Time to churn up the archives
Larry,
Click on the word "Search " and enter something like ' M25 prop pitch ' or similar. I did and found quite a few threads pertaining to your model Ericson and prop pitch discussions.
If you have questions about this you can drop me a note directly.
Best,
Loren
(sailaway10 at comcast dot net)
Larry,
Click on the word "Search " and enter something like ' M25 prop pitch ' or similar. I did and found quite a few threads pertaining to your model Ericson and prop pitch discussions.
If you have questions about this you can drop me a note directly.
Best,
Loren
(sailaway10 at comcast dot net)
Mort Fligelman
Member III
E35-3 Prop Specs
I inquired Martec for this information....unfortunatly those specs and correspondence are at my winter home.....I got my Martec folder, and it is excellent.....works beautifully....I have had Martec Folders on my three previous boats dating back to 1971.....I swear by them.....they perform as well as any solid, and you are not dragging a bucket every time you turn off the engine......you can go to the Martec web site and get the proper information
I inquired Martec for this information....unfortunatly those specs and correspondence are at my winter home.....I got my Martec folder, and it is excellent.....works beautifully....I have had Martec Folders on my three previous boats dating back to 1971.....I swear by them.....they perform as well as any solid, and you are not dragging a bucket every time you turn off the engine......you can go to the Martec web site and get the proper information
MarineCityBrian
Apprentice Tinkerer
Old thread, but info may be useful
Mort - per chance did you ever grab the specs for your Martec folding prop? I know this thread is now 10 years old, but it would be highly valuable info that I hadn't found readily searching for "E35-3 Martec", including our excluding the search term "pitch". The prop on my E35-3 is a fixed Michigan Sailor 15" x 9" pitch x 1" shaft. I'd assume you'd want the same diameter in Martec, but I'd also assume you might be able to be a bit more aggressive on the pitch to get a little more boatspeed. Just curious what yours might be as Martecs are readily available on the used market.
Mort - per chance did you ever grab the specs for your Martec folding prop? I know this thread is now 10 years old, but it would be highly valuable info that I hadn't found readily searching for "E35-3 Martec", including our excluding the search term "pitch". The prop on my E35-3 is a fixed Michigan Sailor 15" x 9" pitch x 1" shaft. I'd assume you'd want the same diameter in Martec, but I'd also assume you might be able to be a bit more aggressive on the pitch to get a little more boatspeed. Just curious what yours might be as Martecs are readily available on the used market.
Kevin A Wright
Member III
I just changed out the original 2 blade prop on my E35-3 (with M25) for a 3 blade 15 RH 11 bronze prop (1" shaft). Still have the original 2 blade if you are interested. Didn't pick up much performance with the 2 blade but I do back better now.
Kevin Wright
E35 Hydro Therapy
Kevin Wright
E35 Hydro Therapy
MarineCityBrian
Apprentice Tinkerer
Let's start a prop database!
Kevin - Thanks for the note, and sincere apologies for my delayed response. I've still got the original 2-blade 15" x 9"P x 1" Tapered shaft RH rotation prop on the boat, which is still in fine shape. What I am hoping to garner here is a discussion about various blade combinations (2, 3, 4-blade, etc), prop types (fixed, folding, feathering, etc), and prop pitches and diameters to gain data points on what people have used and what works well for particular conditions. In the great lakes you can find yourself both fighting high winds and significant current, so "overpropping" is somewhat needed.
I, too, also just bought a 3-blade 15" x 11"P RH to give a try (it was a great deal), so I'm really curious as to how yours is working for you. Per your comments you mention that you didn't pick up much performance (is that referring to speed under motor?) but that you do back better now (would that refer to less prop walk to port under reverse?). I'm also curious - did you have any difficulty bringing the engine up to max RPM?
For any others who may read this I'd be very curious to understand what prop (especially if it's a folding or feathering variety) you may have and the conditions in your area (windy, currents, tidal currents, etc) which led you to your decision. I'd be happy to create a matrix of props, engines, vessels, etc, to help the community pick a prop. As I mentioned in my previous post there are quite a few available on the used market for reasonable prices these days (especially Martec folding props, which at one time were the gold standard) and having such a resource would avoid the trial and error method and wasting the manufacturer's time when you may not be buying a product new from them.
Happy sailing (and motoring!).
