Hull Ventilation

[radioshop]

First, allow me to apologize for not having a SeaCraft. My boat isn't from Princeton, it's from Hialeah. It's none other than 73 22.2 Aquasport. I have been lurking here for a while. I'm impressed and amazed at your boats. I also learn something every time I'm here. We don't have a Classic Aquasport site yet, so please pardon me for imposing a non-brand specific technical question here.

I notice on many of your projects, you plug the aft freeboard vent. I assume Mr. Potter put that in for fuel tank ventilation. Is this a correct assumption? I also noted that plugging done mainly to keep water out of the boat. If my first assumption is correct, is the lack of ventilation an issue? Have you done anything to provide more if it is?

I have a similar vent on my Aquasport and, am considering plugging it when I redo the hull this winter. The only caveat is that I have a "sealed" bilge. Which means it's ventilated, but there's no bilge pump. The entire underdeck area is filled with foam. I'm thinking about re-vamping the ventilation system.

Thanks for your patience and, any advice in advance. I really do admire the SeaCraft's from the Potter era. Someday maybe I can even afford one. You're all doing a great job preserving the classics. Keep up the good work.
Regards,
Jason Swift

[ScottM]

radioshop,
Welcome to the site, and don't feel bad for being an "infidel", technically I'm one too (23' Seabird CC, although my father has a 23' SC Sceptre, so I have been accepted into the flock [img]/images/graemlins/wink.gif[/img]). Someday you will "see the light". [img]/images/graemlins/grin.gif[/img] Seriously though, there are other members who own different brands, so feel free to join in anytime.

Regarding the hull vents, Bill Potter placed them to add fresh air to the bilge to keep it dry, not so much for fuel tank ventilation since the tanks are foamed in (in the I/O and inboard models, it helps to give the engine fresh air). Some members have plugged the openings due to aesthetics or keeping water out, or both. There is dryer hose running in two directions from the aft vents - one foward/aft and one port/starboard. The forward vents on the 23's don't have any hose. Guys that have chosen to close the vents up haven't had any issues so far.

IMO, unless you have a serious water intrusion problem, I'd leave the vent in place.

[Capt Chuck]

Welcome radioshop

Glad to hear your enjoying the CSC web site [img]/images/graemlins/shocked.gif[/img] Even thou you have a Classic Aquasport, I'm also happy to see you have picked up some information from everyone to keep your boat many more years

This site will become addicting

If you search through the old threads you can read other posts on this issue. Some people have different views on plugging the vents but I have discussed this very issue with Mr. Potter and not only did they serve as ventation for the fuel fumes they helped prevent moisture build up and preserved the decks. Scott beat me to it, but also IMO, I would not seal your vents up. It also would be keeping intact the lines of your hull

Good Luck!

[strick]

I had originally planned on plugging the vents and installing a different ventilation system but after giving it heavy thought I've decided to keep the original ventilation system in place. You will need to have a ventilation system for your boat. It will develop condensation if you dont.

Strick

[radioshop]

Thanks for your comments on the matter. Looks like I'll be keeping the vents after all.
Regards,
Jason Swift

[Miles Offshore]

I took this from the coast guard rec boat regulations- from what I get out of it is if you have an underdeck tank you must have an "inlet and outlet" form of at the minimum natural ventilation- mine being an inboard built prior to 1980 mine does not require a blower but it is a must for me having the blower- see what you guys think,btw i used to fish on an old 22'2 that was a great little boat- heres the info from the website-
Federal Requirements and Safety Tips for Recreational Boats

Ventilation

All boats which use gasoline for electrical generation, mechanical power or propulsion are required to be equipped with a ventilation system. A natural ventilation system is required for each compartment in a boat that:
contains a permanently installed gasoline engine;
has openings between it and a compartment that requires ventilation;

contains a permanently installed fuel tank and an electrical component that is not ignition-protected;

contains a fuel tank that vents into that compartment (including a portable tank); and

contains a non-metallic fuel tank.
A natural ventilation system consists of:
A supply opening (duct/cowl) from the atmosphere (located on the exterior surface of the boat) or from a ventilated compartment or from a compartment that is open to the atmosphere;
and an exhaust opening into another ventilated compartment or an exhaust duct to the atmosphere.



All blower motors installed in exhaust ducts must be in working condition of date of manufacture.
Each exhaust opening or exhaust duct must originate in the lower one-third of the compartment. Each supply opening or supply duct and each exhaust opening or duct in a compartment must be above the normal accumulation of bilge water.

A powered ventilation system is required for each compartment in a boat that has a permanently installed gasoline engine with a cranking motor for remote starting.

A powered ventilation system consists of one or more exhaust blowers. Each intake duct for an exhaust blower must be in the lower one-third of the compartment and above the normal accumulation of bilge water.

For boats built prior to 1980, there was no requirement for a powered ventilation system; however, some boats were equipped with a blower.

The Coast Guard Ventilation Standard, a manufacturer requirement, applies to all boats built on or after August 1, 1980. Some builders began manufacturing boats in compliance with the Ventilation Standard as early as August 1978. If your boat was built on or after August 1, 1978 it might have been equipped with either (1) a natural ventilation system, or (2) both a natural ventilation system and a powered ventilation system. If your boat bears a label containing the words "This boat complies with U.S. Coast Guard safety standards," etc., you can assume that the design of your boat's ventilation system meets applicable regulations.

Manufacturers of boats built after 1980 with remote starters are required to display a label which contains the following information:
Warning:
Gasoline vapors can explode. Before starting engine, operate blower at least 4 minutes and check engine compartment bilge for gasoline vapors.

All owners are responsible for keeping their boat's ventilation systems in operating condition. This means making sure openings are free of obstructions, ducts are not blocked or torn, blowers operate properly, and worn components are replaced with equivalent marine type equipment.

[FELLOW-SHIP]

Ha Radioshop
Let me Vent my opinion here as well. I looked at most the new outboard boats on the marked and saw no vents on the sides of their boats. They usually use smaller vents under the cap close to the transoms to vent their boats from gas fumes. I have a Potter 23’ which have 4 hull vents which I filled in all of them. I did add one vent under the center consol and have vent arrears on either side of the transom area under the cap close to the two storage boxes. I personally didn’t like the look of the vents. I could also open up the two access hatch doors by those two storage hatches as will if I needed to.
http://www.classicseacraft.com/mcgovern23page3.htm
FellowShip [img]/images/graemlins/cool.gif[/img]

[Mark]

I wonder why there were no vents in some of the SeaCraft's of other lengths that have fuel tanks below the deck and that would also incur moisture. My 18' was a '76/77, no vents, and yet there was a lot of gas under the floor?

As to the 23's, what about putting the vents on the inside instead of on the outside when undergoing a redo? Air would still be pushed through there and the aesthetics would be improved...