Side induction air boxes.....

IRGuy · Post by **IRGuy** » Sep 6th, '10, 09:34

Capt Pat.. et al.....

I am considering fabricating and installing a set of custom side induction air boxes on "Phoenix", and removing the four deck mounted engine air scoops the B33s came with.

As part of my early design phase I have been wandering around local marinas looking at boats that have them, taking measurements, peering inside them to see how the baffles are arranged, etc.

One thing you did not mention in your article in the Tips section is screening to keep bugs out. Here in NC we have yearly battles with mud wasps, which build nests in sheltered places such as vents and other protected areas, out of mud that remains for years if not physically broken up and/or washed away. This past weekend I saw the largest nest ever.. it was the size of a small grapefruit, hidden from normal view on the underside of a sloping panel, which I assume was an air deflector.

For more than 20 years I have secretly held onto several square feet of stainless steel window screen, knowing that one day it would come in handy on a boat. It would certainly make a great screen to be used in the air induction boxes I am considering, but I am concerned that it might add a restriction to the air flow, which with my present design, fits between two engine room bulkheads spaced 36" apart. It has in general the same wire size and spacing as regular aluminum screen I can buy at my local hardware store. I can get about 160 sq in of unrestricted free area for each 315 HP Cummins 6B engine with my present design, without the screen. I know you suggest one half square inch of free area per engine HP, and I might be overanalyzing the screen's effect on air flow. (Not an uncommon thing for me, I admit!).

I would appreciate hearing any comments you and any others might want to make in this regard.

Thanks..

CaptPatrick · Post by **CaptPatrick** » Sep 6th, '10, 09:57

Frank,

The screen would pose no appreciable air restriction problems. Remember that "optimal free air delivery" is a shooting mark and as long as you try to design for that volume, you're fine even if you under shoot it by by 10% or so.

Also, Cypermethrin, is a very good deterant to mud daubers and other wasps... Spray all areas that might be, or have been, problem spots with it every spring and as needed through the summer. More discussion at the link above...

Raybo Marine NY · Post by **Raybo Marine NY** » Sep 6th, '10, 10:02

on the topic- for others looking for all kinds of screen I have ordered from this company a few times

http://www.twpinc.com/twp/jsp/product.jsp?type=12

CaptPatrick · Post by **CaptPatrick** » Sep 6th, '10, 11:08

After re-reading my own post, I'm recanting my statement of "screen would pose no appreciable air restriction problems"...

A screen with mesh small enough, with wire size large enough to be practical, to exclude a small wasp style critter would have a pretty large impact on your free air delivery. You'd have to alter your design to allow for at least 60% open area, meaning that to have "optimal air", your design would have to be 40% larger if an 8 Mesh .028" Wire Dia. were used. The finer mesh "window screen" you have, would depend on the wire size used as to the percentage of open area it has.

I've also purchased from TWP before and looking over their offerings, the 16 Mesh T304 Stainless .009" Wire Dia., which is 73% opening would still require a 27% increase in air box size.

So optimal size for the 315 BTAs, using the 16 mesh x .009 wire, would be 216 sq in of free flow. Reducing that by 10% would still be 195 sq in.

I'm now thinking that spraying with Cypermethrin and routine visual checks for nests, forgetting the wire mesh, would be the best way to go. Even a a couple of good sized daubber nests would result in less air restriction than the screen...

Brewster Minton · Post by **Brewster Minton** » Sep 6th, '10, 11:35

How about a screen that is placed there when boat is not being used. When you use boat just pull screen out and go.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 6th, '10, 20:01

I'm using that insecticide and it works real good on dirt daubers and spiders & ants too. Only downside is they concentrate in spots you miss with the spray and gang up to make mega dirt dauber houses....I had one on the front of my overhead electronics box the size of a damn tennis shoe. I'll re-spray again this week...if they fly, they die....I use bronze window screen left over from my SSB ground project a few years ago to block the little critters in outboard motors and battery boxes. And by the way, the suggestion that moth balls deter them is b.s......I put a cup frull of moth balls under the Stamoid cover over my instrument panel and the little bastards built a fine home on the side of the damn cup.

UV

IRGuy · Post by **IRGuy** » Sep 7th, '10, 20:19

Thanks guys...

Capt Pat...
Thanks for the info on the bugacide, I think I will give it a try. And thanks for the follow up with the additional info..

Rybo...
Thanks for the TWP link.. I have been looking for a site like this for a while.

