Knotmeter thru-hull installation.

[Stan W]

I ended up getting a Standard Horizon knotmeter. The process of installing the plastic thru-hull transducer seems straight forward enough, but I am not sure of the best location. The boat is a '79 CD 28 sloop. The manual suggests forward of the keel, in a location with minimal dead rise, away from turbulence caused by other fittings, and in a location that will remain submerged when the boat is heeled. Any suggestions?



smwheatley@capecod.net

[Jack Bego]

Mine is located under the starboard vee berth close to the head bulkhead (CD 28)

Jack Bego

[Duncan Maio]

Any suggestions?

Stan:

On my CD27, the knotmeter transducer is in the port side of the keel, and is accessed through the floorboard just forward of the companionway stair. this location has the advantage of allowing the transducer to be removed (and replaced with the plug that came with my SR Mariner unit) for service without flooding the boat. Cabling to the port side of the cockpit is also simplified.

Duncan Maio
s/v Remedy
CD27 #37
Bristol, RI



mail@mysticmarine.net

[Larry DeMers]

Hi Stan,

I just completed this task on our CD30 this past weeekend, and like Jack, mounted the transducer (Autohelm ST60 Tri-Data) in the port side of the keel root, exactly opposite the Dynaplate and under the salon's access grate to the bilge. The advantages (besides those mentioned by Jack) are that you are placing the impellor in the laminar flow area of the keel, which should be constant and unbroken by boat movement, unless the keel were to be stalled out (would have to be broadside to the flow of water). We have our launch this weekend, so don't have any actual data to report yet.

Cheers!

Larry DeMers
DeLaMer
Cape Dory 30 ~~Sailing Lake Superior~~

I ended up getting a Standard Horizon knotmeter. The process of installing the plastic thru-hull transducer seems straight forward enough, but I am not sure of the best location. The boat is a '79 CD 28 sloop. The manual suggests forward of the keel, in a location with minimal dead rise, away from turbulence caused by other fittings, and in a location that will remain submerged when the boat is heeled. Any suggestions?

demers@sgi.com

[Frank Vernet]

On Sirius, our CD33, the speed impeller is in the port side of the keel, and is accessed through the floorboard just forward of the companionway stair (same access panel for the bilge pump and waste water tank). This makes it easily accessible and like Duncan's boat makes it possible to remove/repair/replace it w/o flooding the boat as the incoming water goes straight into the bilge where...hopefully...it is promptly removed by the bilge pump!

Frank Vernet
s/v Sirius, CD33
Annapolis, MD

[Neil Gordon]

>>... makes it possible to remove/repair/replace it w/o flooding the boat as the incoming water goes straight into the bilge ...<<

The flapper valve on the thru hull keeps most of the water out. I can pull the unit for cleaning and catch most of what gets by in a sponge.


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167



neil@nrgordon.com

[Frank Vernet]

>>... The flapper valve on the thru hull keeps most of the water out ...<<

Thanks Neil:
Great tip. I always made sure I scrubbed that little impeller when anchored and snorkeling in the clear Caribbean waters that surround Puerto Rico and the Spanish Virgins. Won't be nearly as pleasant in the Chesapeake Bay. I think I'll try it from the inside going forward.

Frank Vernet
s/v Sirius, CD33 #84
Annapolis, MD

[Frank Vernet]

>>... The flapper valve on the thru hull keeps most of the water out ...<<

Thanks Neil:
Great tip. I always made sure I scrubbed that little impeller when anchored and snorkeling in the clear Caribbean waters that surround Puerto Rico and the Spanish Virgins. Won't be nearly as pleasant in the Chesapeake Bay. I think I'll try it from the inside going forward.

Frank Vernet
s/v Sirius, CD33 #84
Annapolis, MD

[Jay Hubbard]

I ended up getting a Standard Horizon knotmeter. The process of installing the plastic thru-hull transducer seems straight forward enough, but I am not sure of the best location. The boat is a '79 CD 28 sloop. The manual suggests forward of the keel, in a location with minimal dead rise, away from turbulence caused by other fittings, and in a location that will remain submerged when the boat is heeled. Any suggestions?

My 79 CD 28 has thru hull under starboard V berth about a foot ahead of the bulkhead and it works fine.



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