Propeller size

[Chris G]

Hello Guys.

Does anybody know the correct size of the propeller for an Albin 25 Deluxe, Volvo Penta MD17?
Mine has seen better days and has no stamp on it.

Thanks in advance.

[dkirsop]

16.5" x 12" is the original size and what I have on my boat.

[WillieC]

For the MD3B, which is very close to the 17C, 36hp, same (or close) max revs, the original handbook says 17 dia X 14 pitch. Mine has the 17X13LH, of course, and two or three prop shops agree with the 17X13 configuration.
Extra bonus for you: YOU ARE IN EUROPE WHERE NOBODY WILL GIVE YOU CRAP ORDERING A METRIC PROPELLER!

I went round and round over here and finally decided to order an SAE prop and fit a converting spacer for my metric shaft. The wonderful gentleman at the desk said, well we could get you a metric bore prop but it will take 8 weeks from Michigan Propeller. I about lost my teeth. Now I could have ordered one directly myself but I had too many unknowns so I took the whole kaboodle to the Prop Shop in Mukilteo, shaft, old prop, zinc, cutlass, because the overall distance between the end of my cutlass and the leading edge of the prop is 7" tops. AND, the RB transmission that was used on the MD3B moved the shaft forward about 1/4" when in "FWD". (The MS transmission frequently used on the 17C does not so move.)

I had 8 weeks of other stuff to do and it is not yet boating season for us, so I said let's do it! I will get a shiny new USA prop that they will fit to my shaft and key and shave the front end so it does not impinge on all my critical measurements AND I will get to keep the extra nut that somebody down the line cut threads for IN FRONT of the prop! My built in prop puller!

I also went ahead and ordered a new cutlass bearing from Albinmotor. When it arrived, my heart sank when I picked up the package. It was way too light for a brand new cutlass bearing. I figured somehow, it got shipped without actually getting packed. Or, worse, it got lifted in transit. But all the tape was intact and there was no nasty note from Customs, so it didn't make sense. I got my old bronze cutlass and compared it to the package and there was no way the same bearing was in that box. Do I open it or take pictures or what? Shaking the package indicated that something was in there, so I thought I gave the wrong part number, double checked that, nope. Then I started pushing on the package and found the part and it seemed like it sure could be about the right size so I finally opened it. Here is what I found:

IMG_0727.JPG

I thought it was made of wood! (I have read of composite cutlass bearings, but I have not seen one until now.)
I think it will actually be better than the original, but I was swimming for a while.

Here is the original:

IMG_0728.JPG

Other details: My shaft is 30mm with standard metric taper of 1:10. Bore length of prop is supposed to be 80mm, mine has worn down, eroded to about 77mm. Length of taper on shaft is 75mm. Small hole in prop is about 22mm.
In 75mm of shaft length, the diameter goes from 30mm to 22.5mm, 7.5mm reduction. 7.5:75=1:10. Key is bastardized SAE, custom. Definitely not metric. The thread on the end of the shaft is also SAE, lucky for me!

Long answer. Hope this helps.

(Edit: remember, dkirsop has the AD21 engine, not the MD17C super duper deluxe THREE cylinder engine!)
I also have the newer deluxe hull like yours. 1973 vintage.

[Chris G]

Thank you for the replies guys.

Willie, its great that you take the time to give all the extra info. Who knows, there could be something I have overlooked, so it is great to be able to draw on other Albineers' experience. It's a great help and very interesting too. I appreciate it.

As for the footnote about the Albin 25 and the 25 Deluxe:

I spoke to a guy yesterday, and he says he prefers the original Albin 25, as he can open the bulkhead between the cabin and the doghouse so he can watch TV set in the stem of the cabin from the doghouse...... without using his glasses. These Swedes think of everything

[WillieC]

I am about to open up my bulkhead as well since I need to move my engine forward to accommodate the longer transmission and I may utilize the factory dual pulley that bolts up to the flywheel. All I need now is a Swedish large screen tv!
I mentioned just about all I have dealt with getting my prop replaced. Check all your measurements, since Albin used a couple different shaft sizes and who knows what has been modified on your boat. All those pesky little details are critical and so I went with the "local" highly regarded prop shop. (They are about two hours away on the busy side of the sound.) The Big Boys didn't even want to talk about my metricity, just buy a new shaft, seal, cutlass bearings, coupler, etc... Hey, you're rich, you own a boat, fork it over! My old prop even had the stamp and work number of the original shop in Victoria that supplied it and THEY wouldn't talk to me. The little guy who shows up for work every day and takes care of the myriad runabouts, sailboats, and cruisers in Puget Sound and the lakes and rivers around here really cleared the fog out for me. I willingly pay for his expertise. When these guys croak, heaven help us all.

