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What drive did this have or i should put on?

V

vroomZOOM

Regular Contributor
Hello

It is now the time when el cheapo (me) starts looking for another boat to wrench on. I found a good looking boat, 2003 larson 310 cabrio on a trailer, but both drives are missing. They where mercruiser drives, but alpha or bravo? I, II or III? I heard there is a way to find out by looking at the engine, the water pump is on the engine? If I where to buy the boat, where can I find some decent used drives, and which ones would I want (an alpha 3 of course lol) the bravo 1, 2, 3, or alpha? What are the pros and cons of these drives and what ballpark price am I looking at to get them. I attached a picture of the front of one of the engines, maybe you can tell by that? Imo the alpha would not hold up on a boat that big, so B1, B2 or B3?
03 cabrio 310 engine.jpg
 
Not an alpha the sea water pump gives it away as a bravo set up. With duals you could use bravo ones and avoid any of the corrosion issues associated with bravo iiis
 
post a pic of the transom. Usually the 5.7 is the biggest motor used with Alpha GEN II . You have a engine mounted raw water pump so that deletes the Alpha so then you had Bravo`s
B1 single prop, B2 heavy duty swings a large prop, B3 dual props
 
What drives would be the best performance wise? price wise? availability wise? what is the difference between the 1 and 2? sorry for all the questions but I am pretty new to bravo's. edit: I found it had BIII's on it.
 
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Yup has sure signs of inundation whether it sank at the dock or filled with rainwater. Personally, I would have it surveyed before even considering dragging it home. There's always a reason why stuff is cheap. And it ends up that it isn't in the long run.
If you want a big boat, your best bet is long term financing or chartering. Chartering is great. You get the use of the boat, and when your trip is over you walk away with your boating jones satisfied. Most boats just sit around all the time. Why pay and pay for something if you rarely use it?
 
vroomZOOM said:
What drives would be the best performance wise? price wise? availability wise? what is the difference between the 1 and 2? sorry for all the questions but I am pretty new to bravo's. edit: I found it had BIII's on it.
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The drives don't come into play as much as hull shape, payload, and weather. You have X horsepower turning X propellers. You're pretty much limited by that.
With twin engines you already have improved low speed handling, so the BIII is simply gilding the lily so to speak but those drives do offer better straight line tracking, low speed handling (docking). A dual prop drive is not going to have "prop steer" as the second prop negates this phenomenon. Both drives are "standard" rotation.
With the Bravo II the drives must be standard (usually on the starboard side) and reverse rotation to counteract the effect of prop steer.
While I have not handled a twin engine boat with Bravo Three drives, I can imagine it's quite a bit nicer than a boat with single prop drives.
 
Docksidemarineservices said:
By the looks of the bilge with all the mud, Make sure the engines run.
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uhh... yeah... of course I will! Im having an inspector go out there and look at it for me. And yes, I am taking the price of drives into account... its got to be a deal or else I am NEVER buying it. I had to learn the bad engine lesson the hard way! There was another one that sold for $975 but with volvos and outdrives - 1998. ugh... I had a heart attack when I knew I missed that one... the drives are worth more than that!
 
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If there was any kind of inundation you will have to replace all the wiring. If a wire gets water inside it's boo hao. Battery cables esp. I would be very very particular about this as many modern boats run the wiring between the hull and hull liner making it just about impossible to access, let alone replace, a circuit.
 
o2batsea said:
If there was any kind of inundation you will have to replace all the wiring. If a wire gets water inside it's boo hao. Battery cables esp. I would be very very particular about this as many modern boats run the wiring between the hull and hull liner making it just about impossible to access, let alone replace, a circuit.
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Thank you, good to know!
 
As of 2019 there is no more Larson Boats. The brand was scooped up by Polaris and has been sidelined. If you try to contact Larson through Larsonboats.com you get a 404. That means that any information that you hope to get for this boat will have to come from existing resources; on line brochures and manuals, forums, etc.
Answers to questions like what drive ratio would have been simpler if there was still a Larson Boats corporate existence as you could call or write and probably get an answer from one of the old-timers.
I have the same issue with my "antique". Not many Allmands were made and there is almost no resources out there for information.

If you wanna wing it, you'll be pretty safe choosing a 2:1 ratio and then do final trimming with prop selection. This is kind of a black art, and can take two or three tries to get it right. You'll definitely want to enlist the help of a good prop shop. They will sea trial the boat with several combinations and fit the best ones. This is a fairly big undertaking but well worth the effort and expense. Good props can make a good boat great. Incorrect props can make a good boat a dog.
 
Ok, 2:1 it is, might be right for that size of boat with twin 350s. I just thought it was like the alpha, where there is a certain drive ratio meant for a certain engine (e.g 1.98 for a 3.0, etc).
 
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