Searay 420 Sedan Bridge - Cruising Speed

[Paul Ford]

HI all. I would like to see what other 2005 42 foot sedan bridge owners are getting for cruising and WOT speeds. I have dual Cummins C6 450HP Diamond's for engines.
Cruising 2400 rpm delivers about 18 Knots and Wide open at 2600 delivers about 21. I know this is a heavy boat but it still seems slow. Props are a little out of spec but not enough to hinder performance that much. Hull is also clean.

 

[440 Jim]

Paul,
Try the Sport yacht/yacht forum further down. There are some 420/440DB threads and owners there.

Thanks for coming over from THT.

 

[manfredr]

HI all. I would like to see what other 2005 42 foot sedan bridge owners are getting for cruising and WOT speeds. I have dual Cummins C6 450HP Diamond's for engines.
Cruising 2400 rpm delivers about 18 Knots and Wide open at 2600 delivers about 21. I know this is a heavy boat but it still seems slow. Props are a little out of spec but not enough to hinder performance that much. Hull is also clean.

Not too far off from mine! I get 19 knots at 2350 and about 22 at WOT. Depends a bit on fuel/water level and the tide of course!
I have a 2004 Sedan Bridge with the same engines.

 

[Steve S]

I have a 2000 400DB with the Cat 3116's. I get similar performance. At 2400 RPM I get 19.5-21 KTS based on wind and wave conditions. WOT will get me over 23 KTS.

These are stern heavy boats. I've found with about 1/2 tabs or more it will pickup some speed as the stern rises.

 

[saopm]

HI all. I would like to see what other 2005 42 foot sedan bridge owners are getting for cruising and WOT speeds. I have dual Cummins C6 450HP Diamond's for engines.
Cruising 2400 rpm delivers about 18 Knots and Wide open at 2600 delivers about 21. I know this is a heavy boat but it still seems slow. Props are a little out of spec but not enough to hinder performance that much. Hull is also clean.

Something isn’t right. I’m getting 21knots at 2250, and 23.5-24knots at 2350. I haven’t gone WOT since early spring, but believe it was around 27-28 knots.

 

[my3sons]

Something isn’t right. I’m getting 21knots at 2250, and 23.5-24knots at 2350. I haven’t gone WOT since early spring, but believe it was around 27-28 knots.

Agree. I run very close to these numbers when I’m loaded heavy. 2280 rpm gives 24+ smph full water, fuel and dinghy on the platform.
wot (2700+) is 31.5 smph
I wouldn’t think the 420’s should be much different.

 

[Alex F]

... I have dual Cummins C6 450HP Diamond's for engines.
Cruising 2400 rpm delivers about 18 Knots and Wide open at 2600 delivers about 21. I know this is a heavy boat but it still seems slow. Props are a little out of spec but not enough to hinder performance that much. Hull is also clean.

This is not normal, for this boat, even when you're fully overloaded (full of fuel, water, poop, gear, etc.). If you're only spinning 2600RPMS, you're slightly over propped, which means you should be running faster. You want to be in 2650-2700 (the closer to 2700 the better), which will cost you about 1-2kts. She should be running in a 25-27kts range, especially if you don't have heavy dinghy on the platform.

Something is missing here. Are you sure that your bottom and running gear are really clean? Are you using the tabs correctly? The boat is sensitive to all the variables, especially the tabs.