Strut Keel Design and Engineering Grounding Forces

Indeed it is. Since the skeg/keel, for the yacht is essential!!

 

Thank you Ad Hoc here I made a drawing to illustrate the calculation of keel bolts following Larsson & Eliasson method .First Step calculation of the Reaction Force Moment at each bolt position Bolts from the first 25% of keel surface are to take care of the grounding load.
The modelisation in 3D and simulation of this geometry in the FEA gives us the reaction force at each precise location

 

Thank you all for your great input. I did advance quite significantly in my design & study of a side keel to take the load of light grounding as defined by Larsson and Eliasson at speed 8 knots but to break off at higher loads without damage to the hull composite structure. In the process I came upon this report about the RNLI boats Severn and Trent that were at that time loosing ther side keels . The article mentions the Severn side keels were redesigned to have two modes of failure: 1. Damage to the tip of the keel without the whole keel becoming detached if the boat hitting something hard 2. Detachment from the hull without affecting the watertight integrity of the boats when subjected to extreme loads. They say " calculations show the keel is able to withstand a horizontal point load of at least 27 tonnes on its base in the case of Severn that is 3/4 of the boats weight . Very interesting I would appreciate any feedback regarding RNLI boat side keels engineering. Were they bolted on ?
Very interesting the RNLI

 

From memory no they weren't.
We used to build these RNLI boats in our yard.

 

Hi AdHoc thank you for your kind feedback, I did myself serve with the Marine Engineering and Naval Architecture Department of the Royal National Lifeboat Institute at the headquarters and the new boat factory in Poole between 2014 and 2016, I am aware the tamar motorboat and the Severn were built in other boatyards and that boatyard must have been the one you mention above; I am highly admirative of RNLI and of your work; I did visit Berthon Boat Company that did building of the new Shannon Boats and I did meet the naval architect that designed the Shannon and he did introduce me to the boat . I do see the Shannon side keels are designed to break under load and I do see the inserts in the Shannon Hull Mold. I wonder if the internal structure of the Shannon side Keels is metal or fiberglass

 

The Shannon lifeboat side keels are designed to break under load at two failure stages :
first the side keels would " peel off " under a certain amount of grounding charge
and further they would completely detach at a high amount of charge so that the hull of the boat is undamages and keeps its structural integrity
It is said the design and engineering of Tamar Keels were made in cooperation with Lloyds register of Shipping wich also carried out calculations of the strenght of the keel and its attachemment to the hull
I find this concept of "peeling off keels " very interesting and it would be good to know if internal structure is fiberglass or metal. In this photo there is the side keel of a Severn Boat theat has been designed in conjunction with Lloyds

 

Thank you for your feedback
The Shannon lifeboat side keels are designed to break under load at two failure stages :
first the side keels would " peel off " under a certain amount of grounding charge
and further they would completely detach at a high amount of charge so that the hull of the boat is undamages and keeps its structural integrity
And here is a photo of the cantilever testing of the Tamar boat adhesion keel join. I woder if anybody did such tests ?