380: Repowering my 2002 Lagoon 380

[CaptRDJR]

I am looking at re-powering my 2002 Lagoon 380. Does anyone have experience upgrading the engines to 39/40HP. I do most of my sailing on the Chesapeake and wouldn't mind some extra power.

Thank you in advance for any help you can provide.

[Cheechako]

I considered putting bigger in my old Lagoon 42. Never did though. One consideration is selecting engines that you can run at lower rpm. I hated the Yanmars at their recommended rpm... sounded like a damn airplane!

[jbinbi]

Not sure what is needed. I had a bene 37 , and at 14k lbs, it had the 3ym30 as the upgraded engine. My 380 doesn't weigh much more (no keel;-) and it has 2 of those! HP/wt ratio is pretty high. They offer the 20hp standard, the 3ym30 has 30 hp, not sure if a need to go to 40hp?

[Cheechako]

Compare engines at the same rpm from their power curves. Some engines are rated HP at very high rpm and sold as lightweight. They are really small engines overrated. An interesting discussion is that commercial diesels are often rated at different HP for different uses.... on the same engine. So a 400 HP engine for light duty rec use may be rated as a 300 hp engine for 24/7 commercial use. Why? Because engines last longer at lower rpm.

[gspeak]

Originally Posted by CaptRDJR

I am looking at re-powering my 2002 Lagoon 380. Does anyone have experience upgrading the engines to 39/40HP. I do most of my sailing on the Chesapeake and wouldn't mind some extra power.



Thank you in advance for any help you can provide.

Why? Are your motors needing replacement? What size are they & how many hours have they done? What sort of speed are you wanting?

Dave

[tuskie]

Originally Posted by gspeak

Why? Are your motors needing replacement? What size are they & how many hours have they done? What sort of speed are you wanting?

Dave

Dave has a good point. Sailing cats have much different hull design to power cats. Adding extra power often just makes the sterns squat down, burning extra fuel and not going much faster.
Ideal engines will be operating a peak torque revs whilst delivering hull cruising speed.

[CaptRDJR]

Thanks for the feedback.

GSPEAKE,
To answer your question. I do most of my sailing on the Chesapeake Bay which is fairly shallow and can easily generate a 3+ foot chop in 15 to 20 kts of wind. My Volvo diesels are 28HP each and have about 5000 hours on them. I have factory original 2 blade props. Also my sail drive transmissions start leaking water after only 150 hours from renewing the seals. When I get into this nasty chop on the nose, I hobby horse and virtually stop forward motion. This means motor sailing close hauled, fighting the waves, and sweeping through 120 degree tacks.

I was hoping that more horsepower would let me punch through the chop.

[Cheechako]

Originally Posted by CaptRDJR

Thanks for the feedback.

GSPEAKE,
To answer your question. I do most of my sailing on the Chesapeake Bay which is fairly shallow and can easily generate a 3+ foot chop in 15 to 20 kts of wind. My Volvo diesels are 28HP each and have about 5000 hours on them. I have factory original 2 blade props. Also my sail drive transmissions start leaking water after only 150 hours from renewing the seals. When I get into this nasty chop on the nose, I hobby horse and virtually stop forward motion. This means motor sailing close hauled, fighting the waves, and sweeping through 120 degree tacks.

I was hoping that more horsepower would let me punch through the chop.

If you do repower, consider a power train that you can upgrade props on , like Max Props etc. While they wont make you faster in flat water necessarily, they seem to thrust better when the going gets tough, or in reverse etc.

[DRS]

Originally Posted by CaptRDJR

I am looking at re-powering my 2002 Lagoon 380. Does anyone have experience upgrading the engines to 39/40HP. I do most of my sailing on the Chesapeake and wouldn't mind some extra power.

Thank you in advance for any help you can provide.

Last spring re-powered my 380 with Volvo D2-40s. You will need to modify the engine mounts a bit but they fit. Changed from 120 to 130 sail drives as well. It was actually a sail drive failure that made the change necessary

Derick

[CaptRDJR]

Derick - Thank you very much for your response. A couple of questions: 1) Did the 130 sail drive fit in the current through hull or did you need to modify the bottom? 2) What props are you using? 3) How did you performance improve? 4) What was the approximate cost?

[DRS]

It was a sail drive failure that caused the re-power. There are no parts available for the 120 series sail drives so I was going to have to change to a 130 series sail drive. The cost for the sail drive alone was 12K Canadian if you bought it as a package with the engine the entire package engine and sail drive was 15K.
I had almost 6000 hours on the engine so it was a no brainer from my perspective. The bad part of course is that there are TWO engines and sail drives on a cat so did them both. 30 boat units later...

The install was very simple as it all basically fit in the same place. The engine is a bit longer so as I said we had to modify the engine mounts to pull the engine forward and allow the sail drive to drop in the same hole.

I am running 2 blade Max Props. I was over pitched before and on the old 29 hp engines could not reach max RPM. Now I can but my cruising speed remains the same in the 2000 to 2400 RPM range. What I do notice now is that I can head into current or weather without the drop in speed i used to see. She seems to hold better in those conditions.

Hope that helps

PS if you know anyone that needs some 120 Series sail drive parts I have a complete unit (in parts) I'm trying to sell

[CaptRDJR]

Thank you again for the detailed response. It looks like I will be moving forward with the extra horse power.