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**Guest** · 02-14-2012, 01:02 AM

I wonder about the use of aluminum in this environment. The expanded metal part in particular seems like it might be prone to corrosion. Salt spray on the black mesh? I am not sure if you can get expanded metal in the right grade of aluminum for this use either. There is a stainless steel screen material that is round stock woven over and under like screen. You can get this in mesh in sizes right down to 1/8 inch and bigger from there. It has quite a bit of structural integrity, quite a bit more than expanded metal and less Likely to rattle. Good looking stuff I like the idea of building something custom for the vents. One other design I see over and over in engine vents is that they are usually not open. I think the idea is to have a large opening around a cover that stands off, allowing flow around and under it. There is an internal sill that stands behind the outer cover that deflects water to flow off, and not in the boat. Should not a good vent allow you to throw a bucket of water at it, and have much of it not come in the vent? A venetian blind kind of look,....partly open,.... would look good and deflect water out. Mesh behind that?

Just some thoughts..... good luck. Steve

**mmichellich** · 02-14-2012, 06:16 AM

Would recommend stainless or some form of plastic. Aluminum will look bad in a year or so.

**Guest** · 02-14-2012, 06:34 AM

3 comments:

The design you've worked up looks really good, especially with black mesh.
I agree with the concerns about aluminium. Is there a reason you're suggesting aluminium and not SS?
I would take this opportunity to build dorades inside the engine room to catch and divert all water that comes in the vents.

**Guest** · 02-14-2012, 07:19 AM

You could always powder coat the aluminum .

**kwb** · 02-14-2012, 12:18 PM

Aluminum choice was because it is easier to work with and with proper application of paint I am not worried about it. Stainless would be nice and could look really trick if I wanted to go to efforts of metal finishing and polishing. I also considered polished aluminum with clear to get a bright streak through this but have enough dealing with cleared aluminum at work that a "real" paint over proper primer is a much better way to go. If I have to repaint it in a few yrs it isn't a big deal to do, Powder will suffer same fate as paint and somewhere it will get a bubble going it might take a year or two longer but at the added cost to go with powder for the little better life it doesn't pencil for how I value my time.

I have played with designs that could shed water better but just havent come up with anything that would be fairly simple to build and still remain low profile enough to not take too much abuse from fenders. My thinking is the Ribs are close enough and tall enough that the screen (woven wire mesh) won't get too much pressure from fenders and end up looking too ratty too soon. I also figured if the original design didn't shed water then it wasn't too important to go that route when I come up with something.

I have yet to see a plastic replacement that didn't look like a cutting board with drains screwed to the side of a boat. If you want a plastic one you need tooling to mold something otherwise the trimmed edges look like poo where the texture is lost. I have seen some done with waterjet metal and layers of material that look good but to get there I would have more money in this than I want to have.

**Johnny_Vintage** · 02-14-2012, 03:46 PM

I wouldn't consider aluminium. It will look like crap real fast. Yes, you could pull them off every year and re-paint them but that would be a giant pain in the rectum. Getting the paint off, sanding down all the salt water pitting....we've got enough to do already with these dang boats.

Looking at your drawing, you obviously are using some type of modeling software. I'm sure you've seen all of the grill inserts that guys in their pick up trucks are installing. You know like the flames etc.

Have you ever notice how little those cost?

If you draw something in the foot print of your vent size, and make sure the square inches of opening are the same or more as your original vents, you can do any design you want at all. Convert the drawing to a DXF file and send it to a Laser Cutting shop and have it cut out using 12 ga. type 36 stainless steel. You can use a 180 grit like I did, bright anneal or have the pieces electro polished. Plush it's really cheap to have them made. Stainless is actually not that expensive. 12 ga. is about 10 bucks a square foot

They look awesome and you'll never have to touch them again.

I did mine to match my logo. The only difference is that I made mine out of 16 ga. and had the edges bent back 1/2" on the four sides. I put weep holes along the bottom edge to get rid of any water.

**kwb** · 02-14-2012, 05:21 PM

Apparently you guys haven't seen a good paint job on aluminum or if you have you didn't notice it because it wasn't bubbling. It is done and I have had decent results with things I have done for the boat in the past. No you aren't using a bomb can - you have to buy a good catalyzed polyurethane paint and good primers designed for the task at hand. I am figuring ~5yrs before I have anything that I think will need to be redone. There will be as much or more paint prep time in these as the actual fabrication.

