Ing

I've noticed that on both the IO and OB models, the 24' Superboat has vent plates on each side of the cockpit near the area of the front seats. I can understand inlet venting for an IO engine but why would the OB deck have the same vents? Is it for rigging purposes to affix the coaming pads or standup bolsters? That's the only theory I can come up with because it has nothing to do with the sit down seating. What's the word on these vents? Thanks

FX10

Two purposes. First is Venting for the Closed compartment Gas tank. Coast Guard regulation. And it gives access to bolting the side combing and bolsters.

Ing

Well that explains that. Thanks Rick.

Ing

Not to belabor the issue but my understanding of the USCG regs are that since an outboard powered boat is not considered enclosed machinery, and all electrical ignition components are outside the hull on an outboard, the ventilation you mentioned is not requisite for the outboard powered 24. I've not seen any vents like this on any other manufacturers OB boats.

USCG Regs 33 CFR 183.620
§ 183.620 Natural ventilation system.

(a) Except for compartments open to the atmosphere, a natural ventilation system that meets the requirements of §183.630 must be provided for each compartment in a boat that:

(1) Contains a permanently installed gasoline engine; OUTBOARD IS NOT PERMANENTLY INSTALLED ENGINE

(2) Has openings between it and a compartment that requires ventilation, where the aggregate area of those openings exceeds 2 percent of the area between the compartments, except as provided in paragraph (c) of this section; NOT APPLICABLE TO THE 24 OB

(3) Contains a permanently installed fuel tank and an electrical component that is not ignition protected in accordance with §183.410(a); THE ELECTRICAL COMPONENTS ON AN OUTBOARD ARE IGNITION PROTECTED AS ARE TRIM TAB PUMPS.

(4) Contains a fuel tank that vents into that compartment; or NOT APPLICABLE TO THE 24 OB

(5) Contains a non-metallic fuel tank: NOT APPLICABLE TO THE 24 OB

USCG Regs 33 CFR 183.552
§ 183.552 Plastic encased fuel tanks: Installation.
top
(a) Each fuel tank encased in cellular plastic foam or in fiber reinforced plastic must have the connections, fittings, and labels accessible for inspection and maintenance.

(b) If a metallic fuel tank is encased in cellular plastic or in fiber reinforced plastic, water must not collect between the plastic and the surface of the tank or be held against the tank by capillary action.

(c) If the plastic is bonded to the surface of a metallic fuel tank, the adhesive strength of the metal to the plastic bond must exceed the cohesive strength of the plastic.

I BELIEVE THE USCG REGS BACK UP MY OPINION THAT THERE IS NO LEGAL REQUISITE FOR THE VENT ON THE OUTBOARD POWERED 24. THE IO 24 DOES REQUIRE THE VENTILATION.

I'M JUST BEING NIT PICKY BECAUSE I'VE ALWAYS THOUGHT THE LINES OF THE 24OB ARE SO CLASSIC LOOKING EXCEPT THE VENT WAS UNSIGHTLY AND SEEMS OUT OF PLACE.

FX10

Sec. 183.420 Batteries
There must be a means to vent hydrogen gas from the batteries to the atmosphere. Hydrogen gas is extremely flammable. The slightest spark will set off an explosion. Hydrogen gas discharged by a battery during charging must not be trapped in the boat, but free to make it's way out of the compartment to the atmosphere. Make sure the battery compartment is ventilated. If you put the battery in a box, make sure the box is vented and the gas has a way to escape from the compartment where the battery is located. Hydrogen dissipates very rapidly. A simple hole in the top of the compartment will work.
Ever open a hatch and smell gas fumes? I have many times. Better safe then sorry.

Ing

There is enough air circulating in the bilge area of an outboard powered boat to evacuate any fumes. Hydrogen is a lighter than O2 gas that easily disapates and hydrogen from batteries is not an issue or the USCG regs would clearly specify as a ventilation issue. There is no evidence of boats exploding from hydrogen released from batteries. Boats catch fire due to poor evacuation of gasoline fumes that settle at the lowest spot in the bildge. That's why a bildge blower and vents are required in an IO boat. That's also why opening an engine hatch prior to operating a bildge blower for several minutes before starting an IO boat is a bad idea. Opening the hatch prior to blower operation does nothing but move gas fumes around rather than allow the bildge blowers to work. If the deck vents are required for rigging purposes thats one thing but the USCG regs are clear that OB boats do not require venting. Call the local USCG Marine Inspectors, they will tell you the same. My sole reason with bringing this issue up is the 24 Superboat is an awesome vessel with great classic lines but those vents are unsightly and not required by law.

02cool

Rick, is correct about the vents for access to cockpit interior mounting bolt access & venting. The louvres in my opinion are a classic look. A very EASY and inexpensive thing ,is to replace the louvred vents w/ a flush mount vent that has the louvres recessed in the gunnells. From outside the boat everything looks streamline[ if that is your goal] you remove the[8] 8 x 3/4" pan head screws and replace the "Louvered Vents" with either fancy billet alum. ones from Rex or Dana Marine for about 100 bucks, or you go to West Marine and by the white plastic ones[ which I prefer] for about 35 bucks!

02cool

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FX10

Ing.
Without those vents. There is NO air circulation in the bilge area. And if so. Where is it coming from? If you close off those vents, where is the air circulation in the bilge coming from? I come on here being a nice guy and answering questions. And for that I get beat up online. If you know the answer, why are you asking the question?

Ing

The intent of my original question was to answer why the 24 OB is rigged with a deck vent plate that in my personal opinion detracts from the aesthetics of the boat. I did not know the answer why you guys rig this specific boat that way nor am I beating up on you.

This observation was made after viewing the SB 21 OB, SB 34 OB and similar OB powered boats made by Progression, Hustler, Checkmate, Activator, Kryptonite, Pantera, Talon, Velocity, Sutphen and Powerplay. None of these OB manufactures have deck plate vents and neither do other Superboats.

You made the statement that the plate was due to an USCG regulation, After giving your reply some thought, I recalled hearing during my USCG licensing process that most OB powered vessels were exempt ventilation. I then did some research and found that the USCG regs are pretty concise regarding space ventilation. My contention remains that ventilation of the bilge area space of an outboard powered boat is not legally required and I believe the USCG regs back up my opinion.

Bottom line, the SB 24 OB has the vent plate to assist in accessing the coaming area for rigging purposes. I understand that. OSO is an open forum and it’s quite possible a person with USCG Marine Inspections experience will clarify the regs and correct me. That’s perfectly OK too.

Rick, I sincerely apologize if the tone of my replies seemed like a personal attack on you. They were not in anyway intended to be construed that way. I had the pleasure of meeting you and John a few years back at the shop. You guys were perfect gentleman and spent some time answering my questions about the boats you guys build. I have always been in awe of your personal skill, craftsmanship and dedication to building one awesome boat and look forward to reading and seeing more of your builds.