Drilling through wood panels

[paulga]

i was thinking something like this:
View attachment 145606

is this sleeve good for exhaust pipe insulation?

 

[Bmarler]

Thanks for the drawing!

what does the stand off pieces look like? it seems they are spacers between the shield and the wood panel on the back

on the sketch i put broken sides for stand off. you can use plain flat sheet instead and use just about anything for spacers to stand it off from the wood panel. maybe little blocks or rounds of aluminum or hard ceramic stand off spacers.
here's some aluminum ones: https://www.amazon.com/Aluminum-Len...27027&s=industrial&sr=1-4&ts_id=16413321&th=1

 

[Bmarler]

there's a few options for exhaust sleeve.
here's a silicone option: https://www.lubricationspecialist.com/exhaust-components/silicon-fire-sleeve/

or this fiber one: https://www.heatso.com/exhaust-hose-lagging-insulation-1-meter/

 

[paulga]

on the sketch i put broken sides for stand off. you can use plain flat sheet instead and use just about anything for spacers to stand it off from the wood panel. maybe little blocks or rounds of aluminum or hard ceramic stand off spacers.
here's some aluminum ones: https://www.amazon.com/Aluminum-Len...27027&s=industrial&sr=1-4&ts_id=16413321&th=1

so the offset sides work as stand off pieces.
is a 0.8mm (22 gauge) sheet thick enough for a shield?

 

[Bmarler]

so the offset sides work as stand off pieces.
is a 0.8mm (22 gauge) sheet thick enough for a shield?

yes, that should be plenty thick to do the job.

 

[paulga]

there's a few options for exhaust sleeve.
here's a silicone option: Silicon Fire Sleeve: Espar Heater Parts, Diesel Truck Heaters - Lubrication Specialist

or this fiber one: Exhaust hose lagging (insulation) 1 meter

@Bmarler is the lagging wrapped on top of the sleeve? or directly around the exhaust pipe without a sleeve?

silicone sleeves seem to have an operating temp up to 500F (one example, also this one), but the exhaust temp can get higher than that (500-600F) : see Forced Air Diesel Heater Exhaust Pipe

why is this PAN sleeve that has a much higher temp rating not a good choice?

 

[paulga]

continuing the project to keep posts under the same thread

with the removable back panel out of the way, i got a clear view of the stuff behind the panel. the cables shown are electrical wires running b/t the aft and forward. The slightly brighter area is the engine room vent. so I guess the contour shape on the hull is the "air duct" of the bilge.

the most promising location of the through hull based on my gut feeling is where I have marked a circle. this area is 3" wide, with a 1.75" hole, there will only be 5/8" clearance on each side of the hole, is this too narrow?

 

[Bmarler]

I’m thinking that’s enough room. You’ll have the whole thing covered in lagging to protect the surrounding area anyway.
I would, however, bundle and secure the cables so they are routed away from the exhaust as much as possible.

 

[paulga]

I’m thinking that’s enough room. You’ll have the whole thing covered in lagging to protect the surrounding area anyway.
I would, however, bundle and secure the cables so they are routed away from the exhaust as much as possible.

yes, I also planned to shield the wires with thermal wrap and stainless zip tie

why does the fiberglass hull have a tiered structure - 3 "steps" shown in the photos?

Also, the thickness is not uniform across the fiberglass - the top area as I marked in green seems to be thinner than the selected location, as it appears brighter.

 

[paulga]

I had planned to send the hot air through the separation wall b/t the aft cabin and the salon closet (drilling a 79mm hole). now i just noticed the wall is more than one plywood panel.

behind the 1/4" plywood panel (closet wall), there is a 5/8" wood plate. one side of the plate looks to have been brushed with epoxy and fused with the hull fiberglass wall. the other side has a thick layer of white stuff. Photo 2 - 4 are taken with an endo camera around the edge of the plate. Then there should be another layer of 1/4" plywood after the white stuff.

is this wall important in the boat integrity?

 

[RT Firefly]

Greetings,
Ms. p. I think I'm pretty safe in saying that if that bulkhead (wall) is bonded to the hull it does play some part in structural integrity. Not too many boat builders I'm familiar with add "extra" stuff. The bottom line for builders, particularly Asian builders is calculated to the penny.

 

[paulga]

Greetings,
Ms. p. I think I'm pretty safe in saying that if that bulkhead (wall) is bonded to the hull it does play some part in structural integrity. Not too many boat builders I'm familiar with add "extra" stuff. The bottom line for builders, particularly Asian builders is calculated to the penny.

Is it ok to drill a hole on this wall?
The muffler exhaust in the bilge is also through the same wall
If the hole size matters, i can use a reducer to change to 60mm

 

[Bmarler]

It’s ok to drill through that wall, but try to stay in the middle, so that there is solid plywood all around the hole.
The three tier section is likely where two different mold forms come together, or a structural backing for rub rails, or similar. I’d have to look at the construction inside and out to be sure.

 

[Cigatoo]

The test hole needs to be about 3/8" for inspection

If it's necessary to drill another hole, is it easy to patch the test hole using a plug and glue?

Drill exactly 3/8 and plug with a 3/8 bung plug. Be sure to line up the wood grains.

 

[paulga]

Drill exactly 3/8 and plug with a 3/8 bung plug. Be sure to line up the wood grains.

