Professional BoatBuilder - April-May 2018

10 PROFESSIONAL BOATBUILDER

LETTERS

Provided the valve material meets this

standard, it is acceptable. Otherwise, a

material with greater resistance to high

temperature may be required.

Bertram Is Back

To the Editor: 

I noted with interest the image of the

prop and strut on page 27 in “Bertram Is

Back” (PBB No. 171).  e prop nuts are

on backward but not commented on.

Since the SAE standard was established

in either 1927 or 1929, the persistence of

the incorrect placement by reputable

boatbuilders is strange. Additionally, the

sha overhang looks as if it may be

excessive. 

Rex Miller CMS

Telrex Marine Services

Mundelein, Illinois

Aaron Porter responds:

I thank Mr. Miller for his close read-

ing and perusal of Dan Spurr’s article

about Bertram’s latest renaissance. His

observation about the prop nuts is cor-

rect.  e which-nut- rst debate is not

new to our Letters, Etc. column. Most

especially I would refer readers to PBB

technical editor Steve D’Antonio’s

extensive exchange on the subject in

response to an insightful letter from

Wesly Lilly, president of Saturn Marine

Engineering. It starts on page 12 of PBB

No. 121. Additional correspondence is

in PBB Nos. 122, 123, and 124 on pages

9, 7, and 8, respectively. At that time, we

received multiple notes and calls from

ship and commercial tug mechanics

asserting that—contrary to D’Antonio’s

advice, ABYC standards, and a half

dozen engineering, military, and man-

ufacturer texts—on larger vessels the

big nut should be installed  rst. So be

prepared to see both sequences in

application out there. Indeed, a photo

on the facing page of Spurr’s article

shows the nuts in a “proper” sequence

on a sha , though no prop is installed.

Which illustrates the risk of looking at

anything in a build shop and thinking

it’s a  nal assembly.

To read those letters in the back issues

listed above, it’s now easier than ever at

our online back-issue archive (http://

backissues.proboat.com).

systems shall comply with the perfor-

mance requirements of SAE J2006,

Marine Exhaust Hose, or UL1 129, Stan-

dard for Wet Exhaust Components for

Marine Engines. All other exhaust sys-

tem components shall meet the per-

formance requirements of UL 1 129,

Standard for Wet Exhaust Components

for Marine Engines.”

and modulus of elasticity, it’s unlikely

that it could endure exposure to dry

exhaust. All wet exhaust components

should be capable of withstanding

exposure to dry exhaust for at least as

long as the hose and water li mu er

are. ABYC Guidelines on this subject are

fairly clear:

“P-1.7.1.5. Hose used in wet exhaust

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