Boat Speed

[DOCKMASTER]

I have been negotiating the purchase of a Luhrs Tournament SF. During due diligence I could not miss the vast differences in claimed cruise and top end speeds of boats of the same model, year and power. I can understand propeller pitches, types of bottom paint, fuel and tackle, and some subjectivity on what constitutes cruise RPM can make a 1 or 2 knot difference, but not on the top end speed. I am seeing from 5 to 7 knot differences advertised on identical boats which simply does not seem possible if all other things are equal. My sea trial produced a 5 knot difference from what was advertised which I felt was a gross misrepresentation on the part of the listing broker. I was quite upset (to say the least) having flown 650 miles and spent in excess of $1,500.00 to conduct a survey and sea trial. My local broker tells me he always errors on the low side and that is generally an accepted industry practice. I am getting these differences on Yacht World which I understood was a Yacht Brokers venue. If so is there no integrity among these individuals. Since this is a precautionary post, does anyone have a comment or insight they might like to share on this subject other than "Let the Buyer Beware".

[CaptnJack]

Three things boat owners lie about how much they paid and how fast/fuel consumption this boat will get..............
Rule of thumb trust knowbody!!!!

[witeagle]

There are a lot of factors in play with cruise and top speed.

Mechanical (engines/prop)
Boat bottom condition (paint and any growth)
Sea Conditions (tide and wave)
Wind/Weather Conditions

When I had my 1st sea trial the boat ran really slow and could not get up to a decent speed. However, there was a ton of growth on the bottom from the boat sitting at the dealer's marina and not run to keep growth down.

After a haul and preasure wash, the boat ran much better with the correct cruise speed and top speed for the engine package in the boat.

[DOCKMASTER]

In answer to witeagle, All of this was taken into consideration. The boat was hauled and the bottom cleaned. The props look fine not dinged or bent, trim tabs were operational, boat had 1/2 fuel (200 Gal) an empty holding tank not sure how much water but could not have been much. I think CaptnJack's response was accurate, "3 Things Boat Owners Lie About" I guess the Honor among Yacht Brokers is well do I need to say it?

[irishrogue]

i guess looking at identical boats with similar power on yachtworld showing a range of different cruising and WOT speeds should have tipped you off....realistically, many of those listings are inaccurate because of lazy brokers - there are a good many cross listings on that site as well. i would confirm all info with a broker before travelling to see a boat.

[CrazyIslandMoFo]

Just about every boat is set up diffrent, gear ratio,safty gear, extra parts? Was there water in the live well, how about the fresh water tank? Tide, wind,and waves will have dramatic effect. We dove on my luhrs last week, in only a few months with steady use a few times a week, we scraped off 5-10 gal. of barnacles and growth. I have regained 5-7 knots at cruse, and again handles like a sports star... I thought I needed to replace my cullas berings, turns out it was a giant growth of barnacles on one side of the prop shaft. My luhrs has a tower and out riggers. This adds to wind drag and weight. I carry a lot fo survival gear , raft, immerison suits, eperbs, 10 life jackets. off shore flair kits, mulitple fire extinguishers... Reality is, every pound on a boat makes a diffrence. You should be sure of what your hauling around before you make your comparisons.

[irishrogue]

i cant speak to precislely what effect a dirty bottom has on cruise/wot of the 32 open (we never get more than slime in NJ with VC offshore....)

BUT the 320 open with 350 cat diesels is not greatly affected at cruise speeds by # of persons on board or full fuel. our boat runs maybe 1-2kt difference at cruise when we have a 1/2 load of fuel and 3 people vs. full load fuel + fishing gear + 150lbs ice + 5 guys. so roughly 1700lbs = 1-2 kts at cruise....so a 10% weight increase equals less than a 10% speed drop...roughly.....i have no idea if this "equation" is linear....

with a light load of fuel, no water and 2 people our WOT does go up by maybe 2+ kts.

[irishrogue]

a big question here is props - 3 blade, 4 blade? properly pitched? bronze, nibral? older 3 blade bronze props with the pitch out could easily account for 3 kts at cruise over newer 4 blade nibrals properly pitched...