towards the later, because of  its greater flexibility and sea state envelope. A mixed solution may offer a compromise between these but suffers from the need to find space for both systems and requires training to cover several deployment methods, although the rapid response would be beneficial when operating in constabulary missions and may be an advantage to consider. In this case, the stern ramp is the secondary method of deployment and the mission space would be located midships with the davit system(s).

They also found that the relative success of stern ramps varied with the size of the “host” vessel, with it becoming more problematic as the size of the host vessel increased relative to the boat to be launched and recovered.

Late addition–Not sure why I did not link the original source when I posted, but here it is: Boat Launch and Recovery – BMT Group

4 thoughts on “Stern Ramps, a Scientific Study

  1. All that is what I have been saying for years now. Stern ramps NEED bigger hulls to accept there space and weight.

    When one adds the cost of installation and ability to vary a davit systemt to fit other or future cutter boats, using davits makes sense. What would make even more sense for the USCG is to buy davtis specific the the NEWER cutter boats and install those on older cutters.

    And there are many vessels similar to OPC and FRC which have two boats in davits.

    Now IF the USN would just wake up and put MORE of its boats in davits and less in wet well docks?

  2. Pingback: Philippine Navy Frigate Program: An OPV by any other name? | Center for International Maritime SecurityCenter for International Maritime Security

  3. Pingback: Boat Stern Launching Systems | Chuck Hill's CG Blog

  4. Pingback: New French Patrol Boat | Chuck Hill's CG Blog

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s