To all intents and purposes this is a sound-looking engine bracket. But take a good look at this ‘hidden issue’ and what to look out for on your boat.
This following account relates to one of my charter Luggers, operated by Dragon Drascombe in the South Ionian Sea this past summer of 2022.
Lugger Ellie has been a part of my Lugger fleet since 2017 and seen more than 1200 hours of engine use over this period of charters, with these 4 stroke engines hung on the Iroko transom bracket.
It has always been a concern of mine that these heavy engines are supported by the transom bracket and just 4 x 10 mm bolts connecting it to the boat transom moulding, even though I check on the nut tightness regularly.
On a cleaning and maintenance day this past summer I happened to notice a movement in the top of the transom board when the engine was put into forward gear, the bracket ‘dipped’ back from the hull moulding slightly. I also checked with the engine off by pulling the top of the engine case back and yes, there was movement in the Iroko bracket itself.
Hmm this is not good!! Potentially could result in a serious problem. Out offshore under engine with lots of power required to get back in gusty, heavy windy conditions, and the thrust of the engine could rip the bracket off its two top bolts. Not very clever at all. So, it was a case of diving inside the Lazerette and removing the 4 nuts and washers, remembering it’s in the South Ionian Sea at 38C plus in the boat yard!
It’s a procedure for a whippet, lying on one’s side on the floor of the narrow cramped Lazarette with both hands outstretched removing the nuts off the threaded bolts, then wriggling back to extricate one’s body from the opening of the Lazarette in order to straighten up. It’s a job I’ve done on numerous occasions when rebuilding Luggers in Wales, but not in tropical temperatures.
So what did I find one might ask?
These clearly show the enlarged two top holes in the glass fibre moulding of the transom which have been eroded by the movement and pressure from washer behind.
The lower holes had not been subjected to this wear, it’s the weight of the engine combined with the thrust from the long leg of the engine that puts so much pressure and leverage on the two top bolts.
One significant observation was that the thickness of the transom moulding in the area of contact with the engine mounting bracket was varying from 2 to 5 mm only, very thin indeed for such a heavy engine to be mounted on, given the movement created by the thrust of the engine.
One could cut a block in this enlarged area behind as a packer then add a bigger washer!! On reflection this would only be a temporary solution.
The long term solution was to not only affect a glass and resin repair but to add strength and backing support to the inside of the transom moulding, it’s clear that the thickness of this area is not sufficient and well below a safe and acceptable standard.
Here we start with two sections of 12 mm marine ply, the width and length of the internal face of the transom moulding and well oversize strips of heavy weight chopped strand mat. This accompanied by the requisite resin, containers and brushes to wet out the mat.
We now need to bond these ply packer / strengthening sections to the inside face so they are secure whilst applying the bonding glass mat and resin to them, with lots of overlapping onto adjacent areas of the deck moulding.
Always allow adequate time for the resin to cure, remembering one has to get back into this cramped and confined area to cog up the nuts and holding washers. The fumes that this Polyester resin omits are quite significant, so be careful!
With the engine bracket now in position, I have added a different bracket, the original has signs of stress cracks between the 2 top bolt holes, it’s now a matter of drilling through the Iroko bracket and then through the original glass fibre moulding plus this additional marine ply packer support which has been glassed in. You will note the extra large ‘Penny ‘ washers that I have used to spread the load and pressure.
For future reference, I will be working through my charter Luggers and adding this modification to the inside of the hull moulding. Also, my future rebuild of Luggers will include this additional modification.
When I get orders in from Lugger and Longboat owners for a replacement Iroko transom bracket I will be advising them to carry out this modification, and these two marine ply packers / strengthening I will now have in stock as a standard part at no extra cost to the transom bracket.
All’s well that ends well, but this could have been a serious issue for my Lugger charter clients in the South Ionian Sea.