Dave Gerr - Boat Mechanical Systems Handbook-How to Design, Install, and Recognize Proper Systems in Boats

Convert gallons per minute (gpm) to cu. ft./

min., or liters per minute (L/min.) to m^3 /min.

Multiply gpm × 0 .134 to get cu. ft./min.

Multiply L/min × 0 .001 to get m^3 /min.

Find the minimum and maximum water
flow in gpm or L/min. from the engine specs
and convert to cu. ft./min. or m^3 /min.
Find most likely water flow (MLWF) using
the following formula.

Formula 8-3. Most Likely Water Flow
(MLWF)

MLWF =[0. 67 ×(max. flow – min. flow)]

+ min. flow

Where

max. flow =maximum water flow,

cu. ft./min or m^3 /min.

min. flow =minimum water flow,

cu. ft./min or m^3 /min.

Find the cross-section area of one keel-

cooler channel, or one-channel area (1CA), in

square feet or m^2.

Find flow velocity (FV) using the follow-

ing formula.

Formula 8-4. Flow Velocity (FV)

FV=MLWF ÷(1CA ×no. channels

×60 sec./min.)

Chapter 8: Engine Cooling Systems and Their Exhausts

TABLE 8-3. KEEL-COOLER TUBE LENGTH (cm/bhp AND cm/kW) COPPER OR COPPER-
NICKEL TUBE UP TO 85°F (29.4°C) SEAWATER TEMPERATURE
ROUND TUBE, APPROX. 1.5 TO 2.5 mm THICK

Generators & Free-Running

Stationary Slow-Moving Under 8 Knots Over 8 Knots

Tube OD, mm cm/bhp cm/kW cm/bhp cm/kW cm/bhp cm/kW cm/bhp cm/kW

28 10. 622. 229. 715. 520. 812. 416. 710. 6

27 11. 023. 030. 816. 121. 612. 917. 311. 0

26 11. 423. 932. 016. 722. 413. 417. 911. 4

25 11. 824. 833. 317. 423. 313. 918. 711. 8

24 12. 325. 934. 718. 124. 314. 519. 412. 3

23 12. 927. 036. 218. 925. 315. 120. 312. 9

22 13. 428. 237. 919. 826. 515. 821. 213. 4

21 14. 129. 639. 720. 727. 816. 622. 214. 1

20 14. 831. 041. 621. 729. 117. 423. 314. 8

19 15. 632. 743. 822. 930. 718. 324. 515. 6

18 16. 434. 546. 324. 132. 419. 325. 916. 4

17 17. 436. 549. 025. 634. 320. 527. 417. 4

16 18. 538. 852. 027. 236. 421. 729. 118. 5

15 19. 741. 455. 529. 038. 923. 231. 119. 7

14 21. 144. 459. 531. 041. 624. 833. 321. 1

13 22. 747. 864. 133. 444. 826. 835. 922. 7

12 24. 651. 769. 436. 248. 629. 038. 924. 6

11 26. 956. 575. 739. 553. 031. 642. 426. 9

10 29. 662. 183. 343. 558. 334. 846. 629. 6

932. 969. 092. 548. 364. 838. 651. 832. 9

837. 077. 6 104. 154. 372. 943. 558. 337. 0

742. 288. 7 119. 062. 183. 349. 766. 642. 2

649. 3 103. 5 138. 872. 497. 258. 077. 749. 3

559. 1 124. 2 166. 686. 9 116. 669. 693. 359. 1

NOTE:Tubes are mounted so seawater flows freely around the entire tube surface.

NOTE:Square tubes may be 78 percent of the length of round tubes.

Formula 8-3.

Formula 8-4.