How to remove exhaust water lifter

[Balmbra]

Been reading this forum for over 30 years so I know someone will have a good suggestion.
Northern 29 sailboat with Universal m3-20 diesel which replaced original Atomic 4. The stainless steel lifter was not relocated by PO and needs to be fixed aft of engine. (The Atomic 4 manifold exit was forward). The lifter is epoxied to a hull shaped 1/2" exterior grade plywood pad, which is also epoxied to the interior of the fibre glass hull. The 3/4" thick hull, was very well constructed and in excellent condition. Pad looks good. Any ideas how to remove plywood and/or lifter from hull without damaging lifter? The motor is midships, under cabin seat, so has phenomenal access. I am pondering a wide chisel and not happy about it. Those of you who know the Northerns built in Ajax, Ontario and the builder's reputation will know Dennis quality work.

[Wotname]

Welcome aboard CF, nice to see a reader become a poster

There might be better ideas and not knowing how big the lifter is but I might consider using heat. Epoxy softens as it gets hot and maybe judicious use of a hot air gun on the SS lifter might allow it's removal. However I haven't tried this in the situation you describe!

[Balmbra]

Thank you. Never thought of heat - the cold weather is coming so I had better hurry. Other ideas are still welcome.

[model 10]

Rip the plywood apart with a flat bar and a big hammer.

[Squanderbucks]

Forget the hammer for any big pieces or heavy blows. Might use it to help in removal of the plywood once it is scored all the way through along with a nice chisel - but not into the underlying FRP.
First tool to have is something like a Fein ocellating saw. You can rotate the various blades to several angles and make precise depth cuts in the plywood. It will make quick work of this project. Once you have one of these you will wonder how you ever worked on a boat without one. When you are down to the last pieces you can use the blade to get under the last section and cut horizontally and pry it off.
It also has sander attachments and can get into places like this pretty well for the clean up.

It is one of the two specialty tools that I find I must have and go to all the time - the other is a Dewalt 90 degree 3/8 inch 18 volt drill. Installs and removes screws in places no other standard drill can think of.

[nitpik]

If the heat gun does not work, I would be inclined to sacrifice the plywood to save the lifter. Sawzall might be a little gentler than big hammer! Just cut it out, then it will be easier to remove the lifter from the remains of the plywood shelf when you have the assembly out of the boat, and on the work bench.

[jharding]

I second the fein multi tool, could not live with out it, cut into the middle of the plywood layers all around then split it open with chisel or bar.

[roverhi]

What's a 'lifter'??

[hellosailor]

Wotname, I've seen epoxy refuse to wake up after an hour in a 450F oven. Literally.

I'd also vote for the fein tool (oscillating saw) but that will probably have a limit of 1-2" of cutting depth. It WILL get the plywood plys starting to separate though. Then using a SawZall, if it can fit in there, or else a wide sharp chisel and some judicious tapping should split the plywood apart. I'd try to split it closer to the water lift, keeping clear of the hull, and then use an angle grinder afterwards to chew the rest of the plywood clear.

Reinstall with nuts & bolts, since even stainless water lifts have been known to need replacement every couple of decades!

[Toccata]

Fein multitool with the large (2/3 of a circle) blade
Hold it on the existing hull surface and work all around the edge of the ply
Marvellous tool.
Have a look at a vetus waterlock as the replacement, plastic (wont corrode) and the barrel shape version, has many inlet/outlet position alternatives.

[Wotname]

Originally Posted by roverhi

What's a 'lifter'??

Another name for a exhaust waterlock etc.

[Wotname]

Originally Posted by hellosailor

Wotname, I've seen epoxy refuse to wake up after an hour in a 450F oven. Literally.

.............!

This may well be true yet many epoxies do soften at much lower temperatures and as the OP has a SS water lifter (waterlock), a goodly (but not excessive) amount of heat can be applied with some expectation the lifter won't be damaged.

Resolves difficult access problems needed for sawing or whacking!

However the OP will have to determine for himself whether it will work in his situation or not. As stated earlier, I have not tried to myself to remove a glued down SS water lift using this method but I have had good success in using heat to soften epoxy glues in other industrial situations.

[Capt Ben]

Originally Posted by Balmbra

Thank you. Never thought of heat - the cold weather is coming so I had better hurry. Other ideas are still welcome.

Actually, the cold weather may help you as it keeps the underlying hull roving and glass cool.

[a64pilot]

Couldn’t a multi-tool get in between the muffler and the wood?
Seeing as how the muffler is steel, I think I’d ever try a torch to see if that would soften the adhesive enough

[HoneyRyder]

If it was me and the access was good then I'd use an angle grinder. I have worn out half a dozen of them over the years cutting stuff out of my boat, goes through anything. Just be careful to keep your cuts straight and resist the temptation to work the tool or else it can catch in which case it becomes a dangerous weapon.