Cruise speed of early 80's 27's

[Don from Mystic]

I purchased an '83 27A in November and motored it home (an 11 hr trip). The seller had no manuals or other info on the boat and told me he cruised @ 2600/7-8K. I have since aquired an engine owners manual for the 4d 61 (which I will attempt to scan/post at some point, lots of good stuff) which states this motor can turn @ 4K plus. I have also purchased an orig 83 Abin, periodical advertisement on ebay which states the boat does 10-14Kts (Im presuming the Lehman was the only engine choice in 83).

The Yahoo group has a speed data base, but no one seems to run the engine at even near rated RPM. The engine I have has just over 1000 hrs and was obviously well cared for, runs/sounds tight.

Im presuming most of these vessels are on their 2nd 3rd or 4th generation of owners.
Im hoping that theres an "old salt" out there that remembers the boats introduction and can comment if, when new, the boat did the 10-14 the ad claimed.
Don

[Veebyes2]

I had a 100hp Westerbeke in my 1986 27AC. Don't think it EVER saw 14kts unless it was on a trailer.

Top speed with the 100hp was more like 13kts with a clean bottom & lightly loaded.

Maybe 10 or 11kts on a good day with the Ford, JMO.

[jcollins]

(which I will attempt to scan/post at some point, lots of good stuff)

Looking forward to that. I would love to add it to our library.
Please email to jcollins@albinowners.net

Thanks!

[rt11002003]

My 1987 Albin 27 Aft Cabin has the Yanmar engine. According to the manual and the engine data plate max torque and max HP RPM are in excess of 3,000. 3,200 (70HP) and 3,500 (77HP) RPM I think.

About two weeks ago I had the boat out for a couple of hours. At 2,200 RPM the brand new GPS (Garmin 3210c) read 7.25 knots. We had a clean bottom, a full load of fuel, two full sized males (at 215 I may be oversized ) and the usual amount of stuff on board: TV, microwave, extra cooler, two AC units, three electric heaters and etc.

As I've mentioned previously I've seen 10+ knots surfing a wave from a barge and its tug. And that was at a crusing RPM, between 2,200 and 2,600. That was measured by an older hand held Garmin unit.

I'm not sure of the accuracy of the tach on these boats, or any other for that matter.

I've noticed that we don't get huge speed increases with RPM increases as we approach WOT. I think WOT yields about 8.5 knots. Will check it out the next time I run the boat and let you know.

Gene

[Don from Mystic]

The performance curves graph in the origional Lehman manual shows the output of the 4D61 (marinized Peugeot auto engine) @ roughly 40 BHP/2500 RPM BUT 60 BHP/4K. I know my motor will turn this (by accident), but presumed I had too flat a wheel. I know she's no "Rocket" but I have a feeling my cruise speed will really improve if Im closer to 4K. I will know in a month or so. If a piston lands in your backyard, mail it back to me.......

[Chaz]

Welcome to the club!
I too have an 84' 27AC with the Lehman 4D61. Turning 2,500 she'll edge towards 8kts and run at 170degrees, WOT is 3,000rpm where she'll nudge 9kts, but temp edges towards 200degrees. Tried a larger prop with more pitch last season which over-tourqued the engine, brought her WOT down to 2,400rpm and max speed to 6kts and overheated the engine. Switched back to the original prop that the "old salt" prior owner clearly had fully researched and have concluded that I indeed own a TRAWLER, and switched my focus from Max speed to minimal fuel consumption. "Happpiness is the journey, not the destination".

[Mariner]

All boats that do not plane (whether they be displacement hull, or planing hull with insufficient power to achieve a plane) will face a curve of diminshing return as they reach into the higher RPM's. The engine may well be fully capable of 4,000+ RPM, but that doesn't mean that it is by any means efficient or prudent to cruise at that speed.

I am not familiar with the boat or engine, but it would be wise to start collecting fuel consumption numbers as soon as possible to ascertain what kind of efficiency you get at different speeds.

[RobS]

"Happpiness is the journey, not the destination".

I like that - sums it up nicely. Even though I cruise my 28TE doing an economical 16-17 knots that quote still often applies when speaking to those doing considerable more....

