sailorman
Well-Known Member
Re: \"Over the hump\"
ITS BETTER TO BEG FORGIVENESS THAN SEEK PERMISSION
NO IS NO!
<hr width=100% size=1>
ITS BETTER TO BEG FORGIVENESS THAN SEEK PERMISSION
NO IS NO!
<hr width=100% size=1>
"Over the hump"
- Thread starter scorch
- Start date
Duncan_Hamble
Active Member
Re: \"Over the hump\"
Many replies have suggested adding weight in the bow. This may help but, before you try this try to get as much weight out of the boat as possible - tools - beer - spares - wellies etc as weight is the real killer of speed on all planing boats especially when power is marginal. Then try again. With the boat lighter it may plane at a lower speed.
Too much weight in the bow may cause steering problems when/if the boat does plane and when going down sea.
Trimming the drives in may also cause the same problems.
Propellers will also be critical as is how dirty the bottom is.
4107s can be allowed to rev to about 3600 for planing applications with 3000 as a max continuous rating - check your manual first though. A change of propellers may help.
I feel that with this size of boat and this power your planing performance will be marginal. But give it a go.
I used to work in a boatyard as a schoolboy and the boss had a Cleopatra 30 with twin 4107s. When new it would plane at about 12 knots with a maximum of about 14. Once brought up onto the plane you could throttle back and cruise at about 12 knots. However, any sort of sea would knock it off the plane. So you may have luck - but still marginal.
Parents had a Senior 32 with twin 4107s. 10 knots flat out whatever we tried!
I would look at removing as much weight as possible, distributing it to best effect, cleaning the bottom, trying some propellers and perhaps still having to settle for only being able to plane in flat conditions if lucky.
Duncan
<hr width=100% size=1>
Many replies have suggested adding weight in the bow. This may help but, before you try this try to get as much weight out of the boat as possible - tools - beer - spares - wellies etc as weight is the real killer of speed on all planing boats especially when power is marginal. Then try again. With the boat lighter it may plane at a lower speed.
Too much weight in the bow may cause steering problems when/if the boat does plane and when going down sea.
Trimming the drives in may also cause the same problems.
Propellers will also be critical as is how dirty the bottom is.
4107s can be allowed to rev to about 3600 for planing applications with 3000 as a max continuous rating - check your manual first though. A change of propellers may help.
I feel that with this size of boat and this power your planing performance will be marginal. But give it a go.
I used to work in a boatyard as a schoolboy and the boss had a Cleopatra 30 with twin 4107s. When new it would plane at about 12 knots with a maximum of about 14. Once brought up onto the plane you could throttle back and cruise at about 12 knots. However, any sort of sea would knock it off the plane. So you may have luck - but still marginal.
Parents had a Senior 32 with twin 4107s. 10 knots flat out whatever we tried!
I would look at removing as much weight as possible, distributing it to best effect, cleaning the bottom, trying some propellers and perhaps still having to settle for only being able to plane in flat conditions if lucky.
Duncan
<hr width=100% size=1>
miket
Well-Known Member
Re: \"Over the hump\"
Sorry to be negative but ...... "you've got to be joking"!!!!!
Never in a million years will you get close to planing with this boat/ engine configuration.
1. The Osbourne hull is built like a battleship, so heavy.
2. Perkins 4107/ 4108, from memory are about 45 hp.
3. They must be at least 35 years old by now.
The hull will go faster but as indicated on an earlier post you are probably looking at around twice the hp required and then you need to change the outdrive legs which I suspect are the Enfield variety?
<hr width=100% size=1>
Sorry to be negative but ...... "you've got to be joking"!!!!!
Never in a million years will you get close to planing with this boat/ engine configuration.
1. The Osbourne hull is built like a battleship, so heavy.
2. Perkins 4107/ 4108, from memory are about 45 hp.
3. They must be at least 35 years old by now.
The hull will go faster but as indicated on an earlier post you are probably looking at around twice the hp required and then you need to change the outdrive legs which I suspect are the Enfield variety?
<hr width=100% size=1>