Seaward Water Heaters for marine applications like boats or RVs
Seaward Seaward hot water heaters running on shore power or off heat exchangers
  • Seaward Water Heaters for marine applications like boats or RVs

Seaward Water Heaters

Seaward marine water heaters run on 110/120V AC shore power or convert engine heat with heat exchangers while underway to efficiently create hot water. These water heaters can hold anywhere from 6-11 gallons of water.

All Seaward heaters have galvanized steel exterior with aluminum tank interiors, hold down brackets and ignition protection. Dual wall heat exchangers are front mounted on "F" models and rear mounted on "S" model water heaters.

$453.00 / ea
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Tech Spec Product Info User Generated Content


  • Combination electric/heat exchanger or electric.
  • Inner tanks made from Alcoa Alclad aluminum alloy.
  • Hold down brackets welded to inner tank.
  • UL (120v models) or CE (240v models) approved.
  • Temperature pressure relief valve.
  • Magnesium anodes available.
  • Large 1/2-inch drain valve.
  • Exteriors are marine galvanized steel.
  • Ignition protected.
  • T & P drain tube included.
  • Tempering valves available.


Available in unfinished or white, with the option of heat exchanger in front or rear.
Item #  Heat Exchanger  Capacity  Overall Size" 
SWD F600  Front  6 Gallons  13W x 19D x 13H 
SWD F600W  Front/White  6 Gallons  13W x 19D x 13H 
SWD F1100  Front  11 Gallons  16W x 22D x 16H 
SWD F1100W  Front/White  11 Gallons  16W x 22D x 16H 
SWD S600  Rear  6 Gallons  13W x 19D x 13H 
SWD S600W  Rear/White  6 Gallons  13W x 19D x 13H 
SWD S1100  Rear  11 Gallons  16W x 22D x 16H 
SWD S1100W  Rear/White  11 Gallons  16W x 22D x 16H 
WARNING: These products may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to

BRAND: Seaward
Type: Water Heater
4.2 13

Poor QC and might freeze


The holes in the sheet metal did not align with the water pipes so I could not connect it to the engine hoses. I checked to see how well it drained the potable water to prevent freezing and found that it still held over a quart of water when "drained". I returned it without any hassle.


Marion MA


not functional


Just bought and returned a 6 gallon model. The sheet metal housing has holes just big enough for a socket wrench to put in the pipe fittings but the ports in the tank don't align with the holes in the housing so one cannot assemble it. The instructions seem to say the draining the fresh water tank with the cheap drain valve will protect it from freezing damage. I checked and measured that that still leaves 1.5 gallons of water in the tank. The instructions later recommend that the whole fresh water system be winterized with antifreeze - including the 6 gallons in the water heater. I asked the US distributer for clarification but have not received an answer. When I bought my old boat 15 years ago it had one of this brands water heaters. I drained it with the drain valve but it broke during the second winter. Thought it was just old age but now I know that doesn't really protect it. I bought a different brand that also broke but not until last winter. Just installed a third brand and will do a review of it next year.


Marion MA


great product and it was a smooth purchase


Overall turned out to be a good purchase experience but went into it a little skeptical. I had to purchase without knowing what I was going to be charged for shipping which is a little scary when dealing w a company for the first time. I did put in the comments section that my order was contingent on shipping charges and they sent an email promptly letting me know what that would be. Shipping was fair and fast. Would do business with them again.




I would by again


everything what they said was true




It's the same, but not the same :)


Replaced 17 year old water heater with this 11 gal. of what I thought was the same make and model. Looks the same. Screw holes for mounting were not in same locations so had to pilot drill new holes for new screw locations. This unit is also a little bit bigger than last one. All connections are in the same location and fit perfectly. No problem installing and connecting it other than where boat manufacturer decided to put it. Works great, just follow nicely written book of instructions.

Capt'n Jack

Narragansett Bay RI


It made replacing old heater simple


Same basic design as Admiral.Resued old fittings & improved rust control. Easy old out & new in without any alterations to boat.


Northern Indiana

grateful to find one at a fair price


fast shipping and I needed that due to no hot water, thanks


Grand Cane, La


I hope I don't have to buy this product,


We installed our water heater in our sailboat


Massena, NY

Great Heater


I am very happy with this purchase so went live this weekend and we can actually see steam on a hot summer day...never had that before.


Norwalk CT


I would buy this item again


Depending on location, very easy to install.

Boat Nut

Lake Geneva, WI.


Seaward Water Heaters



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