Repower Required

Sailor Mikey · Newbie

Repower Required

Stanley · Guru

Welcome to the forum Sailor Mikey.

The Alberg 35 is a wonderful cruising boat but it suffers from the same issues that affect many older traditional sailing boats. She was designed at a time when an auxiliary engine was just there to get you in and out of the harbor. Today everyone wants to be able to motor at hull speed or close to that all the time.

The A35 has a short waterline when motoring but this gets longer when she heels over when sailing, thus she will sail faster than she will motor.
The other issue is that there is a restricted apeture for the propeller and this limits the amount of power that you can get into the water. Please let me know what diameter propeller you fit, then I can run my propeller calculator and work out what will work best. The whole trick to having a successful repower is to tune the engine and transmission ratio and propeller together to get the most efficient combination. Buying more HP and not getting it into the water is just a waste of money.

Stanley

Sailor Mikey · Newbie

Hello Stanley:

Thanks for the prompt reply and welcome. In looking at an old survey, the vessel still has the 3 bladed propeller 14" x 11" RH pitch. The current engine was mounted at a 15 degree angle to a 4" coupler. The transmission is a Hurth HBW100-2R with a 2:1 ratio Fwd and Rev. Technically I think the ratio was 1.86 according to the Hurth specifications.

This engine / transmission / propeller combination seemed fairly optimal except in high current situations at our local ocean access channel where tidal current can occasionally approach 5-6 kts. At those infrequent times, I had to run fairly high RPMs to make much headway against the current.

I look forward to your recommendation and advice regarding the purchase process.

Thanks very much in advance.

Mikey

Stanley · Guru

Hello Mikey,

I suggest the Beta 25 with 2:1 transmission. The propeller calculation comes up with 14"x 9" three blade RH propeller with 50% BAR.
This is the most efficient and buying more HP will not necessarily provide better boat speed. Going up to the Beta 30 actually shows a slightly slower estimated max boat speed as the

Part of the issue is the short waterline and part is the angle of the shaft. The steep angle of the shaft means that a good amount of the power developed by the engine is wasted as the propeller is trying to push the stern out of the water instead of pushing the boat forward. However, you should still just manage about 6.4 Knots wide open. You wont hurt the engine by running it wide open but we will have to put another mark on the dipstick because of the steep angle of install.

Again, I do not publish pricing on the forum as prices change over the years but the forum should stay for reference. Please email me directly for pricing stan@betamarinenc.com

Stan

Sailor Mikey · Newbie

Good Morning Stan:

Thank you for the information and recommendation. The Beta 25 does sound like an excellent replacement for my previous engine, that was pleasant surprise for me, and I look forward to working with you on option details.

How will my 14 x 11 propeller perform in comparison to the optimum calculation propeller of 14 x 9?

What measurements do I need to make to insure that the Beta 25 and TMC40 combination will mate up with my 4 in. prop coupler?

And if there is a height difference, are the engine mounts adjustable, or how can I resolve that issue by shimming? I am hoping not to have to modify the existing engine rails and bedding structure.

I will contact you directly to discuss purchase options.

Again, thanks for your help in this re-power effort.

Mikey

-- Edited by Sailor Mikey on Tuesday 21st of August 2018 12:08:40 PM

-- Edited by Sailor Mikey on Tuesday 21st of August 2018 12:09:24 PM

Stanley · Guru

Your propeller will load the engine too much and stop you reaching the RPM it should. Thus if you can only reach 3,100 in gear then you stand the risk of overheating the engine plus it will only be a 22HP engine as that is the HP that it develops at 3,100.

We include a new shaft coupling with the new engine and transmission. You just need to let us know what diameter your shaft is. However, the TMC40 transmission and the Hurth mechanical transmission both use the same 4" coupling so if your old shaft coupling is in really good condition, you could re-use it.

The flexible mounts are adjustable but I cannot provide any advice on mounting without you providing some basic measurements so that I know what you have. I have some different drawings of the W27 showing different mount arrangements. The most common one shows the engine on 15" centers (port to stbd) with the base of the flex mounts about 1 1/2" above the height of the shaft center. Once you can confirm what you have, I can let you know a bit more.

my1972ih · Member

and a good propeller shop can re-pitch and balance that prop for you.

Sailor Mikey · Newbie

Hello Stan:

Thanks for all the information. My initial measurements show that the previous rear mounts were on 15 1/2" centers, and the W27 had a single front mount. For some reason, the rails are slightly wider in front by about 1/2", so I am hoping they will work without any significant modification. The center of the propeller shaft is 2" below the base of the current mounts, so that is close also, but will require shimming of some sort. I believe my propeller shaft is 1", but I will confirm, and I will definitely pull the prop and get it re-pitched before launch with the new motor.

You are correct, the C panel is way too big for the area where my current panel is located, so the B panel recess with lid will be the choice. My current Westerbeke panel is 9 1/2" X 6" so B panel will fit with minimal cutout changes.

I am sure there will many more questions as we go forward, but wanted to get these to you for planning purposes.

-- Edited by Sailor Mikey on Tuesday 28th of August 2018 12:05:51 PM

-- Edited by Sailor Mikey on Tuesday 28th of August 2018 02:42:17 PM