Question on possible top speed

[artcat]

Helping a buddy find a boat and we are looking at a 1991 Maxum 2100 SR with 4.3 mercruiser . This is his first boat and we know it will not be a lake rocket but what speed can we realistically expect. Not sure if it is 2 or 4 barrel,,i assume whatever was stock.I believe i saw a 21 pitch prop on it,,wish I would of checked out carb better. I just dont want him to get a pig that wont break 30 mph..

 

[Maclin]

It will break 40, might make 45 and some change maybe.

 

[QBhoy]

She’ll do well enough to get just over 40 gps and with the right prop, I’d think.

 

[bavedoggs]

You’ll break 40. I get 35-40 depending on prop in my 3.0 4cyl with the wife & kids.

 

[Scott Danforth]

I personally would want a 5.7 or larger in a 21' boat. however agree, you should break 40

 

[Alumarine]

You’ll break 40. I get 35-40 depending on prop in my 3.0 4cyl with the wife & kids.

You have a Maxum 2100 SR with a 3.0?

 

[Bondo]

Ayuh,.... I agree,.... 40 mph sounds 'bout right,....

 

[bavedoggs]

You have a Maxum 2100 SR with a 3.0?

No...I have a SeaRay but the specs on the Maxum tell me it will break 40. I also googled the 2100 w/ a 4.3..one guy shows 47mph @ WOT on 15.25” x 21P. Others have reported 42 MPH on a 4 blade prop, loaded to the gills.

 

[alldodge]

one guy shows 47mph @ WOT on 15.25” x 21P.

Might be stretching it a tad, or not using a gps

 

[artcat]

Thanks for all the replies,,,we are going to look at one tomorrow nite with a 220 hp V8..The Maxum was the nicest boat that we have looked at so far.. Is there a good site to look for a good used boat,,or is anyone on here looking to sell,,,if that is permitted to do. I have a 19ft aluminum with a 120 hp Johnny outboard that will run 45,,he wants to keep close to that if possible,,speed wise that is.

 

[QBhoy]

I can provide some up the to minute and slightly comparable info.
So we just put a 21” laser 2 prop on my friends newly acquired maxum 19sr bow rider. With the 4 barrel 4.3 Merc he achieved 46.9mph gps today. I wasn’t there but he was chuffed to bits with it. It was running light and probably almost about as quick as it will ever go.
Previously it ran at 42.4 mph gps with standard black max and just on the limiter a tad over 4800 rpm...so a fair improvement.
Cant say for certain, but it’s unlikely the larger, beamier and heavier 2100 with the same engine will achieve close to this. I’ll stand by my early 40’s original comment...with the right prop.
As for it keeping up with your boat...can’t stress enough the discrepancies between or amongst water pressure speedometers....if that’s what you go by.
My boat will indicate a guess of over 70mph if you judge the increments on its max 65mph printed faria speedo....but gps tells a different story all together. The reality is that most times it will only be doing early 60’s.
Youll find that way more than half the folk that claim a 50mph boat, simply don’t....and an even greater number don’t at the 60mph claim. 50mph is bloody quick on a boat....to get over this at true gps takes a fairly capable machine. Over 60 is a special thing again. The huge amounts of horsepower required in proportion to hull design and weight it rediculous.