Kevin - Thanks for the note, and sincere apologies for my delayed response. I've still got the original 2-blade 15" x 9"P x 1" Tapered shaft RH rotation prop on the boat, which is still in fine shape. What I am hoping to garner here is a discussion about various blade combinations (2, 3, 4-blade, etc), prop types (fixed, folding, feathering, etc), and prop pitches and diameters to gain data points on what people have used and what works well for particular conditions. In the great lakes you can find yourself both fighting high winds and significant current, so "overpropping" is somewhat needed.
I, too, also just bought a 3-blade 15" x 11"P RH to give a try (it was a great deal), so I'm really curious as to how yours is working for you. Per your comments you mention that you didn't pick up much performance (is that referring to speed under motor?) but that you do back better now (would that refer to less prop walk to port under reverse?). I'm also curious - did you have any difficulty bringing the engine up to max RPM?
For any others who may read this I'd be very curious to understand what prop (especially if it's a folding or feathering variety) you may have and the conditions in your area (windy, currents, tidal currents, etc) which led you to your decision. I'd be happy to create a matrix of props, engines, vessels, etc, to help the community pick a prop. As I mentioned in my previous post there are quite a few available on the used market for reasonable prices these days (especially Martec folding props, which at one time were the gold standard) and having such a resource would avoid the trial and error method and wasting the manufacturer's time when you may not be buying a product new from them.
Happy sailing (and motoring!).
Kevin A Wright
Member III
I may have picked up half a knot in speed under power, but some of that may be coming from a clean hull as well. No problems getting up to max rpm with the 3 blade. The backing improvement may be slightly less prop walk, but a very noticeable improvement in 'bite' on the water. With the 2 blade there was a very noticeable lag between increasing the rpms and a change in speed or direction. That lag time is much reduced now, which is nice when maneuvering in a close marina.
Kevin Wright
E35 Hydro Therapy
Kevin Wright
E35 Hydro Therapy
MarineCityBrian
Apprentice Tinkerer
Nice! I'll report my findings as well next season when I install the new (to me) prop (same specs as yours, but potentially a different blade profile, etc). I find many of the same issues you have with the present 2-blade (sluggish in reverse, less "bite" in either direction, etc). Any idea what pitch your old 2-blade is?
Any noticeable decrease in speed under sail? Also, do you lock your trans in reverse while sailing? The Hurth trans manual for my tranny says it's no issue whatsoever to leave it in neutral and let it spin (theoretically reducing drag a bit) but the old adage was to put it in reverse.
Any noticeable decrease in speed under sail? Also, do you lock your trans in reverse while sailing? The Hurth trans manual for my tranny says it's no issue whatsoever to leave it in neutral and let it spin (theoretically reducing drag a bit) but the old adage was to put it in reverse.
MarineCityBrian
Apprentice Tinkerer
The 5424 (AKA "M-30) is the heavier, larger-displacement big brother to the M-25. Per the spec sheet in the manual available on this site, it makes 24 HP compared to the M25's 21 HP, so you're up a bit on power and probably even more on torque given the larger engine displacement. It also makes max power at 2800 RPM compared with the M-25's 3200, so you'd need to pitch your prop accordingly. Likewise you'd need to pay attention to the fixed gear ratio in your trans - we may have similar prop speeds in the end if they reduced your ratio as compared with mine.
As mentioned above my original is a 2-blade fixed 15" dia x 9" pitch, and it's painfully slow going into the wind, and even more painful against a current. Since we wanted to do some river cruising (the current under the Blue Water Bridge in Port Huron is swift enough to be able to see eddys in the water...) next season I'm going to give a 3-blade 15" dia x 11" pitch.
As for recommendations on folding props my father had great success with a Martec "Eliptec" 2-blade folding that he purchased for his C27 shortly after he bought it (it's an '83 so roughly '84 or '85) and Martec specifically "put a little more twist in it" for him (the manufacturer recommended he increase the pitch) and he's been quite happy with additional motoring speed and limited drag. He's also quite proficient using it in reverse, but he's also had plenty of practice. That props' been on the boat ever since and is still working great.
I'd love to hear from more Martec folding owners to get their feedback on prop sizing. Again - these props are going for very reasonable rates on eBay (1/10th to 1/20th the price of a new MaxProp feathering) so it would be a great performance value.
As mentioned above my original is a 2-blade fixed 15" dia x 9" pitch, and it's painfully slow going into the wind, and even more painful against a current. Since we wanted to do some river cruising (the current under the Blue Water Bridge in Port Huron is swift enough to be able to see eddys in the water...) next season I'm going to give a 3-blade 15" dia x 11" pitch.