Brewster...
I agree a temporary screen might work, and have been trying to work this into my design, but I think I will follow UV's lead and spray the repellant on the surfaces in question and see what the daubers do for a year or so. They already seem to have lots of access to my boat, as I find their old nests in surprising places.. they seem to last forever unless you physically destroy them, and I suspect some of the empty nests I have found are several years old.

UV... With so many things on my plate now (I am removing all the paint the previous owner rolled on several years ago on the deck, cabin sides, and the flybridge, in preparation for an AwlCraft 2000 paint job) and time is at a premium, I think I will design the possibility of temporary screens into the package but hold off on making them until a year or so and see how the repellant works.

This string is just another example of how valuable this site is for guys like me working pretty much on their own!

Raybo Marine NY · Post by **Raybo Marine NY** » Sep 8th, '10, 07:38

if its temporary screen why not consider a sunbrella cover of some sort, that will really keep them out

IRGuy · Post by **IRGuy** » Sep 8th, '10, 08:06

Damn.. Just when I think I am settled on the right track someone comes up with another good idea!

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 8th, '10, 08:56

Warning on canvas covers.....the daubers will find a way under them no matter how firmly you attach them, and love the warm, dark places the covers provide. I have abandoned virtually all covers around the camp, such as for the bbq pit, lawn furniture, etc. as the daubers find them a good home. The inst. panel cover on AJ is there to keep the sun off the plastic Cummins panels only.

The stuff I'm using is branded Cyn-Off and comes from domyownpestcontrol.com - its about $52 a pound, a fine powder you mix with water and spray. A little goes a long way.

The daubers re-use the mud nests so after you kill them its a good idea to remove the nest. A large hammer makes a satisfying weapon for that, altho it does make a mess.

UV

Rawleigh · Post by **Rawleigh** » Sep 8th, '10, 09:04

How about imbedding a steel rim that is completely encase in the epoxy around the vent so that the cover can have some of the really strong rare earth magnets sewn into the border. That way it would stick firmly to the boat hull and exclude all critters.

CaptPatrick · Post by **CaptPatrick** » Sep 8th, '10, 09:19

Damn Rawleigh, that sounds like one of my wheel re-inventions...

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 8th, '10, 09:41

Or get some Chinese children with fly swatters to stand by the vents?? Sorta like the ones that live in the frig to turn the light on?

Must be a slow day in White Stone, Va, huh Swimps Pimp?

UV

AndreF · Post by **AndreF** » Sep 8th, '10, 09:44

I just use rags stuffed into all the openings/thru hulls and pray I remember all when firing up.
I can send pictures if you like.

Raybo Marine NY · Post by **Raybo Marine NY** » Sep 8th, '10, 10:06

sneaky little bastards huh?

IRGuy · Post by **IRGuy** » Sep 8th, '10, 10:30

In one of my early careers I was an independant contractor building and repairing railroad side track. I used to hire a guy with a D9 cat dozer to do excavating. One day he was showing me how to run the thing. I noticed he had a bath towel near the seat, and asked him why.

His answer.. on a steep incline the engine oil could wind up getting past the piston rings be burned as fuel, and causing the engine to runaway. He stuffed the towel into the air intake to stop it.

Andre.. Be sure to remove all those rags!

Cunado · Post by **Cunado** » Sep 17th, '10, 15:06

Using cypermethrin is good advice. If you have any friends that farm ask them for a few ounces of "Mustang Max"(which will last you a long time) it's the agricultural label for zeta-cypermethrin. I'm surprised no one has relabeled the ag version as "Boating and Marine Wasp-be -Gone" adulterated it and charged 400% more for it.

IRGuy · Post by **IRGuy** » Sep 18th, '10, 01:11

Cunado...

I don't know any farmers personally, but there are a couple of farm supply stores here.. I will look there first.

Thanks!

Cunado · Post by **Cunado** » Sep 19th, '10, 10:18

IR Guy,

The mustang max is a highly concentrated liquid sold in 1 gallon jugs. Since you don't know anyone who can just give you a few ounces, I Ithink your best route is defenitely UV's suggested web site or similar with the one lb. powder. It's something you can use around the house, garden etc. and kills about everything except aphids and whiteflies. I purchased my boat from South Carolina and some of those buggers came with it. I think they are craftier than the ones down here in Texas. We found them all over the place. Good luck!

bertram31.com

Side induction air boxes.....

Side induction air boxes.....

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