A Winter Project: A Fog Horn

A Winter Project
By Ted Walsh
‘When we took on the stewardship of the Black Star, the only piece of safety equipment missing hap-
pened to be a horn. Having experimented with a number of options, we have come up with a mechanical a.
horn that I thought might interest other FSS members. wd. gy
The project presented here is not the most effortless way to provide a horn for a vessel, lon e
but is rather, a fun winter project that can add to the uniqueness of your own boat. It does – 4 e, i
have advantages in that the horn can be secured to the house so no one in the cockpit oF CHP a
gets deafened and there is one less thing rolling around underfoot. It can also be Ses aa
stowed out of way when not needed and you won’t run out of propellant. Pull out oY 3 3 _
the plunger, and when you push it back in you get a blast of the hom… at ok @ a’ ae Soe
Box lid held on ey ;
dt” AG: Dk…
ie f Lad
e f AM ~
Pump and airhorn tb AV AS A , i ™
version ——— ey f RY} SN
( ) ik aN
aw aS 4 Basically you are going to make a box that can be secured to the
‘T) ¥ H 7 {handrail on the cabin top by a pair of “ears” held to the box of the horn
Ne t ‘4, by wing-nuts. The top of the box is secured with screws to make it easy
q AY By a to open in the event that repairs are needed.
– a
Wingnuts a ¢] Ss The drawings and diagrams presented here show what we made
2 y for our sloop. I hope they might serve as guidelines for anyone
4 F & wishing to make a horn of their own. You would need to make
Box with built 3 q X adjustments to the design to suit your vessel. For example,
in brackets to A the angle between the bottom of the box and the side that
id pep ome —e will go against the handrail will be determined by the angle
a of your cabin-top and the handrail on your boat.
6%” ot
e lee
The Hom: We went with a plastic air hom made by Falcon > =
($18.95) but for a more traditional sound, a brass == *
straight horn works well (I have experimented). These a
are available in different sizes from 6 inches long ee ae) ;
($11.95) to 18 inches long ($25.95). The best sourceI }_ g-—~_ oy ts
know for these is a company called Lark In The Morn- ay ~ fa
ing. Of course you can just order a horn and then blow LOY Some basic dimentions == |
on it but then what would you do for a winter project? If you a recta! Led plat arg
really want to get carried away you can get a traditional air powered siren Lagi) :
made by the Acme Siren Co. ($76.50 through Garrett Wade). a O

Bronze washer ‘Rubber Pump construction and parts ¢
Lacehar washer ea Gay ral
ket =e
& ae Glue 1/4” PVC cap onto PVC Pipe, then drill Drill center hole in second cap for bronze push rod.
——— hole and srew threaded hose coupling into Drill for aditional holes to let air into the pump.DO —~ =-e-
the hole NOT glue on the cap. you need to be able to remove f* 4
the cap to maintain the pump.
The Pump: The air horn that we bought came with a little pump but we built a more powerful one using 1 % inch schedule 40
PVC pipe and two caps, a piece of % bronze rod, a few washers and bronze nuts, a threaded-to-male barb hose coupling, and a piece
of leather formed into a cup shaped gasket. The total cost for all the parts came to less than $20. You will, however, need to have a
tap-and-die set to cut threads in either end of the bronze rod. The only two tricky parts about making the pump are making the
leather gasket and threading the bronze push rod. The trick to threading the bronze rod is that you need
a good vise to hold the rod so you can use both hands on the thread cutter.
J 7 v4 7, To form the leather gasket you will need a piece of leather about 3/16 thick and about 4 inches in
om i