Please name this Fiberglass structure used in place of "Stringers" for engine mounts

[captlloyd]

I’m seeing a lot of space aft of the engine for one or two new tanks.

[HopCar]

It looks like a Fred to me. That’s it’s name, Fred the Engine Bed.

[19thol]

are you sure the "bed" won't come out if you unbolt the motor mounts?

[captlloyd]

Originally Posted by 19thol

are you sure the "bed" won't come out if you unbolt the motor mounts?

Ah, sure look glassed in to me.

[LobeliaBlue]

I've always heard them called Bunkers*, and v. occasionally Sleepers -
but those are not just under the engine, they're large joist-like things
that usually run the length of the vessel on each side of the keel/keelson.

Stringers (to me) are the thin longitudinal battens that hold the ribs
in place before the skin or planking is laid up.

*british/canadian background, so ...

[billgewater]

Beds! Well that's put that to rest. Are they ever called "sleepers"? As in railway sleepers?

[LobeliaBlue]

from the Glossary of Boat Building terms at https://www.iims.org.uk/

Sleepers: Horizontal secondary supporting members which strengthen bulkheads
and similar vertical surfaces. In metal vessels they are called girders.

[Squanderbucks]

I’m not too excited about recommending keeping the original setup. The “pan” or tub portion seems pretty flimsy and the engine weight does not seem to be supported directly by any heavy structure. The engine mounts are not supported by anything solid.
I would ditch the molded tub and remove the paint along the sides of the real stringers just outboard where the pan fastens. Square up the surfaces with fiberglass Ind wood if needed. Then have either two long or 4 Shorter aluminum right angle mounts bolted in place. These are often made from 1/2” thick alum
Then put your engine mounts through bolted to the new aluminum brackets.

Much more solid and leaves you access to the new replacement tank in the future.

Examples of these types of mounts are shown for powerboat applications at Seaboard Marine ( submarine.com )

[Squanderbucks]

Typical aluminum rails for the engine mounts

[Pillroller]

What about a flexible water tank, i.e. like a bladder? you can put it into the old tank and fit a F.G. or painted, epoxied wooden plate over the tank. Only need to take out the horizontal bit between the beds and replace with bearer across at the front/back, to retain rigidity. Good luck.

[BenBowSirocco]

Based on the photos, which is really not much to go on, so this conjecture and opinion.

You might be served well just utilizing the hull as your tank. It appears you need two sides: top and front. Cut up the old tank in place and discard it doing your best to preserve a few pieces of the original tank tabbing. Suit up and prep and grind everything for 6" around the existing flanges (3" above/below).

You could then use a flat surface (mdf with plastic carefully stretched/stapled works wonderfully) and lay up panels using a 1/2 PVC foam coring. Laminate the top (1 layer 1700 biax in epoxy) flip the part and laminate the other side.

Then pattern your parts and cut out the patterns from the laminated foam core panels- bevel to fit the hull within 1/8" (ish). The top can be made of as many pieces as necessary, but the less the better.
Brush on an epoxy binder coat to hull and panels and then mix up fumed silica and epoxy into putty. Once binder coat is in its gel state, glue in each panel on all 4 sides very liberally and then tab the panels from the outside on every seem/joint that is exposed with 4" 1700 biax tape.

This method eliminates laminating the inside of the tank. Our boat is over 30 years old with 4 integral bilge tanks of polyester hull on three sides with zero issues. If you have fears of osmosis, follow West Systems guidelines and simply roll on 6/7 coats of epoxy before closing up the tank. Any marine epoxy will do.

Laminating anything inside the "tank" space would be a terrible job, but I think you could get under your engine bed based on the photos with a roller/brush on a stick.

I have also had good luck with bladders. Seen some factories put in a sacrificial layer of PVC fabric that is held up with glue on tabs.

[SV__Grace]

We've replaced our engine, generator, and one fuel tank using several boatyards and vendors (in California), and they all referred to the fore-aft cross members used for mounting/securing them as "cleats."

All the old ones had to be cut away and replaced with new ones that fit the new installation, a minor part of the job- just glassing in some wood and painting it.

[Grey Goat]

Your installation 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 for cleaning.

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.

Good luck.

[56 South]

Have you considered cutting an inspection cover in the top of the fuel tank, in situ. You can then use a liquid tank sealer and repair the tank without destroying the engine bed and creating problems trying to realign the shaft.
In Australia an excellent fuel tank sealer is KBS Gold Standard tank sealer. I used this while restoring vintage cars whose tanks were irreplaceable and it was simple to use and highly effective. There is a kit offered which has a cleaner/degreaser and a paint preparation with the sealant. I found this excellent and offer the idea to you for your consideration. Best of luck.
Russ

[cadmus]

Originally Posted by 56 South

Have you considered cutting an inspection cover in the top of the fuel tank, in situ. You can then use a liquid tank sealer and repair the tank without destroying the engine bed and creating problems trying to realign the shaft.
In Australia an excellent fuel tank sealer is KBS Gold Standard tank sealer. I used this while restoring vintage cars whose tanks were irreplaceable and it was simple to use and highly effective. There is a kit offered which has a cleaner/degreaser and a paint preparation with the sealant. I found this excellent and offer the idea to you for your consideration. Best of luck.
Russ

Originally Posted by Pillroller

What about a flexible water tank, i.e. like a bladder? you can put it into the old tank and fit a F.G. or painted, epoxied wooden plate over the tank. Only need to take out the horizontal bit between the beds and replace with bearer across at the front/back, to retain rigidity. Good luck.

Thanks for this. Indeed coatings and the flexible bladders were considered. But it is beyond that level of corrosion. The boat is new to me and it was let go for too long. Something I will use in 20 years when the new one starts to fail.