9
SEP30-40/125S2
5467-2 - 2018
Master
5
Some boats is very fl at bottomed and has a very shallow draft in
the bow section. It might be very diffi cult not to say impossible to
fi t a tunnel thruster the usual way, at least as far forward in the
hull as a thruster should be (Fig. 1).
However, it is possible to install a tunnel thruster even when the
hull does not directly support the fi tting of a tunnel.
This is done by fi tting the tunnel halfway into and halfway under-
neath the exisiting hull and then strengthen it and smoothening
the waterfl ow by moulding a bulb around / underneath the tunnel.
This will allow installation in good position on the boat, maintaining
the reliability and space advantages of a tunnel thruster.
This can also be a good installation method for fl at bottomed
barges to avoid extremely long tunnels and huge oval tunnel
openings in the hull.
If the tunnel is over 250 cm long at its deepest point, it is recom-
mend that is is supported by a bulkhead as suggested in fi g. 2
and 3.
Tunnel installation in fl at bottomed hulls
EN
Tunnelinstallasjon i fl atbunnede skrog
NO
Noen båter har brede skrog som ikke stikker dypt i baugen.
Skrogtypen gjør det vanskelig å installere en thrustertunnel på
vanlig måte, spesielt med tanke på å plassere den langt nok frem
(Fig. 1).
Thrustertunneler kan allikevel installeres i de fl este båter. Dette
gjøres ved å la en del av tunnelen stikke ut i underkant av skro-
get. Tunnelen er sterk nok til dette, og thrusteren blir plassert lav
nok og langt nok fremme.
Dette gjøres ved at øvre halvdel av tunnelen støpes inn i skroget,
tunnelen styrkes i underkant ved å støpe en kul rundt tunnelen og
jevne den ut mest mulig.
Denne installasjonen kan også være gunstig for båter med fl ate
bunner, for å unngå ekstremt lange tunneler og store ovale tun-
nelåpninger.
Er tunnelen over 250 cm lang, anbefales at den støttes opp av et
skott som vist på fi g. 2 and 3.
C
D
Fig. 2
Fig. 3
16
SP 75 Ti / SP 95 Ti / SP 125 Ti
2.5.1- 2007
Segelboote weisen häufig einen Rumpf in Rennform auf, was
einen sehr flachen Rumpf im Bugbereich bedeutet. Es ist daher
schwierig oder fast unmöglich, den Tunnel an der gewünschten
(effektivsten) Stelle, also möglichst weit vorne im Bug zu plazieren
(Fig. 1).
Trotzdem ist es vielfach möglich unter diesen Bedingungen eine
Bugschraube einzubauen, auch wenn der Tunnel damit nicht völlig
vom ursprünglichen Rumpf umgeben ist.
Der Tunnel wird zur Hälfte in den bestehenden Rumpf integriert,
die andere Hälfte geht über diesen hinaus. Der Tunnel muß nur
noch verstärkt und strömungsgünstig abgerundet werden.
Dies erlaubt eine Installation in geeigneter Position bei Nutzung
der Zuverlässigkeits- und Platzvorteile einer Tunnelschraube.
Diese Installationsart wird von einigen der weltweit führenden
Segelboothersteller verwendet und führt meistens nur zu einem
äußerst geringen bzw. gar keinem Geschwindigkeitsverlust.
Diese Bauweise ist auch für Barkassen (z.B. Flußboote) mit
flachem Bug geeignet, um einen zu langen Tunnel und große
ovale Tunnelöffnungen im Rumpf zu vermeiden.
Installation in Segelbooten
D
Tunnel installation in sailboats
Fig. 1
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Many sailboats have a racing type hull which means that it is very
flat bottomed and has a very shallow draft in the bow section. It is
thereby very difficult not to say impossible to fit a tunnel thruster the
usual way, at least as far forward in the hull as a thruster should be
(Fig. 1).
However, it is possible to install a tunnel thruster in most sailboats,
even when the hull does not directly support the fitting of a tunnel.
This is done by fitting the tunnel halfway into and halfway under-
neath the existing hull and then strengthen it and smoothening the
water flow by moulding a bulb around / underneath the tunnel.
This will allow installation in good position on the boat, maintaining
the reliability and space advantages of a tunnel thruster.
This installation is being used by some of the world’s largest sailboat
builders, and has been proven to give little to no speed loss for
normal cruising.
This can also be a good installation method for flat bottomed barges
to avoid extremely long tunnels and huge oval tunnel openings in the
hull.
Master
6
Boat builders having thrusters as standard, or delivering a large
portion of one or more models with thrusters, have the opportu-
nity to make a perfect tunnel installation, while saving both time
and money on each installation (Fig. 1).
The solution is to make an insert / plug in the hull mould, which
prepares the hull for an easy tunnel installation with features for
maximum thrust and minimal drag (Fig. 2).
This insert / plug in the mould is not very diffi cult to make, and as
it will have to be a "bolt on" in the mould in order to get the boat
out, you can still make boats without this hull feature. (Some boat
builders have this in the hull also on boats that are delivered with-
out a thruster as they know many people will fi t this later)
By having a fl at surface to fi t the tunnel to, the installation time
and cost for the tunnel will also be reduced as:
- it is very easy and fast to cut the now circular hole for the tun-
nel
- it is easier to mould inside all around the tunnel
- you save tunnel length
The plug in the mould can also be made so that it can be a fi xed
part of the mould, but the rounded end option must then be made
later to get the hull out of the mould (Fig. 3&4).
Series production installation
Fig. 1
Fig. 3
Fig. 2
Fig. 4
EN
a1
b
a1
a2
a2
b
a1 a2
d
d
c1
c2
c2
c3
d
b
c3
c1
D
Radius =
D x 0,1
A
a1
b
a1
a2
a2
b
a1 a2
d
d
c1
c2
c2
c3
d
b
c3
c1
Båtbyggere som har trustere som standard eller leverer en eller
fl ere modeller med valgfri truster i stort antall har mulighet for å
lage en perfekt tunnelinstallasjon og samtidig spare tid å penger
(Fig. 1).
Løsningen er å lage en plugg/innsats i formen, som klarrgjør
skroget for anklest mulig tunnelinstallasjon og som samtidig har
perfekt utforming for maksimal trust og minimal motstand (Fig. 2).
Pluggen/innsatsen er ikke komplisert å lage og siden den må
skrus fast i formen på grunn av slipp kan skrogene fremdeles
lages uten denne løsningen. (Enkelte båtbyggere velger også
denne løsningen på båter levert uten truster da de vet at mange
vil velge å ettermontere en truster)
Ved å ha en rett fl ate å montere tunnelen på, reduseres installas-
jonstiden og kostnaden for tunnelen siden:
- det blir veldig enkelt og raskt å skjære ut det nå sirkulære hullet
til tunnelen
- det er enklere å støpe inn tunnelen langs hele omkretsen
- du sparer lengde på tunnelen
Pluggen i formen kan også lages på en slik måte at den inngår
som en fast del, men da må avrundingen lages etterpå for å
oppnå slipp i formen (Fig. 3&4).
Installasjon ved serieproduksjon
NO
