Quiet motoring?

[Cy Fraser]

Looking at buying Cat 30, engine starts easily, seems to run well but can't imagine being below for more than 5 min underway. Any other 80's production boats ( engines ) with quieter rides ?

[FSMike]

I don't remember Catalina 30s being that noisy, may be a problem with that particular boat. An engine survey should turn up any mechanical problems, also might need new or additional engine compartment insulation/soundproofing.

Most 30-odd year old boats aren't going to be as quiet as new lol.

[FamilyVan]

This might be a silly question, but were you observing the engine volume with any panels off or the engine compartment open? I think the sound insulation will be the biggest contributing factor to noise below.

I can't imagine whatever is in an 80's Cat 30 is any louder than my Perkins 4.108, which is perfectly tolerable closed up, but very noisy open.

Sent from my XP7700 using Cruisers Sailing Forum mobile app

[markpierce]

Cy, is your boat significantly noisier than other boats under power? What were the characteristics of quieter boats?

[jeepbluetj]

My boat is pretty loud under power. It's not horrible, and you can have a conversation in the cockpit, but it's loud enough below to require raised voices. It's definitely loud enough that it's a joy to turn it off to sail.

I have the A4, which is actually quieter and smoother than the small diesels used by Catalina in the early 80's. They got much better as time went on. The engine noise in the cockpit is around the noise level of the blower that's mounted in the coaming. A4 == run the blower all the time, so that adds to the noise level.

I have zero soundproofing other than the liner and the cushion on the settee. Methinks soundproofing would help a bit, although the front of the engine (the flywheel for the A4) is too close to soundproof that front part.

I think one of the problems with noise in a C-30 is the engine is pretty much in the middle of the boat (under the galley counter and the dinette settee) - Not in the back where there's less area to radiate sound.

If you look at other boats of the era, they're all noisier than modern boats. But I'd say the 30 is a bit noisier because of where the engine is located.

[hugosalt]

My Yanmar 3GM with SD20 saildrive on my 30 fter is still extremely quiet after 30 years.
There are no vibrations from a shaft. Saildrive with 2 heavy duty rubber gaskets make for quiet motoring. Also saildrive allows motor to be installed aft of queen size bunk under
companionway ladder, again making cabin reasonably quiet compared to conventional install. Yanmar still makes same sd20 saildrive. Boat is 1985 30' Lancer mkV.

[GordMay]

Greetings and welcome aboard the CF, Cy.

[a64pilot]

A Diesel by it's nature is a noisy beast, especially the older Direct Injection design.
Having said that improper injection pump timing and or especially dirty injectors can add appreciably to the "rattle" a Diesel makes, but it's going to be noisy, much more so than say in a power boat. May be engine position or maybe it's the engine is though of as auxiliary propulsion.
Have you been in other sailboats under power?
If you buy her, I'd pull the injectors and have them cleaned / tested, mine are in the shop right now, two were good, two were "peeing" meaning no spray pattern, just a steady stream of fuel. I think dirty / bad injectors are not uncommon, especially on a 20+ yr old engine.

[HappyMdRSailor]

Just by nature of the location and enclosure....

Something like this page will help quiet things to tolerable...

http://www.defender.com/category.jsp...311&id=2349105

[Orion Jim]

When it's a little noisy you have a chance to hear a little problem before it becomes a big problem. Kind of like kids. If you can't hear them you're in big trouble.

[UNCIVILIZED]

If you're truly interested in making her quiet, there are a few good articles in the archives of Professional Boabuilder

To super-abridge said articles:
- Make the engine enclosure air tight, all but for it's (sound insulated) air intake & exhaust plumbing. That which feeds the engine the O2 which it needs to breath, in addition to cooling it. Plus that which removes it's waste heat.
- Sound insulate the crap out of the engine enclosure.
- Use sound isolating mounts on anything of significance. Including the enclosure it's self.

IIRC, the top item alone will cut down on your engine noise by over 50%. Albeit it does necessitate some brain work, on designing your engine's enclosure. But then, as Robert Heinlein always said, TANSTAAFL.

[Kenomac]

Some boats are just louder than other boats, and some people just seem more sensitive to the diesel racket. Our Hunter was quite a bit louder than our present boat, but I don't remember being particularly bothered by the noise. It just depends on the amount of sound proofing in the engine compartment.