[denchen]

ChrisG I have a Albin 25 with a BMC 1800 diesel giving 37 hp at 3,500 rpm on a PRM 2.1:1 box and have a 16 by 13 inch 3 blade prop that goes a treat. I`m usually offshore, North Nolfolk, East Lincolnshire so not far from you.

[Chris G]

Hi Denchen,

Thanks for that. Yes, I'm just a stone's throw away, on the other side of the North Sea. Although I have family in Manchester, UK. I was over there last month. Probably flew over your boat

[OldDemps]

Need the recommendations and your math on new propeller for my 1975 A25 DeLuxe w 39hp at 3000 rpm. Transmission is 2.36. What other info is needed?

Prior 36hp MD3B Volvo prop was 17x14 per survey (not personally verified)

Yard now is estimating new prop 17x16 w 39hp.

I would think a high pitch prop like 16” would be too fast bumping it around the dock and running at low RPM’s.

your thoughts?

Thanks

[WillieC]

A good prop shop can easily run the numbers for you as a cross check on the local yard.
I found two that agreed, and doh!, same as the prop that was on there originally.
Somebody else on here has the same set up as you, IIRC. If I run across it, I will cite it.

There are also online calculators, but they may ask questions that need clarification.

[OldDemps]

Thanks WillieC
Yes my concern is prop shop / yards don’t understand our “semi displacement” A25 40 yr old hull characteristics.

[WillieC]

I need to get over to Seattle and see your progress! I think you will have a nice boat when running. Then take your time with the rest of it.

[Beta Don]

Yard now is estimating new prop 17x16 w 39hp.

I would think a high pitch prop like 16” would be too fast bumping it around the dock and running at low RPM’s.

your thoughts?

You would never select a prop based on how it performs 'bumping it around the dock' so I would put those concerns aside

You want a diameter and pitch which will allow the engine to reach it's rated RPM but just barely running on flat water - That gives you the best fuel economy. If you're 'overpropped' (too large diameter or too much pitch) you can't reach the rated HP peak for your engine, so in effect, you have a less powerful engine than what is installed. If you're 'underpropped' you reach rated RPM easily and have throttle and horsepower left over which you can't use

A 17 X 16 sounds a bit too much compared to what others are using. If it was my boat, I think I would buy a 17 X 14 and then you have the relatively inexpensive option of having your new prop stamped up or down an inch (to a 17 X 13 or 17 X 15) if needed to fine tune it and get things just right

After my 100 HP Yanmar install in my A27, I was in an unfamiliar place choosing a prop. The original 15 X 13 that came with my 4D61 was obviously not going to be even close. I got REALLY lucky and found someone on eBay selling a brand new 17 inch 3 blade Michigan Wheel prop as a 'marine decorative piece' with a starting bid of $75 . . . . and since nobody but me bid on it, I got a $450 prop for $75. It was only a 10 inch pitch, but my prop shop restamped it to a 14 pitch for me for $200 and that turned out to be perfect - Lucky guess on my part as I had 'experts' telling me I needed everything from 16 to 12, so I went with my own computations

A good shop will carefully measure your new prop and tell you how close it is to what the manufacturer claims. Frequently, the 3 blades are not exactly the same pitch when it leaves the factory - Hard to believe, but often true - But after you have it reworked, they will be, so fine tuning a prop can be a wise investment and get you exactly the correct pitch for your boat and the best performance for your fuel dollar

Don

[Chris G]

IMG_1788.JPG

Well guys, finally got round to it!

[WillieC]

New shiny stuff! I love it! That box looks very similar to mine (I went with 13 pitch.) It feels like it weighs about half the old prop, which is about 25 years older. Keep a good eye on your zincs.

[DesertAlbin736]

For what it's worth, my prop is 16X12 RH for the 24 HP Yanmar. Previous owners passed along a spare 17X13 RH prop, which is likely not the original prop for an AD21 or Volvo engine because that would have been left hand. So I wonder if one of the owners previous to the folks we bought from had tried the 13 pitch prop & for one reason or another decided to switch to a slightly smaller, flatter pitch prop?

Generally speaking I run at a max cruising RPM of 2,350 (which may not be the full max RPM for the engine) for a cruising speed of 6.5 knots on flat, no-current water.

PS, one of my dreams, and I don't know if we'll ever get to do it, would be to rent an Albin 25 for a week to cruise the Gota canal in Sweden.