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Product Details

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.

Tech Specs
Item # Heat Exchanger Capacity Overall Size"
SWD F600Front6 Gallons13W x 19D x 13H
SWD F600WFront/White6 Gallons13W x 19D x 13H
SWD F1100Front11 Gallons16W x 22D x 16H
SWD F1100WFront/White11 Gallons16W x 22D x 16H
SWD S600Rear6 Gallons13W x 19D x 13H
SWD S600WRear/White6 Gallons13W x 19D x 13H
SWD S1100Rear11 Gallons16W x 22D x 16H
SWD S1100WRear/White11 Gallons16W x 22D x 16H
Info & Guides
Available in unfinished or white, with the option of heat exchanger in front or rear.

Technical Information

  • 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.

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 www.P65Warnings.ca.gov

Reviews for Seaward Water Heaters

10 of 14 Reviews

June 30, 2021

Check out the threading on the ports for machining damage.
By Waterdog from Annapolis

Verified Purchase

I had to purchase this item twice - once from an alternate vendor. The first unit had damaged threads. In examining their stock that supplier found all other units in stock had the same issue. The second unit from Jamestown similarly had bad machining on the threads of one port, but I was able to use it. There seem to be some quality issues on the manufacturing end. Jamestown is always great as a supplier and handled the order, shipping, etc. perfectly.

Bottom Line No, I would not recommend to a friend

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August 14, 2019

Poor QC and might freeze
By rogeruu from Marion MA

Verified Purchase

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.

Bottom Line No, I would not recommend to a friend

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July 25, 2019

not functional
By RogerUU from Marion MA

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.

Bottom Line No, I would not recommend to a friend

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July 1, 2019

great product and it was a smooth purchase
By Carver from TN

Verified 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.

Bottom Line Yes, I would recommend to a friend

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August 16, 2018

I would by again
By noone from boston

Verified Purchase

everything what they said was true

Bottom Line Yes, I would recommend to a friend

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July 20, 2015

It's the same, but not the same :)
By Capt'n Jack from Narragansett Bay RI

Verified Purchase

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.

Bottom Line Yes, I would recommend to a friend

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May 7, 2015

It made replacing old heater simple
By Syracruiser from Northern Indiana

Verified Purchase

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


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April 20, 2015

grateful to find one at a fair price
By bullfrog from Grand Cane, La

Verified Purchase

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

Bottom Line Yes, I would recommend to a friend

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July 22, 2013

I hope I don't have to buy this product,
By Ron from Massena, NY

Verified Purchase

We installed our water heater in our sailboat


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June 17, 2013

Great Heater
By Chip from Norwalk CT

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

Bottom Line Yes, I would recommend to a friend

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