[Don from Mystic]

I did the origional post and thought I would do a followup as I have logged well over 100hrs so far this season with no problems. If I have a destination in mind, and not just out for a scenic "putt" I have routinely run this boat at 3200 for as much as two hrs with no problems overheating (stays around 180). Depending on tide its an avg 9++ cruise via GPS. I see my temp rise to near 200 @ over 3500 and have not kept her there long. I have a factory pitch 3 blade non trick prop, likely the origional . The boat is relatively EMPTY, clean bottom and prop. This Peugeot was made to turn 4K and with the correct prop does it effortlessly. Chaz, you may need to "burp" your engine (as some car engines need). See my recent post about bleed fittings. Regards, Don

[jcollins]

"Happpiness is the journey, not the destination".

I like that - sums it up nicely. Even though I cruise my 28TE doing an economical 16-17 knots that quote still often applies when speaking to those doing considerable more....

That's about my cruise too. I "ramped it up" to 20 last weekend and others were still passing me. My 28 is very happy at 17-18. Then we took a envy cruise of Seneca Creek at 6. Very relaxing.

[rt11002003]

Since my last post on this subject I've paid more attention to boat speed vs engine rpm. Using a Garmin 3210c GPS to measure speed, the vessel consistently runs in the 7 knot range at 2300 rpm (depends on wind velocity and direction). It will run up to 8.5 knots at 2800 rpm(again, depending on wind velocity and direction). It gains most of the additional knot and a half by 2600 rpm, from there the vessel is mostly pushing water. Above 2800 rpm doesn't seem to give any more speed.

The engine is a 77 HP Yanmar (at MAX rpm, around 3500) with operating HP of 70 around 3200 rpm.

I've seen 10 knots when surfing off big waves.

I agree with what I hear from most people in this group. If the vessel doesn't plane, one wastes fuel and endures more noise when trying to run close to max rpm and I think I hear the same message from the planing boat owners. My A27AC seems to strike a happy medium from 2300 to 2600 rpm.

[Don from Mystic]

Certainly, there is a "sweet spot" for every combination of hull design / prop / available power.My Oct Natl Fisherman Magazine has an article on 900 HP, (full) displacement hull 30' "Lobster" boats pushing 60 MPH! Each extra knot desired requires a less proportainate amount (much much more) of extra horsepower. On my boat this rpm vs. kts graph seems to go seperate ways just over 3KRPM. Unfortunately, I do not have a "flow-scan" to precisely monitor and chart fuel consumption, but overall its been just over a gallon/hr.

[Dave]

I have always been curious about this myself. When I purchased my Albin 27 it didn't have any info as to the speed or RPM's. I have the Isuzu 160 HP which I normally cruise around 1800 RPM and this gives me about 7 knots according to my chartplotter. I will run as high as 2200 RPM which gives me about 9 knots but the engine is twenty years old so why push it. I find over 2300 RPM it starts to smoke a bit which makes me nervous and the extra speed is minimal. I recently met someone else with the same engine and he also runs at a max of 2200 RPM. I didn't buy my Albin for the speed but rather for the reliability and fuel savings.
It's a great boat!

[Fortunate]

I too have the 4D61 and have the same results as many who have posted in this thread, maintaining 6.5-8 knts (depending on wind, tide, current, etc.) @ 2300-2500 RPM. I have wound her up a few times and have not seen anything over 10 knts in open water with no/ little tide influence.

Just remember .75 gal/ hr.............................

[stardust-v42]

I noticed Dave's mention of "smoke" after exceeding 2300 RPM with the Isuzu engine. I also have seen this smoke begining at 2400-2500 RPM and it gets very noticable at WOT of 2800-3000 RPM. I've looked at the reasons for "white" smoke and I am of the belief that this is unburned, atomized fuel. Do you Isuzu owners think this is correct? I don't think it is water vapor as there is no decrease in my fresh water cooling system.

I tend to cruise at 1900-2000 RPM and maintain 8 kts. At WOT of 3000 RPM the max speed is about 14.2 KTS--FYI