The Pan Oceanic 46 models built in Taiwan came with manual Barient 32 primary and Barient 26 secondary winches. When looking at replacing the winches we decided to upgrade to some newer Lewmar Ocean winches. The Pan Oceanic has a cutter rig so the headsails are not that big. The original two speed Barient 32 primary winches were somewhat oversized.
Sizing a Winch
Adding winches to a sailboat is based on the size of the load the sail will exert on the winch. Most winch manufacturers provide graphs and tables to determine roughly what size of a winch should be used on various sized sailboats and wind loadings.
Loading will differ depending if the winch is being used as a primary headsail, staysail or mainsail application. The largest load on the winch will most likely come from the genoa or head sail. Searching the internet I found some calculations for determining wind force based on the sail area.
Wind pressure per square foot equals .00256 x wind speed in mph squared. This means that the force on the sail is magnified by the square of the wind speed.
SL = SA x V2 x 0.00431
SL = Sheet loading in lbs
SA = Sail Area in square ft
V = Wind speed in knots
Wildthing has a cutter rig so the headsail is only 550 square ft. We will use 30 knots as the maximum wind speed. The genoa will most likely be reefed prior to 30 knots so the wind speed will be for worst case.
SL = 550 x 30sq x 0.00431
SL = 2133 lbs
Lewmar provides the table below to roughly size the winch based on the boats length and sail area size. To more accurately size the winch the specific winch safe working load (SWL) should be determined. The instruction manual for the Lewmar winches show the SWL of the various electric winches as shown below.
Lewmar Ocean 46 SWL = 2645 lbs/ 1200 kg
Lewmar Ocean 48 SWL = 2756 lbs/ 1250 kg
Lewmar Ocean 50 SWL = 3000 lbs/ 1360 kg
The graph below shows for a 46 foot sailboat we would need a winch size of 55 at a minimum. Looking at the sail size of 550 square feet shows we need a minimum size of a 45. A Lewmar Ocean 46 would have possibly worked but we selected a Lewmar Ocean 48, the next size up, for a safety margin of 22%. Both of these sizes were available on the used market.
So the selection of the Lewmar Ocean 48 (SWL 2756 lbs) should be large enough to handle the 550 square foot genoa loading of 2133lbs.
Electric Conversion
Converting Lewmar winches to electric can be done for sizes 40 and larger. Lewmar winches older than 2000 cannot be converted to electric. Conversion kits are readily available at most marine stores. The cost of the conversion kits are often as expensive as the winch itself.
The kits consist of a new base plate, a drive unit, gear box, contactor, circuit breaker and switch. I did not purchase the kits as they are almost as much as buying a new winch.
I was able to purchase one electric Lewmar Ocean 48 with a 700 watt electric motor on eBay for $1500. I also purchased an electric Lewmar Ocean 46 with a 1500 watt motor for $1800. The plan was to convert the 46 into a manual winch and use the motor to power a Lewmar 48.
I waited a few months and sure enough another manual 2 speed Lewmar 48 came available for $600. The drive shaft for the 46 and 48 are the same so I could reuse that and the motor to drive the 48. The other item I needed was the electric winch base with the bearing. I found one of those on eBay for $150 in Great Britain. That arrived in a few weeks so my plan was coming together.
Installation
Installing the electric winches required that a large 2 1/2 inch whole be cut in the deck for the drive shaft and electric motor to attach below deck. The Pan Oceanics have a large slanted winch bases built on the bullworks in the cockpit. We followed the Lewmar winch installation guide to make sure we oriented the winch main drive gear towards the back of the winch to take the maximum load. The winch motor can be oriented in one of 4 positions below deck at 90 degree increments. Make sure to measure twice and cut once!
We pulled off the old winches, filled the holes and drilled new holes to mount the winch bases. Lewmar suggest that the main drive gear of the winch be mounted in line with sheet lines.
We oriented the winch base and made sure we had room below deck for the drive motors and gearbox. We ended up cutting out some of bulkheads in the cockpit lockers to make room for the motors.
We used butyl rubber on the deck plate to waterproof the installation.
The port side Lewmar two speed manual winch |
I wired the winches on one 12 volt circuit which is powered from the house bank batteries. I used 2/0 tinned marine cable to power the winches. The circuit runs through a 300 amp shut off switch and is protected by a Blue Seas 150 amp circuit breaker.
This shows the cabling coming out from under the cockpit to the port side winch. The positive, red conductor was put in plastic conduit to prevent any damage or short circuits.
This shows the port motor with the positive and negative connections.
For one of the winches I decided to try something a little different. Instead of buying another Lewmar Type E contactor. I purchased a winch solenoid on Amazon for only $19.00.