Sealine F37 Best Cruise Speed?

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shanwick

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I have a 2005 Sealine F37 with Volvo D4-260 engines.

I am considering fitting fuel flow meters next year but in the meantime, is there anyone with an F37 that can help me out with the best cruise speed/rpm once on the plane?

I have tried to use the Volvo supplied data sheets but as these take no account of prop loading the figures are somewhat obscure.

Has anyone fitted Flowscan to this set-up or simply upgraded the Volvo gauges?

Many Thanks in advance.
 
I fitted Flowscan to Jeaneau 805, some boats ago, whilst it worked ok, it was a real pain to fit, you have to break into both sets of flow and return fuel lines, bleed the system etc.
I wouldn't both to do it again, no big benefit for me, wasn't worth the £800.
Someone will come along soon with typical figures for mpg, I bet it would be around 1 mile per gallon, average.
That said, it will all depend on many factors, weight, speed, sea state, etc
 
as per previous post - fuel consumption will depend on speed, load, sea state etc. spend the £800 on diesel and try not to dwell on the MPG - enjoy your boat.
 
shanwick said:
I have a 2005 Sealine F37 with Volvo D4-260 engines.

I am considering fitting fuel flow meters next year but in the meantime, is there anyone with an F37 that can help me out with the best cruise speed/rpm once on the plane?

I have tried to use the Volvo supplied data sheets but as these take no account of prop loading the figures are somewhat obscure.

Has anyone fitted Flowscan to this set-up or simply upgraded the Volvo gauges?

Many Thanks in advance.
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I'd love a pair of D4 260s in my boat. I have merc 220s

I reckon the hull gets to max efficiency when the tabs are right up and the nose is still far enough down. My engines are heavier than yours and run out of puff before the hull is at max efficiency.

I'd reckon the range 23 - 25 knots for your boat would be best. But as the engines are lighter you may be able to go a little slower and still be OK.
 
On a big boat like that I would say it is max revs less 15%.

Its clearly not overpowered and the faster you go the more efficient the props will be................

17 knots will be on the plane but the angle of your boat will be bow up, much of your prop thrust will be heading for the seabed and not providing forward momentum.

You max at 29 knots most days ?, back off 15% revs and you should be at 24 ish and level ish which means your propulsion is astern and not towards the seabed.

My boat is similar to yours ( P360 with twin 300 hp), a few years back we came back from CI trying to outrun a thunder storm, swalls of 50 knot winds, we came back @ 26 knots, when we filled up the mpg was the same as we used to get when running in @ 19 knots.

You should do better than 1 mpg @ 24 knots imho
 
shanwick said:
I have a 2005 Sealine F37 with Volvo D4-260 engines.

I am considering fitting fuel flow meters next year but in the meantime, is there anyone with an F37 that can help me out with the best cruise speed/rpm once on the plane?

I have tried to use the Volvo supplied data sheets but as these take no account of prop loading the figures are somewhat obscure.

Has anyone fitted Flowscan to this set-up or simply upgraded the Volvo gauges?

Many Thanks in advance.
Click to expand...

We have an F37 with KAMD300's and usually cruise at 3250-3300 rpm's which translates to around 22 - 23 knots (we usually have quite a bit of cruising gear + 50% water and fuel on board). We used to go a bit slower but found that the boat runs at a better trim and engines sound happier at this speed.

I personally haven't found a need for fuel flow meters as the difference that +/-1 knot makes in mpg is probably not that great.
 
Volvo usually say max rpm (not quoted max rpm but whatever max rpm your boat can achieve at the time) less 200rpm is max cruising speed but I dont think you can be specific about cruising rpm because it depends on the specific boat/engine combo. Every boat I've owned has had a sweet spot in the rpm range where the engines are purring along nicely but dont feel strained and the hull feels nicely balanced and is neither too much bow up or bow down. Its something you feel and hear rather than being a specific number in the rpm range
 
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