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bvermeer 11-30-2012 03:15 PM

Beta 20 with Sea Prop 60 Saildrive
Hello all
Last spring I installed a Beta Marine 20 (Kabota 722 engine) with a Sea Prop 60 saildrive unit in my 1978 Islander Bahama 30, replacing the well used Volvo MD7A. I did the installation myself with the main goal of reducing engine noise and vibration (hence the saildrive configuration). I went so far as to replace the muffler with a Centek Vernalift muffler along with a Centek Water Separator, usually used in a generator application. The engine compartment was totally isolated and insulated, again to reduce the noise. I now have just over 100 hrs on the Beta and the engine/saildrive unit is performing as expected. The noise of the smooth running three cylinder engine is so low at idle that I can't tell if the engine is running or not when I'm up at the bow. However, and there always seems to be a "however", the Sea Prop 60 saildrive unit makes more noise in gear at idle than the engine! There is a very clear "ticking" noise when the transmission is put in gear, a noise that disappears above 1500 rpm. The noise sounds like a baseball card in the spokes of a bike wheel. It is annoying!The Canadian distributor for Beta (who happens to be local) believes it to be gear lash when the transmission is under minimal load. I have contacted the distributor for the Technodrive Twin Disc Sea Prop 60 and they do not have an answer, claiming that the noise is "normal". Although not a "mechanic", I am somewhat mechanically inclined and suspect that this much noise out of a gear drive cannot be "normal". Gears should mesh silently, certainly not louder than a running diesel! Sea Prop does not provide a schematic of the internal parts of the saildrive unit and, without taking it apart, I am unable to determine the source of this noise. Has anyone had any experience this the Sea Prop unit? Is this a common noise, usually masked by the diesel? Although I am certainly satisfied by the overall unit, I am disappointed that the transmission is making more noise than the engine!

Bert Vermeer
Sidney BC

Meriachee 01-08-2014 02:55 PM

Re: Beta 20 with Sea Prop 60 Saildrive

I read the GOB article. Nice install.

Did you ask around if there's another SeaProp60 within a decent distance that you might actually listen to? That would pretty much tell you if it's common or yours, and dictate a course of action.


bvermeer 01-08-2014 03:24 PM

Re: Beta 20 with Sea Prop 60 Saildrive
Thanks for the comment Gary. Yes, I've listened to another SeaProp and found the noise to be much less than my installation. Interestingly enough, that particular unit had a different gear ratio. Beta Canada has stepped up to the plate since my last posting. They have supplied a softer drive plate between the engine and transmission. That installation has reduced the RPM the noise is heard at from 1500 to about 1200. But the noise is still there. So Beta (England) has sent me a brand new leg with the different gear ratio in the hope that the volume of noise is particular to my current leg. Unfortunately, they sent the wrong prop and I am currently waiting for the correct prop before doing the replacement installation. The new leg is currently in my tool room, ready to go. I find it heartening that Beta (England) and Beta Canada have both pursued this issue with me in the hopes of finding a solution. I will post the results when the installation is completed.

Bert Vermeer
s/v Natasha
Sidney, BC

CalebD 01-08-2014 11:55 PM

Re: Beta 20 with Sea Prop 60 Saildrive
Why would a saildrive unit be any quieter than a direct drive prop shaft & prop?
Lots of extra complexity with a saildrive too.

bvermeer 01-09-2014 12:32 AM

Re: Beta 20 with Sea Prop 60 Saildrive
Obviously the engine is going to make the same amount of noise connected to a direct shaft as it will with a saildrive unit. However, noise is caused by vibration and a considerable amount of noise on board a small boat is the engine vibrating the hull, cabinetry and everything attached to it. Not much can be done about the amount of noise the engine makes. But much can be done about the associated vibration.

Softer motor mounts are the most efficient way of isolating engine vibration from the boat. However, with the precise alignment required with a direct shaft-to-prop setup, soft mounts would allow the engine too much movement. The cutlass bearing and stuffing box would suffer. I was contemplating a system called Aquadrive, basically a thrust bearing system that allows the engine to be mounted independent of the shaft. This would allow for the softer mounts without effecting the shaft. Unfortunately, in my application, there just wasn't enough room between the transmission and stuffing box to mount such a system. The only real option I had (to attain my goal of reducing vibration caused noise) was the saildrive. With the engine mounted directly to the saildrive unit the entire assembly could be mounted on very soft mounts, reducing the transmission of vibration to the hull. I can wiggle the engine/saildrive unit considerably by hand. The intense vibration of a diesel at speed is not felt through the cockpit floor as is common on many small boats. The rattling of stuff inside the boat is minimal.

Having had a few small boats over the years (everything from outboards to Atomic IVs to Volvo diesels) I would say the system I have in place is probably the quietest yet. It helps to insulate the engine room as well.

Yes, the saildrive has it's complexity and some concern about corrosion. However, having taken the appropriate precautions I have observed absolutely no sign of any corrosion after two years afloat.

Bert Vermeer
s/v Natasha
Sidney, BC

bvermeer 03-15-2014 09:19 PM

Re: Beta 20 with Sea Prop 60 Saildrive
I think the transmission noise saga has finally come to a successful conclusion. Beta (and Beta Canada) stepped up to the plate and supplied a replacement Sea Prop 60 with a lower gear ratio and larger folding prop. I did the installation last weekend and once back into the water, there is no transmission noise! With the different set-up I'm also getting a half knot of extra speed at the same RPMs. It's taken a while but better late than never. Now I'm completely satisfied with the Beta 20 - Sea Prop saildrive setup, a quiet, dependable system with minimal vibration. Time to go sailing!

Faster 03-15-2014 10:03 PM

Re: Beta 20 with Sea Prop 60 Saildrive
Good to hear, Bert.. will keep an eye out for you this summer!

Bertie chapman 02-22-2015 11:26 AM

Re: Beta 20 with Sea Prop 60 Saildrive
Hi we have recently crossed the atlantic on a yacht, we are fitted with two nanni 30's and seaprop 60's. We had exactly the same problem with one of the motors. We had the same noise but it progresivly got worse, it actually came from bellhousing area. We then established that the bolts securing the bellhousing adater plate had come undone three unscrewed completely and 5 unscrewed and sheered off by the fly wheel. Now we established water in the saildrive and are battling getting information. The noise you experiencedl we dis, almost like washers in a tinned can.

bvermeer 02-22-2015 12:57 PM

Re: Beta 20 with Sea Prop 60 Saildrive
Yikes!! That sounds far more serious than the ticking noise that we encountered. I now have just over 100 hours on the replacement Sea Prop 60 saildrive unit and am still pleased with it's performance. If I listen carefully I can still hear a ticking noise from the gear lash of the transmission, but nowhere near as loud and annoying as the original unit. I have to write that off as a gearbox that wasn't aligned quite right from the factory. Apparently, there is no adjustment available in the gearbox. What you describe, "washers in a tin can", sounds far more random than the very steady ticking that I was hearing. Good luck with the repair!

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