jclays
Senior Member
Ouch!
Trim tabs on Trawlers
- Thread starter jclays
- Start date
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Ouch!
Nomad Willy
Guru
Cruisers can use trim tabs.
Using tabs for list control is stupid or just lazy. Why not put the weight where it belongs?
Trawlers don’t go fast enough to be able to use tabs. The drag when deployed is so great that it’s very unlikely one could get enough lift to trim the boat so there’s less drag that w/o tabs. The excessive weight of the trawler has a lot to do w this.
Money thrown down the boating money hole .. IMO.
Using tabs for list control is stupid or just lazy. Why not put the weight where it belongs?
Trawlers don’t go fast enough to be able to use tabs. The drag when deployed is so great that it’s very unlikely one could get enough lift to trim the boat so there’s less drag that w/o tabs. The excessive weight of the trawler has a lot to do w this.
Money thrown down the boating money hole .. IMO.
- Joined
- Mar 17, 2012
- Messages
- 4,279
- Location
- Australia
- Vessel Name
- Insequent
- Vessel Make
- Ocean Alexander 50 Mk I
I was varnishing some teak rails earlier in the week when this guy and his wife, who were riding their bikes along the boardwalk, shouted out a question: "Is that a cruiser?" So, rather than get into a debate or explanation about recreational trawlers I just said "sure". 
When non-boating people ask what kind of boat I have I usually say "motor cruiser". The use of "trawler" down here would typically imply the fishing type.
My boat had trim tabs when I bought it. Bennett, and fairly large ones at 48" x 24" each side. They were needed at anything over 10kn, and worked very well to stop the bow from pointing to the stars and get the stern out of a hole. At WOT I could get 17kn, but burning around 130 litres per hour. On the other hand running at 8-9kn would use 20-30 litres per hour. At these slower speeds the trim tabs were not needed to control bow angle, and as I was installing Naiad's I did not need lateral trim from trim tabs either.
So when I did my re-power and refit I installed smaller engines (2 x 200HP replaced 2 x 270HP) and removed the trim tabs. After 7 years , what would I do different if I had my time over? One of two things, either:
- the common rail version of the same engine (JD 6068) which could provide up to 400HP each. Provided it did not force larger shaft size and new props. In this case the trim tabs would have been needed still.
- or find a pair of 150HP engines. They would still be more than enough for 8-9kn. No trim tabs in that case. But cost and weight savings may not be all that significant. It would come down to preference for an engine manufacturer and any deals available.
Neither option would change the way I normally run. I would seldom run at twice my normal speed for a multiple of 6 or 7 times the fuel burn. Indeed, after 15,000nm of cruising I can't recall any time that speed in the high teens would have been used for anything other than demonstrating what the boat could do.
On the other hand I do find myself thinking, usually during a 100nm leg of a Reef cruise, that 12kn cruise (at better than 1 nmpg) would be really nice. But I'll need a longer & skinnier boat for that! Those dawn-to-dusk runs are not done often and generally not that tiring, except when part of the day has wind against tide conditions and the wind gets up to 20kn or above.
So basically no regrets on engine choice and trim tab removal. I would try harder to find a light & skinny 60'er if doing it again. At the time my heart was saying build Tad's Passagemaker Lite. The 56', but extended a little. However; back in those post-GFC times (1A$=1.09US$, those were the days my friend!) it simply did not make financial sense to build new given the range, quality and quantity of used boats in the US.
When non-boating people ask what kind of boat I have I usually say "motor cruiser". The use of "trawler" down here would typically imply the fishing type.
My boat had trim tabs when I bought it. Bennett, and fairly large ones at 48" x 24" each side. They were needed at anything over 10kn, and worked very well to stop the bow from pointing to the stars and get the stern out of a hole. At WOT I could get 17kn, but burning around 130 litres per hour. On the other hand running at 8-9kn would use 20-30 litres per hour. At these slower speeds the trim tabs were not needed to control bow angle, and as I was installing Naiad's I did not need lateral trim from trim tabs either.
So when I did my re-power and refit I installed smaller engines (2 x 200HP replaced 2 x 270HP) and removed the trim tabs. After 7 years , what would I do different if I had my time over? One of two things, either:
- the common rail version of the same engine (JD 6068) which could provide up to 400HP each. Provided it did not force larger shaft size and new props. In this case the trim tabs would have been needed still.
- or find a pair of 150HP engines. They would still be more than enough for 8-9kn. No trim tabs in that case. But cost and weight savings may not be all that significant. It would come down to preference for an engine manufacturer and any deals available.
Neither option would change the way I normally run. I would seldom run at twice my normal speed for a multiple of 6 or 7 times the fuel burn. Indeed, after 15,000nm of cruising I can't recall any time that speed in the high teens would have been used for anything other than demonstrating what the boat could do.
On the other hand I do find myself thinking, usually during a 100nm leg of a Reef cruise, that 12kn cruise (at better than 1 nmpg) would be really nice. But I'll need a longer & skinnier boat for that! Those dawn-to-dusk runs are not done often and generally not that tiring, except when part of the day has wind against tide conditions and the wind gets up to 20kn or above.
So basically no regrets on engine choice and trim tab removal. I would try harder to find a light & skinny 60'er if doing it again. At the time my heart was saying build Tad's Passagemaker Lite. The 56', but extended a little. However; back in those post-GFC times (1A$=1.09US$, those were the days my friend!) it simply did not make financial sense to build new given the range, quality and quantity of used boats in the US.
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