Contest Compass Steel Boat

[Wielingen]

Dear All,

I've got a 1953 steel sailing boat. Since it has only been used by the previous Dutch owners on Dutch inland waters, it does not have a compass. The boat is seaworthy, though.

I thought and found a Sestrel Moore compass. However, there is no good spot to install it.

That's why I'm thinking of buying an over the counter bulkhead mounted Plastimo Contest compass. Compensation magnets are available and the plan is to buy them to cancel out the deviation caused by the boat.

Does anyone know or have experience with compensated bulkhead compasses on steel boats? Does it work? Will I get treasonably reliable readings from it?

Thanks for sharing the knowledge!

Wielingen

[StuM]

From the horses mouth (https://www.plastimo.com/en/support/...avigation.html
My boat has a steel or ferrocement hull. Which compass should I choose?

• 
  No compass can answer this specific requirement alone. It is necessary to call for the services of a professional compass adjuster who will set up a compensation system relevant to your boat.

[Wielingen]

Thanks for the reply!

[Rumrace]

We had this Steal Dive boat in Georgian Bay the Orkney Isle. We had two small cannon balls about 8” OD 7 inches from the compass. Georgian Bay is this glacier scrapped band of iron. So now the boats in Oakville Lake Ontario. Sand the end of an ancient reef. the compass is off 11 degrees.

[StuM]

Originally Posted by Rumrace

We had this Steal Dive boat in Georgian Bay the Orkney Isle. We had two small cannon balls about 8” OD 7 inches from the compass. .

Yep, I've done passages on a couple of steel yachts. They both had big compensator balls on either side of the compass (both were binnacle mounted, not bulkhead mounted). Not sure how you'd compensate a bulkhead mounted Plastimo but you'd still need some hefty lumps of metal, not the little compensator accessory they sell.

[psk125]

Like StuM says. Compases on steel boats can be compensated to make them more accurate, but it needs to be done properly and checked on a regular basis. Vibrations in steel ships (from things like running the engine...) turn the entire hull into a magnet, (see deGaussing ) which would obviously mess up compasses on board, even if they had been compensated earlier.

[Rumrace]

My plastic Sea Rays in Georgian Bay we compensated as per charts before GPS.
The Dive boat was a retired fishing boat Modified for easy stern entry and could hold 22 divers and 2 tanks each.
The compass was on a pedestal ahead of the wheel. I’m pretty sure it is a brass bar and two balls on the ends. It was adjusted in Oakville by the owner.

[Rumrace]

The other steel boat do not have antiques on them. Apparently West Marine has them. 500-900$
personal taste I like Richie but shop around
These work way better than cannon balls

[mvmojo]

Take a look at a satellite compass like the Garmin. Not a whole lot more $$$ than a compensated magnetic compass and you can interface it to feed radar, chart plotter, etc.

[Benz]

There is a thorough and very informative chapter in Bowditch regarding compass adjustment on steel boats. I would buy the Ritchie pictured above and hire a professional to adjust it.
If you get it hauled, try to have the keel oriented north-south while you violently sand off the bottom paint. That will help with keeping your compass well-adjusted.