As for recommendations on folding props my father had great success with a Martec "Eliptec" 2-blade folding that he purchased for his C27 shortly after he bought it (it's an '83 so roughly '84 or '85) and Martec specifically "put a little more twist in it" for him (the manufacturer recommended he increase the pitch) and he's been quite happy with additional motoring speed and limited drag. He's also quite proficient using it in reverse, but he's also had plenty of practice. That props' been on the boat ever since and is still working great.
I'd love to hear from more Martec folding owners to get their feedback on prop sizing. Again - these props are going for very reasonable rates on eBay (1/10th to 1/20th the price of a new MaxProp feathering) so it would be a great performance value.
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Kevin A Wright
Member III
Haven't noticed any decrease in speed under sail with the 3 blade, but logic says there must be a touch. Yes I lock into reverse when under sail. I've always understood that creates less drag than a rotating prop (think of a helicopter autorotating down vs what happens when the rotors seize).
Kevin Wright
E35 Hydro Therapy
Kevin Wright
E35 Hydro Therapy
Also much nicer for your transmission...
MarineCityBrian
Apprentice Tinkerer
There's certainly debate on the topic, but specific to a boat, in an incompressible fluid such as water, with a much higher blade area than a helicopter, this study says otherwise:
http://www.sailnet.com/forums/gear-...ee-wheeling-prop-test-data.html#/topics/53628
Though I do get the helicopter scenario, the vastly smaller blade area in comparison might make a profound difference s does water as the fluid.
So far as being kind to the transmission I get the logic there as well, but the ZF 5M manual specifically states:
”3.5 Sailing or moving in tow
Rotation of the propeller while the boat
is sailing, being towed, or anchored in a
river, as well as operation of the engine
with the propeller stopped (for charging
the battery), will have no detrimental ef-
fects on the gearbox.
IMPORTANT
When the boat is sailing (engine
stopped), the gear lever must be in zero
pos-ition. Never put the gear lever in the
pos-ition corresponding to the direction
of travel of the boat.
Locking the propeller shaft by an addit-
ional brake is not required: use the gear
lever position opposite your direction of
travel for this purpose.”
All of that said, certain transmissions DO suffer damage when rotated by an external source (other than the engine). In the automotive world anyway some transmissions are lubricated by a pump connected to the input shaft of the transmission, which would not turn if the vehicle were to be put in neutral and pushed or towed, and could ruin the trans. I wouldn't see why certain Marine gearboxes wouldn't operate under the same principle, but inferring from the ZF manual the 5M isn't one of them. Though meshing of the gears even under little to no load could wear them out more than not rotating them at all. I am also aware of other Marine transmissions that specifically say to lock the prop by putting it on reverse while under sail. And one would certainly want to lock a 2-blade folding prop sideways to keep gravity from pulling one of the blades down.
All just food for thought.
http://www.sailnet.com/forums/gear-...ee-wheeling-prop-test-data.html#/topics/53628
Though I do get the helicopter scenario, the vastly smaller blade area in comparison might make a profound difference s does water as the fluid.
So far as being kind to the transmission I get the logic there as well, but the ZF 5M manual specifically states:
”3.5 Sailing or moving in tow
Rotation of the propeller while the boat
is sailing, being towed, or anchored in a
river, as well as operation of the engine
with the propeller stopped (for charging
the battery), will have no detrimental ef-
fects on the gearbox.
IMPORTANT
When the boat is sailing (engine
stopped), the gear lever must be in zero
pos-ition. Never put the gear lever in the
pos-ition corresponding to the direction
of travel of the boat.
Locking the propeller shaft by an addit-
ional brake is not required: use the gear
lever position opposite your direction of
travel for this purpose.”
All of that said, certain transmissions DO suffer damage when rotated by an external source (other than the engine). In the automotive world anyway some transmissions are lubricated by a pump connected to the input shaft of the transmission, which would not turn if the vehicle were to be put in neutral and pushed or towed, and could ruin the trans. I wouldn't see why certain Marine gearboxes wouldn't operate under the same principle, but inferring from the ZF manual the 5M isn't one of them. Though meshing of the gears even under little to no load could wear them out more than not rotating them at all. I am also aware of other Marine transmissions that specifically say to lock the prop by putting it on reverse while under sail. And one would certainly want to lock a 2-blade folding prop sideways to keep gravity from pulling one of the blades down.
All just food for thought.
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