Using an endo cam is awkward. It has multiway actuator, still very easy to throw the observer into confusion. Now that the back panel can be removed, I have a direct view of the hull and the wiring

 

[paulga]

It’s ok to drill through that wall, but try to stay in the middle, so that there is solid plywood all around the hole.
The three tier section is likely where two different mold forms come together, or a structural backing for rub rails, or similar. I’d have to look at the construction inside and out to be sure.

Another question is if there are other structures under the surface of the exhaust through hull location (orange marker in post #39). How to see it through before drilling.

The magnet shows the corresponding location on the outside. The inside magnet should be a bit higher, given the magnetic force felt medium.

The survey report says the hull exterior is solid fiberglass. Since the inside magnet can hold the other one, the hull thickness feels like a 5/8" lumber.

 

[CharlieO.]

Is that where you're looking for your heater exhaust?

 

[paulga]

Is that where you're looking for your heater exhaust?

Yes. It was determined from the inside. It's not desirable as it is close to the vent but I didn't see an alternative spot, see post #39

 

[CharlieO.]

I agree, I don't think I'd be comfortable with the exhaust that close to the vent.

 

[paulga]

I agree, I don't think I'd be comfortable with the exhaust that close to the vent.

That vent will remain sealed when the heater is needed

 

[Bmarler]

Impossible for me to tell from here if there’s anything in the path of the drill. From the pictures though, it seems like just solid glass.
I didn’t know about the engine room vent before, now you know why you have that tiered structure above the heater outlet. Take care not to breach that as you’re installing things.

 

[paulga]

Impossible for me to tell from here if there’s anything in the path of the drill. From the pictures though, it seems like just solid glass.
I didn’t know about the engine room vent before, now you know why you have that tiered structure above the heater outlet. Take care not to breach that as you’re installing things.

I supposed those ridges are "air duct" system of the bilge, the "air duct" connects to the outside vent. Please see my post #37. what I didn't understand is why they need to build 3 layers, so the ridges shows a 3 "step" shape. it maybe a technique in hull building to stack fiberglass layers of smaller depth to conserve space, or they didn't have a deep mould

 

[paulga]

I agree, I don't think I'd be comfortable with the exhaust that close to the vent.

The guideline seems to be 10ft b/t an exhaust and an air intake. The distance b/t the two vents is only half of that. There is not a spot on the topside that fulfills the 10ft clearance unless it's installed in the aft cabin, which is not ideal either.

 

[paulga]

It’s ok to drill through that wall, but try to stay in the middle, so that there is solid plywood all around the hole.
The three tier section is likely where two different mold forms come together, or a structural backing for rub rails, or similar. I’d have to look at the construction inside and out to be sure.

I just noticed this bulkhead wall is bearing the load of the port side deck.

to create a penetration on this wall, is there difference b/t a 60mm and a 75mm hole?

the outer layer of the wall is painted white (refer to the last two photos in post #40), what is the purpose of the white stuff?

 

[Bmarler]

I supposed those ridges are "air duct" system of the bilge, the "air duct" connects to the outside vent. Please see my post #37. what I didn't understand is why they need to build 3 layers, so the ridges shows a 3 "step" shape. it maybe a technique in hull building to stack fiberglass layers of smaller depth to conserve space, or they didn't have a deep mould

Who knows why there’s three ridges? Could be many reasons. Could be duct for different areas, conduit for wire or plumbing, etc…

 

[Bmarler]

I just noticed this bulkhead wall is bearing the load of the port side deck.

to create a penetration on this wall, is there difference b/t a 60mm and a 75mm hole?

the outer layer of the wall is painted white (refer to the last two photos in post #40), what is the purpose of the white stuff?

View attachment 155895

If you’re worried about the hole size weakening the structure, you can size the hole to snugly fit a piece of pipe and glass or glue it in place. Personally, I wouldn’t sweat it. Plywood panels are pretty tolerant of holes mid-panel.
The white stuff? No idea. But coatings are for appearance or protection. It’s not very pretty, so I can only surmise it’s a protection coat for some reason.
Heck, it could even be a leftover piece of lumber used to build a mold or something.
The yards where these were built weren’t fancy clean factories, they were rickety sheds full of all manner of things.

 

[paulga]

Who knows why there’s three ridges? Could be many reasons. Could be duct for different areas, conduit for wire or plumbing, etc…

I thought it's a common design also seen in other boats

 

[paulga]

If you’re worried about the hole size weakening the structure, you can size the hole to snugly fit a piece of pipe and glass or glue it in place. Personally, I wouldn’t sweat it. Plywood panels are pretty tolerant of holes mid-panel.
The white stuff? No idea. But coatings are for appearance or protection. It’s not very pretty, so I can only surmise it’s a protection coat for some reason.
Heck, it could even be a leftover piece of lumber used to build a mold or something.
The yards where these were built weren’t fancy clean factories, they were rickety sheds full of all manner of things.

@Bmarler If I put this duct joiner through the wall -

does it need any kind of insulation around it?

Do you need to take its heat expansion into account when deciding the hole size?

 

[Bmarler]

I’ve not insulated those connectors, just slide the duct hose on as far as possible and clamp. No need to allow for expansion, I like to fit the connector snug to the hole so it doesn’t move or rattle when the engine is running.

 

[paulga]

I’ve not insulated those connectors, just slide the duct hose on as far as possible and clamp. No need to allow for expansion, I like to fit the connector snug to the hole so it doesn’t move or rattle when the engine is running.

My point was to separate the hot air passage from the wood.

If I pass the air duct as shown below, through the hole, without using a duct joiner, does it require insulation at the contact with wood, e.g. using 1/16" ceramic fiber?