IMPROVING A DIFFICULT ENGINE SETUP : 1GM10 ELLEBOGEN GT S40 MOUNTS
Sailboat: Ecume de mer 75, sailing in the Mediterranean near to Barcelona
USING 4 UNITS OF THE ELLEBOGEN GT-S40 (120450-06201)
The aim of this report we will explain the case of a user of a Yanmar 1GM10 that had high levels of vibration on a Ecume de mer 75 and the steps to fix the vibration problem.
We will start first describing the details of the Sailboat. The engine used on the boat is single cylinder Yanmar 1GM10. The boat measures 5,87 meters (19,25ft) in length and with a beam of 2,67m (8,75ft) giving it a total displacement of 1,814Kg (4000lb). the draft is 1.52m (5.00ft)
Designed by Jean Marie Finot and built by Mallard Shipyard in La Rochelle, FRANCE.
This Sailboat well maintained and properly stowed can accommodate up to 2 people in comfort.
INITIAL SITUATION OF THE ENGINE
|The owner of the Sailboat observes that the engine moves too much. After watching a video of Bricolaje nautico. He contacts Sergi Castelló the owner of Bricolaje Nautico Youtube Channel. Sergi decides take his car and go to see the engine, making the following video.|
|Fig 1. Video “Before”. Mounts show excessive movement.|
As it can be seen, the mount exhibits an excessive elasticity. At the same give force, the used engine mount has more deformation under the same given load. This is the reason why the engine shakes more. The engine has more movement because the engine mounts allow more deflection.
When the mounts have an increased stiffness the Resonant frequency (also called Fundamental frequency) increases following the below formula:
To avoid a Resonant situation, the Sailboat owner decided to increase the idle speed to have a better vibration isolation. See below image:
Nevertheless, the idle speed was so high that putting the transmission in gear was too harsh.
CHANGING THE STIFFNESS TO THE CORRECT VALUE
Based on the technical characteristics of the 1GM10 engine, such as weight, position of mounts and position of Cog, 4 mounts of the Ellebogen GT S40 were selected. The mounts have the following technical and dimensional characteristics.
VIDEOS “BEFORE” AND “AFTER”
|Customer was able to make a video of the situation of the engine with the new mounts. The sailboat owner was able to return to the precedent idle speed, having an excellent vibration isolation and low mobility of the engine.|
MORE INFORMATION ON THE GT mounts
The new Ellebogen GT mounts are universal marine engine mounts. They incorporate a failsafe interlocking metal part as shown on the below image.
|This feature allows them to withstand to high forces in traction.|
|The mounts have been subjected to severe fatigue tests allowing to have an optimum behaviour .|
The metal parts are treated with Zinc Nickel allowing a salt spray resistance of 760H to the red corrosion and on top of this, there is a double coat of PU black paint. This allows to obtain similar anticorrosive results to Stainless steel Aisi 304.
If you have a similar application or engine do not hesitate to contact us.