has a couple of sins.
(1) the engine bed is not connected to the hull at the turn of the bilge
. Instead, it is supported by a thin fiberglass
pan bridging the bilge. This thin structure has very little moment of inertia, therefore, little bending resistance, therefore it will deflect downward when loaded and will flex with engine vibration. Over time, the thin fiberglass sheet will loose its strength due to fatigue and the glass and plastic matrix will part company and you will be left with a floppy pan supporting the engine. The main flex points are where the pan attaches to the hull. The aft end is the main problem as the fwd end of the bed seems to be tabbed to the hull.
(2) The tank, located under the engine pan, is not accessible for cleaning
. You might have a clean tank or you might be full of water
and bug sludge. You need to relocate the tank, if at all possible, and provide accessible hatch
The only way to remove that tank is to either cut the engine pan out, or to cut the tank in pieces as you move it forward, assuming it is not fixed into position.
I would seriously consider looking for an alternative tank location so that you can ensure cleaning access. You have been lucky so far and perhaps you can continue to count on luck or you can address the issue. Builders are driven by cost and convenience and foist a lot of crap on the consumer. Welcome to the club.
The engine pan can be easily cut out with a multi tool or a cut-off wheel
on a grinder. It will take about 15 minutes and its done. It will take longer to protect against dust than to do the job. Cut the pan at the edge of the tabbing very neatly so that you can remount the pan in the exact same location.
Now very thoroughly solvent wipe all the surfaces to remove oil
and grease. Use appropriate ventilation and fire safety
procedures. Do this before grinding the surfaces so that you don't drive the oil
and grease into the fiberglass.
Then put a 30 grit sanding
disk on the grinder and clean up the surfaces in your engine room, removing paint
but trying not to cut into the weave of the roving too much. You now have a blank slate for reinstalling your engine PROPERLY. You will be making a lot of dust and will at this point curse me. Protect yourself and the boat interior
. Use a box fan on a hatch
over the engine room or cockpit
lockers to extract the dust and to make the environment
more livable while you do the deed.
Reinforce the existing pan by laying some additional layers of 'glass under the pan to stiffen it and also add some transverse stiffeners (rounded wood formers you can glass over). Add a few layers of 'glass, bed in the formers and add more layers over the formers. Make sure you don't create a conflict at the edge where it meets the hull and make sure that you protect the reference edge.
Replace the pan as described by a previous poster. Put the pan back into position using shaped wood blocking under the beds resting against the hull. Lay this blocking on some beds of thickened resin or multiple layers of matt and resin (if using polyester). Now re-tab the pan to the hull and tab the blocking to the hull and pan. Develop a strategy for prewetting the 'glass and laying it in place. The 'glass does not have to be continuous, you can use smaller overlapping pieces. You want at least a 1/4" thickness of material or more, do not skimp. Use thickened resin at inside corners to form a camfer to lay the glass against. Make sure that the blocking has rounded corners where you will be laying 'glass. Use a 2" chip brush, a small roller and an air bubble roller to tidy up your surfaces. When finished, your beds should be blocked securely to the hull in the original position and will no longer be susceptible to vibration and fatigue.
Grind everything smooth and use waxed gelcoat
to flow coat the surfaces. You should be able to remount the engine in the exact same location.
You can use either polyester (good), vinylester (better) or epoxy (best) resins. Note that you cannot use matt with epoxy. The better resins are stronger and have better adhesion. That being said, you can get away with cheap
polyester by increasing thickness and bonding areas. I often compromise by using vinylester but it is up to you to decide.
You don't have to be sophisticated with your structural analysis, this can be viewed as a dumb project
where you just make 'er thick because the weight does not matter and the materials are cheap
. It is more important to be neat so you don't cringe when you look at it.
If you have never done fiberglass work
, you should recruit an experienced assistant. It is not hard, but there are definitely tricks and techniques. If you can't find a helper, then practice before hand on practice pieces.