Problem with flat sheet stainless (which is what the PO did minus getting any good open area) is that it has no depth or shadow lines to it and to get depth is a lot more work (read costs) from sheetmetal supplier. When a brushed finish is used it will get contamination trapped in the small scratches and get discolored (it is after all called StainLESS) If you want it to stay bright it needs to be a highly polished finish. Flat sheet also has no stiffness so gaps to the hull are often inconsistent and pillows between fasteners and will rattle like a mo-fo.

**Guest** · 02-14-2012, 06:11 PM

What I didn't like about the original vents is that all there was between a big hole in the side of your boat was a decorative louver!I installed a proper louver to stop rain, hose washdown (and maybe a large wave) from flooding into the engine well and add a decorative louver over top.One mistake I made and will have to correct is that I used white sealer on the SS louver set and I should have used black.

[img]/media/kunena/attachments/vb/655898=24827-Portvent3.JPG[/img]

[img]/media/kunena/attachments/vb/655898=24828-Portvent.JPG[/img]

**kwb** · 02-14-2012, 06:20 PM

I will have to look closer next time I am at the boat but I could have sworn there was a box that made air go up and over and wasn't just a poorly cut hole in the side of the hull.

I do know I haven't seen much to indicate that water in the bilge was coming from the vents.

**SomeSailor** · 02-14-2012, 06:48 PM

If you're interested and have some CAD skills, I could cut them for ya on my router from some Starboard. Shoot me an email if you're interested. I don't need anything fancy, just .DXF files. The CNC loves the plastic and walks through it like butter.

**Johnny_Vintage** · 02-15-2012, 10:10 AM

I have a small bit of experience with metals as I have been in metal fabrication for over 40 years and at this point am employed by one of the largest metal manufacturer of the West Coast. We are mainly a stainless steel shop but also work in all other metals.I still say aluminium is a bad choice for the marine environment and here are a few reasons.Have a look at any crane on on the 45's and 47's. Peeling and pitted.Have a look at most radar mounts. Peeling and pitted.Have a look at your Muir windless. Peeling and pitting.And worse thing of all are the horrible aluminium window frames Bayliners have.Peeling, pitted and ugly.You also haven't mentioned how you are attaching the screen to the frame and the half rounds to the rectangles. Are you tack welding these together. Aluminium requires very high heat to weld and that screen will blow apart a soon as it's touch with a TIG torch.Grained stainless is fine in salt water especially if you use type 316. Your railings are 316 Ornamental stainless. Most of our marine BBQ's are 304 stainless with a 180 grit finish. This is actually a better choice as you can use a Scotch Brite pad to keep them clean. Touch the high polished finished one with a Scotch Brite pad and they are now grained. They look pretty though.One stainless to avoid is type 430 as it is magnetic and will rust like crazy. It's mainly used on stainless refrigerators around the perimeter where the magnetic door gasket touches so it pulls the door closed.If you are worried about flat stainless rattling like a Mo-Fo, here are a few suggestions to stop this and the pillowing effect you speak of. If you use a heavy enough gauge, 14 or heavier, you will not get any pillowing. If you use a lighter gauge, say 16, just have the shop put a 10 degree 1/2" wide kink around the edges.The other option is the MO-FO anti-rattling sticky one side gasket. A strip of 1/8" x 1/2" around the perimeter will de-MO-FO those quite nicely.Here's a pic of my old beast. I designed my graphics and Some Sailer did a great job of my logo decals. The one one my transome is about 48" long.If you look at my stainless steel vents, they are the same design as my logo decal. I just used basically the same file I sent Some Sailer but sent it to our laser machine. The boys in the back burnt them out. I then had the fellow on the brake turn the edges down 1/2". I welded and polished the corners myself at home with my little TIG set up. Took about an hour to do that.These are made from 16 gauge Type 304 stainless with a 180 grit (or grained if you like ) finish. I've had them on for 4 years now and other than washing them when I wash the boat, no other maintenance is required.Hope this helps you with a bit with your design decisions.

[img]/media/kunena/attachments/vb/656034=24836-Vents 3.jpg[/img]

**Guest** · 02-16-2012, 05:41 PM

kwb wrote:
I will have to look closer next time I am at the boat but I could have sworn there was a box that made air go up and over and wasn't just a poorly cut hole in the side of the hull.

I do know I haven't seen much to indicate that water in the bilge was coming from the vents.

The '38 has a box to divert water from entering into the boat. I know, I stuff it with rags in the wintertime.

**Guest** · 02-16-2012, 05:45 PM

Those are darn nice! Would I love some of those with Navy flight wings as the grillwork.!!! I'm waving a wad of money here...

Johnny Vintage wrote:
I have a small bit of experience with metals as I have been in metal fabrication for over 40 years and at this point am employed by one of the largest metal manufacturer of the West Coast. We are mainly a stainless steel shop but also work in all other metals.I still say aluminium is a bad choice for the marine environment and here are a few reasons.Have a look at any crane on on the 45's and 47's. Peeling and pitted.Have a look at most radar mounts. Peeling and pitted.Have a look at your Muir windless. Peeling and pitting.And worse thing of all are the horrible aluminium window frames Bayliners have.Peeling, pitted and ugly.You also haven't mentioned how you are attaching the screen to the frame and the half rounds to the rectangles. Are you tack welding these together. Aluminium requires very high heat to weld and that screen will blow apart a soon as it's touch with a TIG torch.Grained stainless is fine in salt water especially if you use type 316. Your railings are 316 Ornamental stainless. Most of our marine BBQ's are 304 stainless with a 180 grit finish. This is actually a better choice as you can use a Scotch Brite pad to keep them clean. Touch the high polished finished one with a Scotch Brite pad and they are now grained. They look pretty though.One stainless to avoid is type 430 as it is magnetic and will rust like crazy. It's mainly used on stainless refrigerators around the perimeter where the magnetic door gasket touches so it pulls the door closed.If you are worried about flat stainless rattling like a Mo-Fo, here are a few suggestions to stop this and the pillowing effect you speak of. If you use a heavy enough gauge, 14 or heavier, you will not get any pillowing. If you use a lighter gauge, say 16, just have the shop put a 10 degree 1/2" wide kink around the edges.The other option is the MO-FO anti-rattling sticky one side gasket. A strip of 1/8" x 1/2" around the perimeter will de-MO-FO those quite nicely.Here's a pic of my old beast. I designed my graphics and Some Sailer did a great job of my logo decals. The one one my transome is about 48" long.If you look at my stainless steel vents, they are the same design as my logo decal. I just used basically the same file I sent Some Sailer but sent it to our laser machine. The boys in the back burnt them out. I then had the fellow on the brake turn the edges down 1/2". I welded and polished the corners myself at home with my little TIG set up. Took about an hour to do that.These are made from 16 gauge Type 304 stainless with a 180 grit (or grained if you like ) finish. I've had them on for 4 years now and other than washing them when I wash the boat, no other maintenance is required.Hope this helps you with a bit with your design decisions.

http://baylinerownersclub.org/media/...ts 3.jpg[/img]

**Guest** · 02-16-2012, 07:20 PM

Aluminum can be treated and protected against salt water if treated properly. The reason you see the cranes peeling, is that the proper powder coating techniques did not exist until the last couple of years with the use of Fluorinated Powder coat and a good marine primer. Most powder coating shops have this technology and it's fairly inexpensive for what it is. As for Aluminum being a bad, using the proper grades of Aluminum is the key to the resistance of salt water corrosion. 5086 & 5083 are two marine grade alloys that work good around salt water. There are many Aluminum hulled boats running around the Puget Sound that look pretty darn good to me. If you are in the Everett area - the guys at Everett Steel can get you any grade you need. BTW - if you do use stainless...make sure you get the proper grades as well, or they will rust (even though it's called stainless). 316 is always a good choice for marine environments.http://www.crosslinkpowder.com/marin...ercoating.htmlOr you can make some bitchin' vents like it did!

[img]/media/kunena/attachments/vb/656438=24878-Sea-King.jpg[/img]

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